Remove nullOk in MediaQuery.of (#68736)

Adds MediaQuery.maybeOf to replace calling MediaQuery.of(context, nullOk: true), and removes the nullOk parameter. Also changes MediaQuery.of to return a non-nullable value, and removes many instances of the ! operator, reducing the possible places where a null dereference could occur.

examples/layers/widgets/media_query.dart

@@ -71,7 +71,7 @@ class AdaptiveContainer extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    if (MediaQuery.of(context)!.size.width < _kGridViewBreakpoint) {
+    if (MediaQuery.of(context).size.width < _kGridViewBreakpoint) {
       return ListView(
         itemExtent: _kListItemExtent,
         children: names.map<Widget>((String name) => AdaptedListItem(name: name)).toList(),

packages/flutter/lib/src/cupertino/action_sheet.dart

@@ -274,12 +274,12 @@ class CupertinoActionSheet extends StatelessWidget {
       if (cancelButton != null) _buildCancelButton(),
     ];
 
-    final Orientation orientation = MediaQuery.of(context)!.orientation;
+    final Orientation orientation = MediaQuery.of(context).orientation;
     final double actionSheetWidth;
     if (orientation == Orientation.portrait) {
-      actionSheetWidth = MediaQuery.of(context)!.size.width - (_kEdgeHorizontalPadding * 2);
+      actionSheetWidth = MediaQuery.of(context).size.width - (_kEdgeHorizontalPadding * 2);
     } else {
-      actionSheetWidth = MediaQuery.of(context)!.size.height - (_kEdgeHorizontalPadding * 2);
+      actionSheetWidth = MediaQuery.of(context).size.height - (_kEdgeHorizontalPadding * 2);
     }
 
     return SafeArea(
@@ -449,7 +449,7 @@ class _CupertinoAlertRenderWidget extends RenderObjectWidget {
   RenderObject createRenderObject(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
     return _RenderCupertinoAlert(
-      dividerThickness: _kDividerThickness / MediaQuery.of(context)!.devicePixelRatio,
+      dividerThickness: _kDividerThickness / MediaQuery.of(context).devicePixelRatio,
       dividerColor: CupertinoDynamicColor.resolve(_kButtonDividerColor, context)!,
     );
   }
@@ -944,7 +944,7 @@ class _CupertinoAlertActionSection extends StatefulWidget {
 class _CupertinoAlertActionSectionState extends State<_CupertinoAlertActionSection> {
   @override
   Widget build(BuildContext context) {
-    final double devicePixelRatio = MediaQuery.of(context)!.devicePixelRatio;
+    final double devicePixelRatio = MediaQuery.of(context).devicePixelRatio;
 
     final List<Widget> interactiveButtons = <Widget>[];
     for (int i = 0; i < widget.children.length; i += 1) {

packages/flutter/lib/src/cupertino/bottom_tab_bar.dart

@@ -143,7 +143,7 @@ class CupertinoTabBar extends StatelessWidget implements PreferredSizeWidget {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final double bottomPadding = MediaQuery.of(context)!.padding.bottom;
+    final double bottomPadding = MediaQuery.of(context).padding.bottom;
 
     final Color? backgroundColor = CupertinoDynamicColor.resolve(
       this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor,

packages/flutter/lib/src/cupertino/colors.dart

@@ -944,13 +944,18 @@ class CupertinoDynamicColor extends Color with Diagnosticable {
   /// level), unless [nullOk] is set to false, in which case an exception will be
   /// thrown.
   CupertinoDynamicColor resolveFrom(BuildContext context, { bool nullOk = true }) {
-    final Brightness brightness = _isPlatformBrightnessDependent
+    Brightness brightness = Brightness.light;
-      ? CupertinoTheme.brightnessOf(context, nullOk: nullOk) ?? Brightness.light
+    if (_isPlatformBrightnessDependent) {
-      : Brightness.light;
+      brightness = nullOk
-
+          ? CupertinoTheme.maybeBrightnessOf(context) ?? Brightness.light
-    final bool isHighContrastEnabled = _isHighContrastDependent
+          : CupertinoTheme.brightnessOf(context);
-      && (MediaQuery.of(context, nullOk: nullOk)?.highContrast ?? false);
+    }
-
+    bool isHighContrastEnabled = false;
+    if (_isHighContrastDependent) {
+      isHighContrastEnabled = nullOk
+          ? MediaQuery.maybeOf(context)?.highContrast ?? false
+          : MediaQuery.of(context).highContrast;
+    }
 
     final CupertinoUserInterfaceLevelData level = _isInterfaceElevationDependent
       ? CupertinoUserInterfaceLevel.of(context, nullOk: nullOk) ?? CupertinoUserInterfaceLevelData.base

packages/flutter/lib/src/cupertino/context_menu.dart

@@ -253,7 +253,7 @@ class _CupertinoContextMenuState extends State<CupertinoContextMenu> with Ticker
   // it.
   _ContextMenuLocation get _contextMenuLocation {
     final Rect childRect = _getRect(_childGlobalKey);
-    final double screenWidth = MediaQuery.of(context)!.size.width;
+    final double screenWidth = MediaQuery.of(context).size.width;
 
     final double center = screenWidth / 2;
     final bool centerDividesChild = childRect.left < center
@@ -1081,7 +1081,7 @@ class _ContextMenuRouteStaticState extends State<_ContextMenuRouteStatic> with T
   Widget _buildChildAnimation(BuildContext context, Widget? child) {
     _lastScale = _getScale(
       widget.orientation,
-      MediaQuery.of(context)!.size.height,
+      MediaQuery.of(context).size.height,
       _moveAnimation.value.dy,
     );
     return Transform.scale(

packages/flutter/lib/src/cupertino/date_picker.dart

@@ -1032,7 +1032,7 @@ class _CupertinoDatePickerDateTimeState extends State<CupertinoDatePicker> {
     }
 
     return MediaQuery(
-      data: MediaQuery.of(context)!.copyWith(textScaleFactor: 1.0),
+      data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
       child: DefaultTextStyle.merge(
         style: _kDefaultPickerTextStyle,
         child: CustomMultiChildLayout(
@@ -1403,7 +1403,7 @@ class _CupertinoDatePickerDateState extends State<CupertinoDatePicker> {
     }
 
     return MediaQuery(
-      data: MediaQuery.of(context)!.copyWith(textScaleFactor: 1.0),
+      data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
       child: DefaultTextStyle.merge(
         style: _kDefaultPickerTextStyle,
         child: CustomMultiChildLayout(
@@ -2077,7 +2077,7 @@ class _CupertinoTimerPickerState extends State<CupertinoTimerPicker> {
         return MediaQuery(
           // The native iOS picker's text scaling is fixed, so we will also fix it
           // as well in our picker.
-          data: MediaQuery.of(context)!.copyWith(textScaleFactor: 1.0),
+          data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
           child: CupertinoTheme(
             data: themeData.copyWith(
               textTheme: themeData.textTheme.copyWith(

packages/flutter/lib/src/cupertino/dialog.dart

@@ -95,7 +95,7 @@ const double _kMaxRegularTextScaleFactor = 1.4;
 // Accessibility mode on iOS is determined by the text scale factor that the
 // user has selected.
 bool _isInAccessibilityMode(BuildContext context) {
-  final MediaQueryData? data = MediaQuery.of(context, nullOk: true);
+  final MediaQueryData? data = MediaQuery.maybeOf(context);
   return data != null && data.textScaleFactor > _kMaxRegularTextScaleFactor;
 }
 
@@ -228,18 +228,18 @@ class CupertinoAlertDialog extends StatelessWidget {
   Widget build(BuildContext context) {
     final CupertinoLocalizations localizations = CupertinoLocalizations.of(context);
     final bool isInAccessibilityMode = _isInAccessibilityMode(context);
-    final double textScaleFactor = MediaQuery.of(context)!.textScaleFactor;
+    final double textScaleFactor = MediaQuery.of(context).textScaleFactor;
     return CupertinoUserInterfaceLevel(
       data: CupertinoUserInterfaceLevelData.elevated,
       child: MediaQuery(
-        data: MediaQuery.of(context)!.copyWith(
+        data: MediaQuery.of(context).copyWith(
           // iOS does not shrink dialog content below a 1.0 scale factor
           textScaleFactor: math.max(textScaleFactor, 1.0),
         ),
         child: LayoutBuilder(
           builder: (BuildContext context, BoxConstraints constraints) {
             return AnimatedPadding(
-              padding: MediaQuery.of(context)!.viewInsets +
+              padding: MediaQuery.of(context).viewInsets +
                   const EdgeInsets.symmetric(horizontal: 40.0, vertical: 24.0),
               duration: insetAnimationDuration,
               curve: insetAnimationCurve,
@@ -388,7 +388,7 @@ class _CupertinoDialogRenderWidget extends RenderObjectWidget {
   @override
   RenderObject createRenderObject(BuildContext context) {
     return _RenderCupertinoDialog(
-      dividerThickness: _kDividerThickness / MediaQuery.of(context)!.devicePixelRatio,
+      dividerThickness: _kDividerThickness / MediaQuery.of(context).devicePixelRatio,
       isInAccessibilityMode: _isInAccessibilityMode(context),
       dividerColor: CupertinoDynamicColor.resolve(CupertinoColors.separator, context)!,
     );
@@ -877,7 +877,7 @@ class _CupertinoAlertContentSection extends StatelessWidget {
       );
     }
 
-    final double textScaleFactor = MediaQuery.of(context)!.textScaleFactor;
+    final double textScaleFactor = MediaQuery.of(context).textScaleFactor;
     final List<Widget> titleContentGroup = <Widget>[
       if (title != null)
         Padding(
@@ -954,7 +954,7 @@ class _CupertinoAlertActionSection extends StatefulWidget {
 class _CupertinoAlertActionSectionState extends State<_CupertinoAlertActionSection> {
   @override
   Widget build(BuildContext context) {
-    final double devicePixelRatio = MediaQuery.of(context)!.devicePixelRatio;
+    final double devicePixelRatio = MediaQuery.of(context).devicePixelRatio;
 
     final List<Widget> interactiveButtons = <Widget>[];
     for (int i = 0; i < widget.children.length; i += 1) {

packages/flutter/lib/src/cupertino/nav_bar.dart

@@ -713,7 +713,7 @@ class _CupertinoSliverNavigationBarState extends State<CupertinoSliverNavigation
       actionsForegroundColor,
       context,
       MediaQuery(
-        data: MediaQuery.of(context)!.copyWith(textScaleFactor: 1),
+        data: MediaQuery.of(context).copyWith(textScaleFactor: 1),
         child: SliverPersistentHeader(
           pinned: true, // iOS navigation bars are always pinned.
           delegate: _LargeTitleNavigationBarSliverDelegate(
@@ -727,7 +727,7 @@ class _CupertinoSliverNavigationBarState extends State<CupertinoSliverNavigation
             actionsForegroundColor: actionsForegroundColor,
             transitionBetweenRoutes: widget.transitionBetweenRoutes,
             heroTag: widget.heroTag,
-            persistentHeight: _kNavBarPersistentHeight + MediaQuery.of(context)!.padding.top,
+            persistentHeight: _kNavBarPersistentHeight + MediaQuery.of(context).padding.top,
             alwaysShowMiddle: widget.middle != null,
           ),
         ),
@@ -960,7 +960,7 @@ class _PersistentNavigationBar extends StatelessWidget {
     }
 
     return SizedBox(
-      height: _kNavBarPersistentHeight + MediaQuery.of(context)!.padding.top,
+      height: _kNavBarPersistentHeight + MediaQuery.of(context).padding.top,
       child: SafeArea(
         bottom: false,
         child: paddedToolbar,
@@ -1631,7 +1631,7 @@ class _NavigationBarTransition extends StatelessWidget {
     // can actually be outside the linearly lerp'ed Rect in the middle of
     // the animation, such as the topLargeTitle.
     return SizedBox(
-      height: math.max(heightTween.begin!, heightTween.end!) + MediaQuery.of(context)!.padding.top,
+      height: math.max(heightTween.begin!, heightTween.end!) + MediaQuery.of(context).padding.top,
       width: double.infinity,
       child: Stack(
         children: children,

packages/flutter/lib/src/cupertino/page_scaffold.dart

@@ -93,7 +93,7 @@ class _CupertinoPageScaffoldState extends State<CupertinoPageScaffold> {
   Widget build(BuildContext context) {
     Widget paddedContent = widget.child;
 
-    final MediaQueryData existingMediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData existingMediaQuery = MediaQuery.of(context);
     if (widget.navigationBar != null) {
       // TODO(xster): Use real size after partial layout instead of preferred size.
       // https://github.com/flutter/flutter/issues/12912

packages/flutter/lib/src/cupertino/route.dart

@@ -691,8 +691,8 @@ class _CupertinoBackGestureDetectorState<T> extends State<_CupertinoBackGestureD
     // For devices with notches, the drag area needs to be larger on the side
     // that has the notch.
     double dragAreaWidth = Directionality.of(context) == TextDirection.ltr ?
-                           MediaQuery.of(context)!.padding.left :
+                           MediaQuery.of(context).padding.left :
-                           MediaQuery.of(context)!.padding.right;
+                           MediaQuery.of(context).padding.right;
     dragAreaWidth = max(dragAreaWidth, _kBackGestureWidth);
     return Stack(
       fit: StackFit.passthrough,

packages/flutter/lib/src/cupertino/scrollbar.dart

@@ -285,7 +285,7 @@ class _CupertinoScrollbarState extends State<CupertinoScrollbar> with TickerProv
       _painter!
         ..textDirection = Directionality.of(context)!
         ..color = CupertinoDynamicColor.resolve(_kScrollbarColor, context)!
-        ..padding = MediaQuery.of(context)!.padding;
+        ..padding = MediaQuery.of(context).padding;
     }
     _triggerScrollbar();
   }
@@ -315,7 +315,7 @@ class _CupertinoScrollbarState extends State<CupertinoScrollbar> with TickerProv
       mainAxisMargin: _kScrollbarMainAxisMargin,
       crossAxisMargin: _kScrollbarCrossAxisMargin,
       radius: _radius,
-      padding: MediaQuery.of(context)!.padding,
+      padding: MediaQuery.of(context).padding,
       minLength: _kScrollbarMinLength,
       minOverscrollLength: _kScrollbarMinOverscrollLength,
     );

packages/flutter/lib/src/cupertino/tab_scaffold.dart

@@ -388,8 +388,8 @@ class _CupertinoTabScaffoldState extends State<CupertinoTabScaffold> with Restor
 
   @override
   Widget build(BuildContext context) {
-    final MediaQueryData existingMediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData existingMediaQuery = MediaQuery.of(context);
-    MediaQueryData newMediaQuery = MediaQuery.of(context)!;
+    MediaQueryData newMediaQuery = MediaQuery.of(context);
 
     Widget content = _TabSwitchingView(
       currentTabIndex: _controller.index,

packages/flutter/lib/src/cupertino/text_field.dart

@@ -881,7 +881,7 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with Restoratio
     final List<TextInputFormatter> formatters = widget.inputFormatters ?? <TextInputFormatter>[];
     final TextSelectionControls textSelectionControls = widget.selectionControls ?? cupertinoTextSelectionControls;
     final bool enabled = widget.enabled ?? true;
-    final Offset cursorOffset = Offset(_iOSHorizontalCursorOffsetPixels / MediaQuery.of(context)!.devicePixelRatio, 0);
+    final Offset cursorOffset = Offset(_iOSHorizontalCursorOffsetPixels / MediaQuery.of(context).devicePixelRatio, 0);
     if (widget.maxLength != null && widget.maxLengthEnforced) {
       formatters.add(LengthLimitingTextInputFormatter(widget.maxLength));
     }
@@ -901,7 +901,7 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with Restoratio
 
     final TextStyle placeholderStyle = textStyle.merge(resolvedPlaceholderStyle);
 
-    final Brightness keyboardAppearance = widget.keyboardAppearance ?? CupertinoTheme.brightnessOf(context)!;
+    final Brightness keyboardAppearance = widget.keyboardAppearance ?? CupertinoTheme.brightnessOf(context);
     final Color cursorColor = CupertinoDynamicColor.resolve(widget.cursorColor, context) ?? themeData.primaryColor;
     final Color? disabledColor = CupertinoDynamicColor.resolve(_kDisabledBackground, context);
 

packages/flutter/lib/src/cupertino/text_selection.dart

@@ -157,7 +157,7 @@ class _CupertinoTextSelectionToolbarWrapperState extends State<_CupertinoTextSel
       ? EdgeInsets.only(bottom: _kToolbarArrowSize.height)
       : EdgeInsets.only(top: _kToolbarArrowSize.height);
     final Widget onePhysicalPixelVerticalDivider =
-        SizedBox(width: 1.0 / MediaQuery.of(context)!.devicePixelRatio);
+        SizedBox(width: 1.0 / MediaQuery.of(context).devicePixelRatio);
 
     void addToolbarButton(
       String text,
@@ -463,7 +463,7 @@ class _CupertinoTextSelectionControls extends TextSelectionControls {
     ClipboardStatusNotifier clipboardStatus,
   ) {
     assert(debugCheckHasMediaQuery(context));
-    final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
 
     // The toolbar should appear below the TextField when there is not enough
     // space above the TextField to show it, assuming there's always enough space
@@ -664,7 +664,7 @@ class _CupertinoTextSelectionToolbarContentState extends State<_CupertinoTextSel
             pressedOpacity: 0.7,
             child: const Text('◀', style: _kToolbarButtonFontStyle),
           ),
-          dividerWidth: 1.0 / MediaQuery.of(context)!.devicePixelRatio,
+          dividerWidth: 1.0 / MediaQuery.of(context).devicePixelRatio,
           nextButton: CupertinoButton(
             borderRadius: null,
             color: _kToolbarBackgroundColor,

packages/flutter/lib/src/cupertino/theme.dart

@@ -78,15 +78,37 @@ class CupertinoTheme extends StatelessWidget {
   /// is null, it will fall back to [MediaQueryData.platformBrightness].
   ///
   /// Throws an exception if no valid [CupertinoTheme] or [MediaQuery] widgets
-  /// exist in the ancestry tree, unless [nullOk] is set to true.
+  /// exist in the ancestry tree.
+  ///
+  /// See also:
+  ///
+  /// * [maybeBrightnessOf], which returns null if no valid [CupertinoTheme] or
+  ///   [MediaQuery] exists, instead of throwing.
+  /// * [CupertinoThemeData.brightness], the property takes precedence over
+  ///   [MediaQueryData.platformBrightness] for descendant Cupertino widgets.
+  static Brightness brightnessOf(BuildContext context) {
+    final _InheritedCupertinoTheme? inheritedTheme = context.dependOnInheritedWidgetOfExactType<_InheritedCupertinoTheme>();
+    return inheritedTheme?.theme.data.brightness ?? MediaQuery.of(context).platformBrightness;
+  }
+
+  /// Retrieves the [Brightness] to use for descendant Cupertino widgets, based
+  /// on the value of [CupertinoThemeData.brightness] in the given [context].
+  ///
+  /// If no [CupertinoTheme] can be found in the given [context], it will fall
+  /// back to [MediaQueryData.platformBrightness].
+  ///
+  /// Returns null if no valid [CupertinoTheme] or [MediaQuery] widgets exist in
+  /// the ancestry tree.
   ///
   /// See also:
   ///
   /// * [CupertinoThemeData.brightness], the property takes precedence over
   ///   [MediaQueryData.platformBrightness] for descendant Cupertino widgets.
-  static Brightness? brightnessOf(BuildContext context, { bool nullOk = false }) {
+  /// * [brightnessOf], which throws if no valid [CupertinoTheme] or
+  ///   [MediaQuery] exists, instead of returning null.
+  static Brightness? maybeBrightnessOf(BuildContext context) {
     final _InheritedCupertinoTheme? inheritedTheme = context.dependOnInheritedWidgetOfExactType<_InheritedCupertinoTheme>();
-    return inheritedTheme?.theme.data.brightness ?? MediaQuery.of(context, nullOk: nullOk)?.platformBrightness;
+    return inheritedTheme?.theme.data.brightness ?? MediaQuery.maybeOf(context)?.platformBrightness;
   }
 
   /// The widget below this widget in the tree.

packages/flutter/lib/src/material/about.dart

@@ -1018,7 +1018,7 @@ const double _wideGutterSize = 24.0;
 const double _narrowGutterSize = 12.0;
 
 double _getGutterSize(BuildContext context) =>
-    MediaQuery.of(context)!.size.width >= _materialGutterThreshold ? _wideGutterSize : _narrowGutterSize;
+    MediaQuery.of(context).size.width >= _materialGutterThreshold ? _wideGutterSize : _narrowGutterSize;
 
 /// Signature for the builder callback used by [_MasterDetailFlow].
 typedef _MasterViewBuilder = Widget Function(BuildContext context, bool isLateralUI);
@@ -1627,7 +1627,7 @@ class _DetailView extends StatelessWidget {
     if (_arguments == null) {
       return Container();
     }
-    final double screenHeight = MediaQuery.of(context)!.size.height;
+    final double screenHeight = MediaQuery.of(context).size.height;
     final double minHeight = (screenHeight - kToolbarHeight) / screenHeight;
 
     return DraggableScrollableSheet(

packages/flutter/lib/src/material/app_bar.dart

@@ -593,7 +593,7 @@ class _AppBarState extends State<AppBar> {
       // sizes. To opt out, wrap the [title] widget in a [MediaQuery] widget
       // with [MediaQueryData.textScaleFactor] set to
       // `MediaQuery.textScaleFactorOf(context)`.
-      final MediaQueryData mediaQueryData = MediaQuery.of(context)!;
+      final MediaQueryData mediaQueryData = MediaQuery.of(context);
       title = MediaQuery(
         data: mediaQueryData.copyWith(
           textScaleFactor: math.min(
@@ -1447,7 +1447,7 @@ class _SliverAppBarState extends State<SliverAppBar> with TickerProviderStateMix
   Widget build(BuildContext context) {
     assert(!widget.primary || debugCheckHasMediaQuery(context));
     final double bottomHeight = widget.bottom?.preferredSize.height ?? 0.0;
-    final double topPadding = widget.primary ? MediaQuery.of(context)!.padding.top : 0.0;
+    final double topPadding = widget.primary ? MediaQuery.of(context).padding.top : 0.0;
     final double collapsedHeight = (widget.pinned && widget.floating && widget.bottom != null)
       ? (widget.collapsedHeight ?? 0.0) + bottomHeight + topPadding
       : (widget.collapsedHeight ?? widget.toolbarHeight) + bottomHeight + topPadding;

packages/flutter/lib/src/material/bottom_navigation_bar.dart

@@ -657,7 +657,7 @@ class _Label extends StatelessWidget {
     if (item.label != null) {
       // Do not grow text in bottom navigation bar when we can show a tooltip
       // instead.
-      final MediaQueryData mediaQueryData = MediaQuery.of(context)!;
+      final MediaQueryData mediaQueryData = MediaQuery.of(context);
       text = MediaQuery(
         data: mediaQueryData.copyWith(
           textScaleFactor: math.min(1.0, mediaQueryData.textScaleFactor),
@@ -920,7 +920,7 @@ class _BottomNavigationBarState extends State<BottomNavigationBar> with TickerPr
     final BottomNavigationBarThemeData bottomTheme = BottomNavigationBarTheme.of(context);
 
     // Labels apply up to _bottomMargin padding. Remainder is media padding.
-    final double additionalBottomPadding = math.max(MediaQuery.of(context)!.padding.bottom - widget.selectedFontSize / 2.0, 0.0);
+    final double additionalBottomPadding = math.max(MediaQuery.of(context).padding.bottom - widget.selectedFontSize / 2.0, 0.0);
     Color? backgroundColor;
     switch (_effectiveType) {
       case BottomNavigationBarType.fixed:

packages/flutter/lib/src/material/bottom_sheet.dart

@@ -369,7 +369,7 @@ class _ModalBottomSheetState<T> extends State<_ModalBottomSheet<T>> {
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
     assert(debugCheckHasMaterialLocalizations(context));
-    final MediaQueryData? mediaQuery = MediaQuery.of(context);
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     final String routeLabel = _getRouteLabel(localizations);
 
@@ -395,7 +395,7 @@ class _ModalBottomSheetState<T> extends State<_ModalBottomSheet<T>> {
         // Disable the initial animation when accessible navigation is on so
         // that the semantics are added to the tree at the correct time.
         final double animationValue = animationCurve.transform(
-            mediaQuery!.accessibleNavigation ? 1.0 : widget.route!.animation!.value
+            mediaQuery.accessibleNavigation ? 1.0 : widget.route!.animation!.value
         );
         return Semantics(
           scopesRoute: true,

packages/flutter/lib/src/material/chip.dart

@@ -1829,7 +1829,7 @@ class _RawChipState extends State<RawChip> with TickerProviderStateMixin<RawChip
     final EdgeInsetsGeometry _defaultLabelPadding = EdgeInsets.lerp(
       const EdgeInsets.symmetric(horizontal: 8.0),
       const EdgeInsets.symmetric(horizontal: 4.0),
-      (MediaQuery.of(context)!.textScaleFactor - 1.0).clamp(0.0, 1.0),
+      (MediaQuery.of(context).textScaleFactor - 1.0).clamp(0.0, 1.0),
     )!;
 
     final ThemeData theme = Theme.of(context)!;

packages/flutter/lib/src/material/circle_avatar.dart

@@ -223,7 +223,7 @@ class CircleAvatar extends StatelessWidget {
               child: MediaQuery(
                 // Need to ignore the ambient textScaleFactor here so that the
                 // text doesn't escape the avatar when the textScaleFactor is large.
-                data: MediaQuery.of(context)!.copyWith(textScaleFactor: 1.0),
+                data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
                 child: IconTheme(
                   data: theme.iconTheme.copyWith(color: textStyle.color),
                   child: DefaultTextStyle(

packages/flutter/lib/src/material/dialog.dart

@@ -128,7 +128,7 @@ class Dialog extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final DialogTheme dialogTheme = DialogTheme.of(context);
-    final EdgeInsets effectivePadding = MediaQuery.of(context)!.viewInsets + (insetPadding ?? const EdgeInsets.all(0.0));
+    final EdgeInsets effectivePadding = MediaQuery.of(context).viewInsets + (insetPadding ?? const EdgeInsets.all(0.0));
     return AnimatedPadding(
       padding: effectivePadding,
       duration: insetAnimationDuration,
@@ -468,7 +468,7 @@ class AlertDialog extends StatelessWidget {
 
     // The paddingScaleFactor is used to adjust the padding of Dialog's
     // children.
-    final double paddingScaleFactor = _paddingScaleFactor(MediaQuery.of(context)!.textScaleFactor);
+    final double paddingScaleFactor = _paddingScaleFactor(MediaQuery.of(context).textScaleFactor);
     final TextDirection? textDirection = Directionality.maybeOf(context);
 
     Widget? titleWidget;
@@ -825,7 +825,7 @@ class SimpleDialog extends StatelessWidget {
 
     // The paddingScaleFactor is used to adjust the padding of Dialog
     // children.
-    final double paddingScaleFactor = _paddingScaleFactor(MediaQuery.of(context)!.textScaleFactor);
+    final double paddingScaleFactor = _paddingScaleFactor(MediaQuery.of(context).textScaleFactor);
     final TextDirection? textDirection = Directionality.maybeOf(context);
 
     Widget? titleWidget;

packages/flutter/lib/src/material/drawer.dart

@@ -498,7 +498,7 @@ class DrawerControllerState extends State<DrawerController> with SingleTickerPro
 
   Widget _buildDrawer(BuildContext context) {
     final bool drawerIsStart = widget.alignment == DrawerAlignment.start;
-    final EdgeInsets padding = MediaQuery.of(context)!.padding;
+    final EdgeInsets padding = MediaQuery.of(context).padding;
     final TextDirection textDirection = Directionality.of(context)!;
 
     double? dragAreaWidth = widget.edgeDragWidth;

packages/flutter/lib/src/material/drawer_header.dart

@@ -76,7 +76,7 @@ class DrawerHeader extends StatelessWidget {
     assert(debugCheckHasMaterial(context));
     assert(debugCheckHasMediaQuery(context));
     final ThemeData? theme = Theme.of(context);
-    final double statusBarHeight = MediaQuery.of(context)!.padding.top;
+    final double statusBarHeight = MediaQuery.of(context).padding.top;
     return Container(
       height: statusBarHeight + _kDrawerHeaderHeight,
       margin: margin,

packages/flutter/lib/src/material/dropdown.dart

@@ -1269,7 +1269,7 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
   bool get _enabled => widget.items != null && widget.items!.isNotEmpty && widget.onChanged != null;
 
   Orientation _getOrientation(BuildContext context) {
-    Orientation? result = MediaQuery.of(context, nullOk: true)?.orientation;
+    Orientation? result = MediaQuery.maybeOf(context)?.orientation;
     if (result == null) {
       // If there's no MediaQuery, then use the window aspect to determine
       // orientation.

packages/flutter/lib/src/material/elevated_button.dart

@@ -255,7 +255,7 @@ class ElevatedButton extends ButtonStyleButton {
       const EdgeInsets.symmetric(horizontal: 16),
       const EdgeInsets.symmetric(horizontal: 8),
       const EdgeInsets.symmetric(horizontal: 4),
-      MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1,
+      MediaQuery.maybeOf(context)?.textScaleFactor ?? 1,
     );
 
     return styleFrom(
@@ -397,7 +397,7 @@ class _ElevatedButtonWithIcon extends ElevatedButton {
       const EdgeInsetsDirectional.fromSTEB(12, 0, 16, 0),
       const EdgeInsets.symmetric(horizontal: 8),
       const EdgeInsetsDirectional.fromSTEB(8, 0, 4, 0),
-      MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1,
+      MediaQuery.maybeOf(context)?.textScaleFactor ?? 1,
     );
     return super.defaultStyleOf(context).copyWith(
       padding: MaterialStateProperty.all<EdgeInsetsGeometry>(scaledPadding)
@@ -413,7 +413,7 @@ class _ElevatedButtonWithIconChild extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final double scale = MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1;
+    final double scale = MediaQuery.maybeOf(context)?.textScaleFactor ?? 1;
     final double gap = scale <= 1 ? 8 : lerpDouble(8, 4, math.min(scale - 1, 1))!;
     return Row(
       mainAxisSize: MainAxisSize.min,

packages/flutter/lib/src/material/ink_well.dart

@@ -916,7 +916,7 @@ class _InkResponseState extends State<_InkResponseStateWidget>
   }
 
   bool get _shouldShowFocus {
-    final NavigationMode mode = MediaQuery.of(context, nullOk: true)?.navigationMode ?? NavigationMode.traditional;
+    final NavigationMode mode = MediaQuery.maybeOf(context)?.navigationMode ?? NavigationMode.traditional;
     switch (mode) {
       case NavigationMode.traditional:
         return enabled && _hasFocus;
@@ -1055,7 +1055,7 @@ class _InkResponseState extends State<_InkResponseStateWidget>
   }
 
   bool get _canRequestFocus {
-    final NavigationMode mode = MediaQuery.of(context, nullOk: true)?.navigationMode ?? NavigationMode.traditional;
+    final NavigationMode mode = MediaQuery.maybeOf(context)?.navigationMode ?? NavigationMode.traditional;
     switch (mode) {
       case NavigationMode.traditional:
         return enabled && widget.canRequestFocus;

packages/flutter/lib/src/material/outlined_button.dart

@@ -226,7 +226,7 @@ class OutlinedButton extends ButtonStyleButton {
       const EdgeInsets.symmetric(horizontal: 16),
       const EdgeInsets.symmetric(horizontal: 8),
       const EdgeInsets.symmetric(horizontal: 4),
-      MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1,
+      MediaQuery.maybeOf(context)?.textScaleFactor ?? 1,
     );
 
     return styleFrom(
@@ -341,7 +341,7 @@ class _OutlinedButtonWithIconChild extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final double scale = MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1;
+    final double scale = MediaQuery.maybeOf(context)?.textScaleFactor ?? 1;
     final double gap = scale <= 1 ? 8 : lerpDouble(8, 4, math.min(scale - 1, 1))!;
     return Row(
       mainAxisSize: MainAxisSize.min,

packages/flutter/lib/src/material/pickers/calendar_date_range_picker.dart

@@ -436,7 +436,7 @@ class _DayHeaders extends StatelessWidget {
 
     return Container(
       constraints: BoxConstraints(
-        maxWidth: MediaQuery.of(context)!.orientation == Orientation.landscape
+        maxWidth: MediaQuery.of(context).orientation == Orientation.landscape
           ? _maxCalendarWidthLandscape
           : _maxCalendarWidthPortrait,
         maxHeight: _monthItemRowHeight,
@@ -888,7 +888,7 @@ class _MonthItemState extends State<_MonthItem> {
       paddedDayItems.addAll(weekList);
     }
 
-    final double maxWidth = MediaQuery.of(context)!.orientation == Orientation.landscape
+    final double maxWidth = MediaQuery.of(context).orientation == Orientation.landscape
       ? _maxCalendarWidthLandscape
       : _maxCalendarWidthPortrait;
     return Column(

packages/flutter/lib/src/material/pickers/date_picker_dialog.dart

@@ -331,7 +331,7 @@ class _DatePickerDialogState extends State<_DatePickerDialog> {
   }
 
   Size _dialogSize(BuildContext context) {
-    final Orientation orientation = MediaQuery.of(context)!.orientation;
+    final Orientation orientation = MediaQuery.of(context).orientation;
     switch (_entryMode) {
       case DatePickerEntryMode.calendar:
         switch (orientation) {
@@ -360,11 +360,11 @@ class _DatePickerDialogState extends State<_DatePickerDialog> {
     final ThemeData theme = Theme.of(context)!;
     final ColorScheme colorScheme = theme.colorScheme;
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
-    final Orientation orientation = MediaQuery.of(context)!.orientation;
+    final Orientation orientation = MediaQuery.of(context).orientation;
     final TextTheme textTheme = theme.textTheme;
     // Constrain the textScaleFactor to the largest supported value to prevent
     // layout issues.
-    final double textScaleFactor = math.min(MediaQuery.of(context)!.textScaleFactor, 1.3);
+    final double textScaleFactor = math.min(MediaQuery.of(context).textScaleFactor, 1.3);
 
     final String dateText = localizations.formatMediumDate(_selectedDate);
     final Color dateColor = colorScheme.brightness == Brightness.light
@@ -467,7 +467,7 @@ class _DatePickerDialogState extends State<_DatePickerDialog> {
         duration: _dialogSizeAnimationDuration,
         curve: Curves.easeIn,
         child: MediaQuery(
-          data: MediaQuery.of(context)!.copyWith(
+          data: MediaQuery.of(context).copyWith(
             textScaleFactor: textScaleFactor,
           ),
           child: Builder(builder: (BuildContext context) {

packages/flutter/lib/src/material/pickers/date_range_picker_dialog.dart

@@ -335,7 +335,7 @@ class _DateRangePickerDialogState extends State<_DateRangePickerDialog> {
 
   @override
   Widget build(BuildContext context) {
-    final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
     final Orientation orientation = mediaQuery.orientation;
     final double textScaleFactor = math.min(mediaQuery.textScaleFactor, 1.3);
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
@@ -428,7 +428,7 @@ class _DateRangePickerDialogState extends State<_DateRangePickerDialog> {
         duration: _dialogSizeAnimationDuration,
         curve: Curves.easeIn,
         child: MediaQuery(
-          data: MediaQuery.of(context)!.copyWith(
+          data: MediaQuery.of(context).copyWith(
             textScaleFactor: textScaleFactor,
           ),
           child: Builder(builder: (BuildContext context) {
@@ -479,7 +479,7 @@ class _CalendarRangePickerDialog extends StatelessWidget {
     final ThemeData theme = Theme.of(context)!;
     final ColorScheme colorScheme = theme.colorScheme;
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
-    final Orientation orientation = MediaQuery.of(context)!.orientation;
+    final Orientation orientation = MediaQuery.of(context).orientation;
     final TextTheme textTheme = theme.textTheme;
     final Color headerForeground = colorScheme.brightness == Brightness.light
       ? colorScheme.onPrimary
@@ -525,7 +525,7 @@ class _CalendarRangePickerDialog extends StatelessWidget {
           ],
           bottom: PreferredSize(
             child: Row(children: <Widget>[
-              SizedBox(width: MediaQuery.of(context)!.size.width < 360 ? 42 : 72),
+              SizedBox(width: MediaQuery.of(context).size.width < 360 ? 42 : 72),
               Expanded(
                 child: Semantics(
                   label: '$helpText $startDateText to $endDateText',
@@ -633,7 +633,7 @@ class _InputDateRangePickerDialog extends StatelessWidget {
     final ThemeData theme = Theme.of(context)!;
     final ColorScheme colorScheme = theme.colorScheme;
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
-    final Orientation orientation = MediaQuery.of(context)!.orientation;
+    final Orientation orientation = MediaQuery.of(context).orientation;
     final TextTheme textTheme = theme.textTheme;
 
     final Color dateColor = colorScheme.brightness == Brightness.light

packages/flutter/lib/src/material/popup_menu.dart

@@ -1098,7 +1098,7 @@ class PopupMenuButtonState<T> extends State<PopupMenuButton<T>> {
   }
 
   bool get _canRequestFocus {
-    final NavigationMode mode = MediaQuery.of(context, nullOk: true)?.navigationMode ?? NavigationMode.traditional;
+    final NavigationMode mode = MediaQuery.maybeOf(context)?.navigationMode ?? NavigationMode.traditional;
     switch (mode) {
       case NavigationMode.traditional:
         return widget.enabled;

packages/flutter/lib/src/material/range_slider.dart

@@ -637,7 +637,7 @@ class _RangeSliderState extends State<RangeSlider> with TickerProviderStateMixin
     // This size is used as the max bounds for the painting of the value
     // indicators. It must be kept in sync with the function with the same name
     // in slider.dart.
-    Size _screenSize() => MediaQuery.of(context)!.size;
+    Size _screenSize() => MediaQuery.of(context).size;
 
     return CompositedTransformTarget(
       link: _layerLink,
@@ -646,7 +646,7 @@ class _RangeSliderState extends State<RangeSlider> with TickerProviderStateMixin
         divisions: widget.divisions,
         labels: widget.labels,
         sliderTheme: sliderTheme,
-        textScaleFactor: MediaQuery.of(context)!.textScaleFactor,
+        textScaleFactor: MediaQuery.of(context).textScaleFactor,
         screenSize: _screenSize(),
         onChanged: (widget.onChanged != null) && (widget.max > widget.min) ? _handleChanged : null,
         onChangeStart: widget.onChangeStart != null ? _handleDragStart : null,

packages/flutter/lib/src/material/scaffold.dart

@@ -240,7 +240,7 @@ class ScaffoldMessengerState extends State<ScaffoldMessenger> with TickerProvide
 
   @override
   void didChangeDependencies() {
-    final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
     // If we transition from accessible navigation to non-accessible navigation
     // and there is a SnackBar that would have timed out that has already
     // completed its timer, dismiss that SnackBar. If the timer hasn't finished
@@ -406,7 +406,7 @@ class ScaffoldMessengerState extends State<ScaffoldMessenger> with TickerProvide
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
     _accessibleNavigation = mediaQuery.accessibleNavigation;
 
     if (_snackBars.isNotEmpty) {
@@ -418,7 +418,7 @@ class ScaffoldMessengerState extends State<ScaffoldMessenger> with TickerProvide
             assert(_snackBarController!.status == AnimationStatus.forward ||
                    _snackBarController!.status == AnimationStatus.completed);
             // Look up MediaQuery again in case the setting changed.
-            final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+            final MediaQueryData mediaQuery = MediaQuery.of(context);
             if (mediaQuery.accessibleNavigation && snackBar.action != null)
               return;
             hideCurrentSnackBar(reason: SnackBarClosedReason.timeout);
@@ -769,7 +769,7 @@ class _BodyBuilder extends StatelessWidget {
     return LayoutBuilder(
       builder: (BuildContext context, BoxConstraints constraints) {
         final _BodyBoxConstraints bodyConstraints = constraints as _BodyBoxConstraints;
-        final MediaQueryData metrics = MediaQuery.of(context)!;
+        final MediaQueryData metrics = MediaQuery.of(context);
 
         final double bottom = extendBody
           ? math.max(metrics.padding.bottom, bodyConstraints.bottomWidgetsHeight)
@@ -2281,7 +2281,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin {
 
     if (_snackBars.isEmpty || _snackBarController!.status == AnimationStatus.dismissed)
       return;
-    final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
     final Completer<SnackBarClosedReason> completer = _snackBars.first._completer;
     if (mediaQuery.accessibleNavigation) {
       _snackBarController!.value = 0.0;
@@ -2725,7 +2725,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin {
     _scaffoldMessenger?._register(this);
 
     // TODO(Piinks): Remove old SnackBar API after migrating ScaffoldMessenger
-    final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
     // If we transition from accessible navigation to non-accessible navigation
     // and there is a SnackBar that would have timed out that has already
     // completed its timer, dismiss that SnackBar. If the timer hasn't finished
@@ -2773,7 +2773,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin {
     bool removeBottomInset = false,
     bool maintainBottomViewPadding = false,
   }) {
-    MediaQueryData data = MediaQuery.of(context)!.removePadding(
+    MediaQueryData data = MediaQuery.of(context).removePadding(
       removeLeft: removeLeftPadding,
       removeTop: removeTopPadding,
       removeRight: removeRightPadding,
@@ -2869,7 +2869,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin {
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
     assert(debugCheckHasDirectionality(context));
-    final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+    final MediaQueryData mediaQuery = MediaQuery.of(context);
     final ThemeData themeData = Theme.of(context)!;
     final TextDirection textDirection = Directionality.of(context)!;
 
@@ -2884,7 +2884,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin {
             assert(_snackBarController!.status == AnimationStatus.forward ||
                    _snackBarController!.status == AnimationStatus.completed);
             // Look up MediaQuery again in case the setting changed.
-            final MediaQueryData mediaQuery = MediaQuery.of(context)!;
+            final MediaQueryData mediaQuery = MediaQuery.of(context);
             if (mediaQuery.accessibleNavigation && snackBar.action != null)
               return;
             hideCurrentSnackBar(reason: SnackBarClosedReason.timeout);

packages/flutter/lib/src/material/scrollbar.dart

@@ -167,7 +167,7 @@ class _ScrollbarState extends State<Scrollbar> with SingleTickerProviderStateMix
       thickness: widget.thickness ?? _kScrollbarThickness,
       radius: widget.radius,
       fadeoutOpacityAnimation: _fadeoutOpacityAnimation,
-      padding: MediaQuery.of(context)!.padding,
+      padding: MediaQuery.of(context).padding,
     );
   }
 

packages/flutter/lib/src/material/selectable_text.dart

@@ -590,7 +590,7 @@ class _SelectableTextState extends State<SelectableText> with AutomaticKeepAlive
         cursorColor ??= selectionTheme.cursorColor ?? cupertinoTheme.primaryColor;
         selectionColor = selectionTheme.selectionColor ?? cupertinoTheme.primaryColor.withOpacity(0.40);
         cursorRadius ??= const Radius.circular(2.0);
-        cursorOffset = Offset(iOSHorizontalOffset / MediaQuery.of(context)!.devicePixelRatio, 0);
+        cursorOffset = Offset(iOSHorizontalOffset / MediaQuery.of(context).devicePixelRatio, 0);
         break;
 
       case TargetPlatform.android:

packages/flutter/lib/src/material/slider.dart

@@ -703,7 +703,7 @@ class _SliderState extends State<Slider> with TickerProviderStateMixin {
     // This size is used as the max bounds for the painting of the value
     // indicators It must be kept in sync with the function with the same name
     // in range_slider.dart.
-    Size _screenSize() => MediaQuery.of(context)!.size;
+    Size _screenSize() => MediaQuery.of(context).size;
 
     return Semantics(
       container: true,
@@ -725,7 +725,7 @@ class _SliderState extends State<Slider> with TickerProviderStateMixin {
             divisions: widget.divisions,
             label: widget.label,
             sliderTheme: sliderTheme,
-            textScaleFactor: MediaQuery.of(context)!.textScaleFactor,
+            textScaleFactor: MediaQuery.of(context).textScaleFactor,
             screenSize: _screenSize(),
             onChanged: (widget.onChanged != null) && (widget.max > widget.min) ? _handleChanged : null,
             onChangeStart: widget.onChangeStart != null ? _handleDragStart : null,

packages/flutter/lib/src/material/snack_bar.dart

@@ -383,7 +383,7 @@ class _SnackBarState extends State<SnackBar> {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final MediaQueryData mediaQueryData = MediaQuery.of(context)!;
+    final MediaQueryData mediaQueryData = MediaQuery.of(context);
     assert(widget.animation != null);
     final ThemeData theme = Theme.of(context)!;
     final ColorScheme colorScheme = theme.colorScheme;

packages/flutter/lib/src/material/text_button.dart

@@ -242,7 +242,7 @@ class TextButton extends ButtonStyleButton {
       const EdgeInsets.all(8),
       const EdgeInsets.symmetric(horizontal: 8),
       const EdgeInsets.symmetric(horizontal: 4),
-      MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1,
+      MediaQuery.maybeOf(context)?.textScaleFactor ?? 1,
     );
 
     return styleFrom(
@@ -359,7 +359,7 @@ class _TextButtonWithIcon extends TextButton {
       const EdgeInsets.all(8),
       const EdgeInsets.symmetric(horizontal: 4),
       const EdgeInsets.symmetric(horizontal: 4),
-      MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1,
+      MediaQuery.maybeOf(context)?.textScaleFactor ?? 1,
     );
     return super.defaultStyleOf(context).copyWith(
       padding: MaterialStateProperty.all<EdgeInsetsGeometry>(scaledPadding)
@@ -379,7 +379,7 @@ class _TextButtonWithIconChild extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final double scale = MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1;
+    final double scale = MediaQuery.maybeOf(context)?.textScaleFactor ?? 1;
     final double gap = scale <= 1 ? 8 : lerpDouble(8, 4, math.min(scale - 1, 1))!;
     return Row(
       mainAxisSize: MainAxisSize.min,

packages/flutter/lib/src/material/text_field.dart

@@ -1059,7 +1059,7 @@ class _TextFieldState extends State<TextField> with RestorationMixin implements
   }
 
   bool get _canRequestFocus {
-    final NavigationMode mode = MediaQuery.of(context, nullOk: true)?.navigationMode ?? NavigationMode.traditional;
+    final NavigationMode mode = MediaQuery.maybeOf(context)?.navigationMode ?? NavigationMode.traditional;
     switch (mode) {
       case NavigationMode.traditional:
         return _isEnabled;
@@ -1285,7 +1285,7 @@ class _TextFieldState extends State<TextField> with RestorationMixin implements
         cursorColor ??= selectionTheme.cursorColor ?? cupertinoTheme.primaryColor;
         selectionColor = selectionTheme.selectionColor ?? cupertinoTheme.primaryColor.withOpacity(0.40);
         cursorRadius ??= const Radius.circular(2.0);
-        cursorOffset = Offset(iOSHorizontalOffset / MediaQuery.of(context)!.devicePixelRatio, 0);
+        cursorOffset = Offset(iOSHorizontalOffset / MediaQuery.of(context).devicePixelRatio, 0);
         autocorrectionTextRectColor = selectionColor;
         break;
 

packages/flutter/lib/src/material/text_selection.dart

@@ -760,7 +760,7 @@ class _MaterialTextSelectionControls extends TextSelectionControls {
     const double closedToolbarHeightNeeded = _kToolbarScreenPadding
       + _kToolbarHeight
       + _kToolbarContentDistance;
-    final double paddingTop = MediaQuery.of(context)!.padding.top;
+    final double paddingTop = MediaQuery.of(context).padding.top;
     final double availableHeight = globalEditableRegion.top
       + startTextSelectionPoint.point.dy
       - textLineHeight

packages/flutter/lib/src/material/time.dart

@@ -107,7 +107,7 @@ class TimeOfDay {
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     return localizations.formatTimeOfDay(
       this,
-      alwaysUse24HourFormat: MediaQuery.of(context)!.alwaysUse24HourFormat,
+      alwaysUse24HourFormat: MediaQuery.of(context).alwaysUse24HourFormat,
     );
   }
 

packages/flutter/lib/src/material/time_picker.dart

@@ -135,7 +135,7 @@ class _TimePickerHeader extends StatelessWidget {
     assert(debugCheckHasMediaQuery(context));
     final ThemeData themeData = Theme.of(context)!;
     final TimeOfDayFormat timeOfDayFormat = MaterialLocalizations.of(context).timeOfDayFormat(
-      alwaysUse24HourFormat: MediaQuery.of(context)!.alwaysUse24HourFormat,
+      alwaysUse24HourFormat: MediaQuery.of(context).alwaysUse24HourFormat,
     );
 
     final _TimePickerFragmentContext fragmentContext = _TimePickerFragmentContext(
@@ -321,7 +321,7 @@ class _HourControl extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final bool alwaysUse24HourFormat = MediaQuery.of(context)!.alwaysUse24HourFormat;
+    final bool alwaysUse24HourFormat = MediaQuery.of(context).alwaysUse24HourFormat;
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     final String formattedHour = localizations.formatHour(
       fragmentContext.selectedTime,
@@ -563,7 +563,7 @@ class _DayPeriodControl extends StatelessWidget {
       side: borderSide,
     );
 
-    final double buttonTextScaleFactor = math.min(MediaQuery.of(context)!.textScaleFactor, 2.0);
+    final double buttonTextScaleFactor = math.min(MediaQuery.of(context).textScaleFactor, 2.0);
 
     final Widget amButton = Material(
       color: MaterialStateProperty.resolveAs(backgroundColor, amStates),
@@ -942,7 +942,7 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
     assert(debugCheckHasMediaQuery(context));
     themeData = Theme.of(context)!;
     localizations = MaterialLocalizations.of(context);
-    media = MediaQuery.of(context)!;
+    media = MediaQuery.of(context);
   }
 
   @override
@@ -1152,7 +1152,7 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
 
   _TappableLabel _buildTappableLabel(TextTheme textTheme, Color color, int value, String label, VoidCallback onTap) {
     final TextStyle style = textTheme.bodyText1!.copyWith(color: color);
-    final double labelScaleFactor = math.min(MediaQuery.of(context)!.textScaleFactor, 2.0);
+    final double labelScaleFactor = math.min(MediaQuery.of(context).textScaleFactor, 2.0);
     return _TappableLabel(
       value: value,
       painter: TextPainter(
@@ -1322,7 +1322,7 @@ class _TimePickerInputState extends State<_TimePickerInput> {
       return null;
     }
 
-    if (MediaQuery.of(context)!.alwaysUse24HourFormat) {
+    if (MediaQuery.of(context).alwaysUse24HourFormat) {
       if (newHour >= 0 && newHour < 24) {
         return newHour;
       }
@@ -1408,7 +1408,7 @@ class _TimePickerInputState extends State<_TimePickerInput> {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final MediaQueryData media = MediaQuery.of(context)!;
+    final MediaQueryData media = MediaQuery.of(context);
     final TimeOfDayFormat timeOfDayFormat = MaterialLocalizations.of(context).timeOfDayFormat(alwaysUse24HourFormat: media.alwaysUse24HourFormat);
     final bool use24HourDials = hourFormat(of: timeOfDayFormat) != HourFormat.h;
     final ThemeData theme = Theme.of(context)!;
@@ -1631,7 +1631,7 @@ class _HourMinuteTextFieldState extends State<_HourMinuteTextField> {
   }
 
   String get _formattedValue {
-    final bool alwaysUse24HourFormat = MediaQuery.of(context)!.alwaysUse24HourFormat;
+    final bool alwaysUse24HourFormat = MediaQuery.of(context).alwaysUse24HourFormat;
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     return !widget.isHour ? localizations.formatMinute(widget.selectedTime) : localizations.formatHour(
       widget.selectedTime,
@@ -1677,7 +1677,7 @@ class _HourMinuteTextFieldState extends State<_HourMinuteTextField> {
     //
     // TODO(rami-a): Once https://github.com/flutter/flutter/issues/67571 is
     // resolved, remove the window check for semantics being enabled on web.
-    final String? hintText = MediaQuery.of(context)!.accessibleNavigation || ui.window.semanticsEnabled
+    final String? hintText = MediaQuery.of(context).accessibleNavigation || ui.window.semanticsEnabled
         ? widget.semanticHintText
         : (focusNode.hasFocus ? null : _formattedValue);
     inputDecoration = inputDecoration.copyWith(
@@ -1688,7 +1688,7 @@ class _HourMinuteTextFieldState extends State<_HourMinuteTextField> {
     return SizedBox(
       height: _kTimePickerHeaderControlHeight,
       child: MediaQuery(
-        data: MediaQuery.of(context)!.copyWith(textScaleFactor: 1.0),
+        data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
         child: TextFormField(
           autofocus: widget.autofocus ?? false,
           expands: true,
@@ -1854,7 +1854,7 @@ class _TimePickerDialogState extends State<_TimePickerDialog> {
     if (_announcedInitialTime)
       return;
 
-    final MediaQueryData media = MediaQuery.of(context)!;
+    final MediaQueryData media = MediaQuery.of(context);
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     _announceToAccessibility(
       context,
@@ -1903,12 +1903,12 @@ class _TimePickerDialogState extends State<_TimePickerDialog> {
   }
 
   Size _dialogSize(BuildContext context) {
-    final Orientation orientation = MediaQuery.of(context)!.orientation;
+    final Orientation orientation = MediaQuery.of(context).orientation;
     final ThemeData theme = Theme.of(context)!;
     // Constrain the textScaleFactor to prevent layout issues. Since only some
     // parts of the time picker scale up with textScaleFactor, we cap the factor
     // to 1.1 as that provides enough space to reasonably fit all the content.
-    final double textScaleFactor = math.min(MediaQuery.of(context)!.textScaleFactor, 1.1);
+    final double textScaleFactor = math.min(MediaQuery.of(context).textScaleFactor, 1.1);
 
     final double timePickerWidth;
     final double timePickerHeight;
@@ -1940,7 +1940,7 @@ class _TimePickerDialogState extends State<_TimePickerDialog> {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final MediaQueryData media = MediaQuery.of(context)!;
+    final MediaQueryData media = MediaQuery.of(context);
     final TimeOfDayFormat timeOfDayFormat = localizations.timeOfDayFormat(alwaysUse24HourFormat: media.alwaysUse24HourFormat);
     final bool use24HourDials = hourFormat(of: timeOfDayFormat) != HourFormat.h;
     final ThemeData theme = Theme.of(context)!;

packages/flutter/lib/src/widgets/actions.dart

@@ -1057,7 +1057,7 @@ class _FocusableActionDetectorState extends State<FocusableActionDetector> {
     }
 
     bool canRequestFocus(FocusableActionDetector target) {
-      final NavigationMode mode = MediaQuery.of(context, nullOk: true)?.navigationMode ?? NavigationMode.traditional;
+      final NavigationMode mode = MediaQuery.maybeOf(context)?.navigationMode ?? NavigationMode.traditional;
       switch (mode) {
         case NavigationMode.traditional:
           return target.enabled;
@@ -1098,7 +1098,7 @@ class _FocusableActionDetectorState extends State<FocusableActionDetector> {
   }
 
   bool get _canRequestFocus {
-    final NavigationMode mode = MediaQuery.of(context, nullOk: true)?.navigationMode ?? NavigationMode.traditional;
+    final NavigationMode mode = MediaQuery.maybeOf(context)?.navigationMode ?? NavigationMode.traditional;
     switch (mode) {
       case NavigationMode.traditional:
         return widget.enabled;

packages/flutter/lib/src/widgets/debug.dart

@@ -216,13 +216,16 @@ bool debugCheckHasMediaQuery(BuildContext context) {
   assert(() {
     if (context.widget is! MediaQuery && context.findAncestorWidgetOfExactType<MediaQuery>() == null) {
       throw FlutterError.fromParts(<DiagnosticsNode>[
-        ErrorSummary('No MediaQuery widget found.'),
+        ErrorSummary('No MediaQuery widget ancestor found.'),
         ErrorDescription('${context.widget.runtimeType} widgets require a MediaQuery widget ancestor.'),
         context.describeWidget('The specific widget that could not find a MediaQuery ancestor was'),
         context.describeOwnershipChain('The ownership chain for the affected widget is'),
         ErrorHint(
-          'Typically, the MediaQuery widget is introduced by the MaterialApp or '
+          'No MediaQuery ancestor could be found starting from the context '
-          'WidgetsApp widget at the top of your application widget tree.'
+          'that was passed to MediaQuery.of(). This can happen because you '
+          'have not added a WidgetsApp, CupertinoApp, or MaterialApp widget '
+          '(those widgets introduce a MediaQuery), or it can happen if the '
+          'context you use comes from a widget above those widgets.'
         ),
       ]);
     }

packages/flutter/lib/src/widgets/editable_text.dart

@@ -2443,7 +2443,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   @override
   TextEditingValue get textEditingValue => _value;
 
-  double get _devicePixelRatio => MediaQuery.of(context)?.devicePixelRatio ?? 1.0;
+  double get _devicePixelRatio => MediaQuery.of(context).devicePixelRatio;
 
   @override
   set textEditingValue(TextEditingValue value) {

packages/flutter/lib/src/widgets/image.dart

@@ -50,7 +50,7 @@ export 'package:flutter/painting.dart' show
 ImageConfiguration createLocalImageConfiguration(BuildContext context, { Size? size }) {
   return ImageConfiguration(
     bundle: DefaultAssetBundle.of(context),
-    devicePixelRatio: MediaQuery.of(context, nullOk: true)?.devicePixelRatio ?? 1.0,
+    devicePixelRatio: MediaQuery.maybeOf(context)?.devicePixelRatio ?? 1.0,
     locale: Localizations.localeOf(context, nullOk: true),
     textDirection: Directionality.maybeOf(context),
     size: size,
@@ -1145,7 +1145,7 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
   }
 
   void _updateInvertColors() {
-    _invertColors = MediaQuery.of(context, nullOk: true)?.invertColors
+    _invertColors = MediaQuery.maybeOf(context)?.invertColors
         ?? SemanticsBinding.instance!.accessibilityFeatures.invertColors;
   }
 

packages/flutter/lib/src/widgets/media_query.dart

@@ -9,6 +9,7 @@ import 'dart:ui' show Brightness;
 import 'package:flutter/foundation.dart';
 
 import 'basic.dart';
+import 'debug.dart';
 import 'framework.dart';
 
 /// Whether in portrait or landscape.
@@ -683,7 +684,7 @@ class MediaQuery extends InheritedWidget {
   }) {
     return MediaQuery(
       key: key,
-      data: MediaQuery.of(context)!.removePadding(
+      data: MediaQuery.of(context).removePadding(
         removeLeft: removeLeft,
         removeTop: removeTop,
         removeRight: removeRight,
@@ -728,7 +729,7 @@ class MediaQuery extends InheritedWidget {
   }) {
     return MediaQuery(
       key: key,
-      data: MediaQuery.of(context)!.removeViewInsets(
+      data: MediaQuery.of(context).removeViewInsets(
         removeLeft: removeLeft,
         removeTop: removeTop,
         removeRight: removeRight,
@@ -772,7 +773,7 @@ class MediaQuery extends InheritedWidget {
   }) {
     return MediaQuery(
       key: key,
-      data: MediaQuery.of(context)!.removeViewPadding(
+      data: MediaQuery.of(context).removeViewPadding(
         removeLeft: removeLeft,
         removeTop: removeTop,
         removeRight: removeRight,
@@ -791,9 +792,10 @@ class MediaQuery extends InheritedWidget {
   /// The data from the closest instance of this class that encloses the given
   /// context.
   ///
-  /// You can use this function to query the size an orientation of the screen.
+  /// You can use this function to query the size and orientation of the screen,
-  /// When that information changes, your widget will be scheduled to be
+  /// as well as other media parameters (see [MediaQueryData] for more
-  /// rebuilt, keeping your widget up-to-date.
+  /// examples). When that information changes, your widget will be scheduled to
+  /// be rebuilt, keeping your widget up-to-date.
   ///
   /// Typical usage is as follows:
   ///
@@ -801,35 +803,56 @@ class MediaQuery extends InheritedWidget {
   /// MediaQueryData media = MediaQuery.of(context);
   /// ```
   ///
-  /// If there is no [MediaQuery] in scope, then this will throw an exception.
+  /// If there is no [MediaQuery] in scope, this will throw a [TypeError]
-  /// To return null if there is no [MediaQuery], then pass `nullOk: true`.
+  /// exception in release builds, and throw a descriptive [FlutterError] in
+  /// debug builds.
   ///
-  /// If you use this from a widget (e.g. in its build function), consider
+  /// See also:
-  /// calling [debugCheckHasMediaQuery].
+  ///
-  static MediaQueryData? of(BuildContext context, { bool nullOk = false }) {
+  ///  * [maybeOf], which doesn't throw or assert if it doesn't find a
+  ///    [MediaQuery] ancestor, it returns null instead.
+  static MediaQueryData of(BuildContext context) {
     assert(context != null);
-    assert(nullOk != null);
+    assert(debugCheckHasMediaQuery(context));
-    final MediaQuery? query = context.dependOnInheritedWidgetOfExactType<MediaQuery>();
+    return context.dependOnInheritedWidgetOfExactType<MediaQuery>()!.data;
-    if (query != null)
+  }
-      return query.data;
+
-    if (nullOk)
+  /// The data from the closest instance of this class that encloses the given
-      return null;
+  /// context, if any.
-    throw FlutterError.fromParts(<DiagnosticsNode>[
+  ///
-      ErrorSummary('MediaQuery.of() called with a context that does not contain a MediaQuery.'),
+  /// Use this function if you want to allow situations where no [MediaQuery] is
-      ErrorDescription(
+  /// in scope. Prefer using [MediaQuery.of] in situations where a media query
-        'No MediaQuery ancestor could be found starting from the context that was passed '
+  /// is always expected to exist.
-        'to MediaQuery.of(). This can happen because you do not have a WidgetsApp or '
+  ///
-        'MaterialApp widget (those widgets introduce a MediaQuery), or it can happen '
+  /// If there is no [MediaQuery] in scope, then this function will return null.
-        'if the context you use comes from a widget above those widgets.'
+  ///
-      ),
+  /// You can use this function to query the size and orientation of the screen,
-      context.describeElement('The context used was')
+  /// as well as other media parameters (see [MediaQueryData] for more
-    ]);
+  /// examples). When that information changes, your widget will be scheduled to
+  /// be rebuilt, keeping your widget up-to-date.
+  ///
+  /// Typical usage is as follows:
+  ///
+  /// ```dart
+  /// MediaQueryData? mediaQuery = MediaQuery.maybeOf(context);
+  /// if (mediaQuery == null) {
+  ///   // Do something else instead.
+  /// }
+  /// ```
+  ///
+  /// See also:
+  ///
+  ///  * [of], which will throw if it doesn't find a [MediaQuery] ancestor,
+  ///    instead of returning null.
+  static MediaQueryData? maybeOf(BuildContext context) {
+    assert(context != null);
+    return context.dependOnInheritedWidgetOfExactType<MediaQuery>()?.data;
   }
 
   /// Returns textScaleFactor for the nearest MediaQuery ancestor or 1.0, if
   /// no such ancestor exists.
   static double textScaleFactorOf(BuildContext context) {
-    return MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1.0;
+    return MediaQuery.maybeOf(context)?.textScaleFactor ?? 1.0;
   }
 
   /// Returns platformBrightness for the nearest MediaQuery ancestor or
@@ -838,7 +861,7 @@ class MediaQuery extends InheritedWidget {
   /// Use of this method will cause the given [context] to rebuild any time that
   /// any property of the ancestor [MediaQuery] changes.
   static Brightness platformBrightnessOf(BuildContext context) {
-    return MediaQuery.of(context, nullOk: true)?.platformBrightness ?? Brightness.light;
+    return MediaQuery.maybeOf(context)?.platformBrightness ?? Brightness.light;
   }
 
   /// Returns highContrast for the nearest MediaQuery ancestor or false, if no
@@ -849,13 +872,13 @@ class MediaQuery extends InheritedWidget {
   ///  * [MediaQueryData.highContrast], which indicates the platform's
   ///    desire to increase contrast.
   static bool highContrastOf(BuildContext context) {
-    return MediaQuery.of(context, nullOk: true)?.highContrast ?? false;
+    return MediaQuery.maybeOf(context)?.highContrast ?? false;
   }
 
   /// Returns the boldText accessibility setting for the nearest MediaQuery
   /// ancestor, or false if no such ancestor exists.
   static bool boldTextOverride(BuildContext context) {
-    return MediaQuery.of(context, nullOk: true)?.boldText ?? false;
+    return MediaQuery.maybeOf(context)?.boldText ?? false;
   }
 
   @override

packages/flutter/lib/src/widgets/safe_area.dart

@@ -95,7 +95,7 @@ class SafeArea extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final MediaQueryData data = MediaQuery.of(context)!;
+    final MediaQueryData data = MediaQuery.of(context);
     EdgeInsets padding = data.padding;
     // Bottom padding has been consumed - i.e. by the keyboard
     if (data.padding.bottom == 0.0 && data.viewInsets.bottom != 0.0 && maintainBottomViewPadding)
@@ -194,7 +194,7 @@ class SliverSafeArea extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final EdgeInsets padding = MediaQuery.of(context)!.padding;
+    final EdgeInsets padding = MediaQuery.of(context).padding;
     return SliverPadding(
       padding: EdgeInsets.only(
         left: math.max(left ? padding.left : 0.0, minimum.left),

packages/flutter/lib/src/widgets/scroll_view.dart

@@ -675,7 +675,7 @@ abstract class BoxScrollView extends ScrollView {
     Widget sliver = buildChildLayout(context);
     EdgeInsetsGeometry? effectivePadding = padding;
     if (padding == null) {
-      final MediaQueryData? mediaQuery = MediaQuery.of(context, nullOk: true);
+      final MediaQueryData? mediaQuery = MediaQuery.maybeOf(context);
       if (mediaQuery != null) {
         // Automatically pad sliver with padding from MediaQuery.
         final EdgeInsets mediaQueryHorizontalPadding =

packages/flutter/test/cupertino/action_sheet_test.dart

@@ -283,7 +283,7 @@ void main() {
       createAppWithButtonThatLaunchesActionSheet(
         Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
             child: CupertinoActionSheet(
               title: const Text('The title'),
               message: const Text('The message.'),
@@ -348,9 +348,9 @@ void main() {
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesActionSheet(
         Builder(builder: (BuildContext context) {
-          screenHeight = MediaQuery.of(context)!.size.height;
+          screenHeight = MediaQuery.of(context).size.height;
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
             child: CupertinoActionSheet(
               title: const Text('The title'),
               message: Text('Very long content' * 200),

packages/flutter/test/cupertino/colors_test.dart

@@ -283,7 +283,7 @@ void main() {
 
       // Asserts when the required dependency is missing.
       await tester.pumpWidget(const DependentWidget(color: contrastDependentColor1));
-      expect(tester.takeException()?.toString(), contains('does not contain a MediaQuery'));
+      expect(tester.takeException()?.toString(), contains('No MediaQuery widget ancestor found'));
   });
 
   testWidgets(

packages/flutter/test/cupertino/date_picker_test.dart

@@ -1386,7 +1386,7 @@ void main() {
         home: StatefulBuilder(builder: (BuildContext context, StateSetter stateSetter) {
           setState = stateSetter;
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(platformBrightness: brightness),
+            data: MediaQuery.of(context).copyWith(platformBrightness: brightness),
             child: CupertinoDatePicker(
               initialDateTime: DateTime(2019),
               mode: CupertinoDatePickerMode.date,

packages/flutter/test/cupertino/dialog_test.dart

@@ -275,7 +275,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
             child: CupertinoAlertDialog(
               title: const Text('The Title'),
               content: Text('Very long content ' * 20),
@@ -375,7 +375,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
             child: CupertinoAlertDialog(
               title: const Text('The title'),
               content: const Text('The content.'),
@@ -436,7 +436,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
             child: CupertinoAlertDialog(
               actions: const <Widget>[
                 CupertinoDialogAction(
@@ -487,7 +487,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
             child: CupertinoAlertDialog(
               title: const Text('The title'),
               content: const Text('The content.'),
@@ -556,7 +556,7 @@ void main() {
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
-          dividerWidth = 1.0 / MediaQuery.of(context)!.devicePixelRatio;
+          dividerWidth = 1.0 / MediaQuery.of(context).devicePixelRatio;
           return CupertinoAlertDialog(
             title: const Text('The Title'),
             content: const Text('The message'),
@@ -601,7 +601,7 @@ void main() {
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
-          dividerThickness = 1.0 / MediaQuery.of(context)!.devicePixelRatio;
+          dividerThickness = 1.0 / MediaQuery.of(context).devicePixelRatio;
           return CupertinoAlertDialog(
             title: const Text('The Title'),
             content: const Text('The message'),
@@ -677,7 +677,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
             child: CupertinoAlertDialog(
               title: const Text('The Title'),
               content: Text('The message\n' * 20),
@@ -809,7 +809,7 @@ void main() {
     await tester.pumpWidget(
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
-          dividerThickness = 1.0 / MediaQuery.of(context)!.devicePixelRatio;
+          dividerThickness = 1.0 / MediaQuery.of(context).devicePixelRatio;
           return CupertinoAlertDialog(
             title: const Text('The Title'),
             content: const Text('The message'),
@@ -1151,7 +1151,7 @@ void main() {
       createAppWithButtonThatLaunchesDialog(
         dialogBuilder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
             child: const RepaintBoundary(
               child: CupertinoAlertDialog(
                 title: Text('Title'),

packages/flutter/test/cupertino/material/tab_scaffold_test.dart

@@ -282,7 +282,7 @@ void main() {
       MaterialApp(
         home: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 99),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 99),
             child: CupertinoTabScaffold(
               tabBar: CupertinoTabBar(
                 items: List<BottomNavigationBarItem>.generate(

packages/flutter/test/cupertino/nav_bar_test.dart

@@ -1106,7 +1106,7 @@ void main() {
       CupertinoApp(
         home: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 99),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 99),
             child: CupertinoPageScaffold(
               child: CustomScrollView(
                 slivers: <Widget>[
@@ -1154,7 +1154,7 @@ void main() {
       title: 'title',
       builder: (BuildContext context) {
         return MediaQuery(
-          data: MediaQuery.of(context)!.copyWith(textScaleFactor: 99),
+          data: MediaQuery.of(context).copyWith(textScaleFactor: 99),
           child: Container(
             child: const CupertinoPageScaffold(
               child: CustomScrollView(

packages/flutter/test/cupertino/scaffold_test.dart

@@ -49,7 +49,7 @@ void main() {
       ),
     ));
 
-    expect(MediaQuery.of(childContext)!.padding.top, 0);
+    expect(MediaQuery.of(childContext).padding.top, 0);
     // The top of the [Container] is 44 px from the top of the screen because
     // it's pushed down by the opaque navigation bar whose height is 44 px,
     // and the 20 px [MediaQuery] top padding is fully absorbed by the navigation bar.
@@ -94,12 +94,12 @@ void main() {
     }
     await tester.pumpWidget(scaffoldWithBrightness(Brightness.light));
 
-    expect(MediaQuery.of(childContext)!.padding.top, 0);
+    expect(MediaQuery.of(childContext).padding.top, 0);
     expect(find.byType(CupertinoPageScaffold), paints..rect(color: backgroundColor.color));
 
     await tester.pumpWidget(scaffoldWithBrightness(Brightness.dark));
 
-    expect(MediaQuery.of(childContext)!.padding.top, greaterThan(0));
+    expect(MediaQuery.of(childContext).padding.top, greaterThan(0));
     expect(find.byType(CupertinoPageScaffold), paints..rect(color: backgroundColor.darkColor));
   });
 
@@ -142,7 +142,7 @@ void main() {
     expect(tester.getSize(find.byType(Container)).height, 600.0 - 100.0);
     // The shouldn't see a media query view inset because it was consumed by
     // the scaffold.
-    expect(MediaQuery.of(childContext)!.viewInsets.bottom, 0);
+    expect(MediaQuery.of(childContext).viewInsets.bottom, 0);
 
     await tester.pumpWidget(Directionality(
       textDirection: TextDirection.ltr,
@@ -439,7 +439,7 @@ void main() {
         builder: (BuildContext context, Widget? child) {
           // Acts as a 20px status bar at the root of the app.
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(padding: const EdgeInsets.only(top: 20)),
+            data: MediaQuery.of(context).copyWith(padding: const EdgeInsets.only(top: 20)),
             child: child!,
           );
         },
@@ -537,7 +537,7 @@ void main() {
       CupertinoApp(
         home: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 99),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 99),
             child: const CupertinoPageScaffold(
               navigationBar: CupertinoNavigationBar(
                 middle: Text('middle'),

packages/flutter/test/cupertino/tab_scaffold_test.dart

@@ -406,7 +406,7 @@ void main() {
     expect(tester.getRect(find.byType(Placeholder)), const Rect.fromLTWH(0, 0, 800, 400));
     // Don't generate more media query padding from the translucent bottom
     // tab since the tab is behind the keyboard now.
-    expect(MediaQuery.of(innerContext)!.padding.bottom, 0);
+    expect(MediaQuery.of(innerContext).padding.bottom, 0);
   });
 
   testWidgets('Tab contents are not inset when resizeToAvoidBottomInset overridden', (WidgetTester tester) async {
@@ -433,7 +433,7 @@ void main() {
     expect(tester.getRect(find.byType(Placeholder)), const Rect.fromLTWH(0, 0, 800, 600));
     // Media query padding shows up in the inner content because it wasn't masked
     // by the view inset.
-    expect(MediaQuery.of(innerContext)!.padding.bottom, 50);
+    expect(MediaQuery.of(innerContext).padding.bottom, 50);
   });
 
   testWidgets('Tab contents bottom padding are not consumed by viewInsets when resizeToAvoidBottomInset overridden', (WidgetTester tester) async {
@@ -502,7 +502,7 @@ void main() {
                   items: List<BottomNavigationBarItem>.generate(2, tabGenerator),
                 ),
                 tabBuilder: (BuildContext context, int index) {
-                  contentPadding = MediaQuery.of(context)!.padding;
+                  contentPadding = MediaQuery.of(context).padding;
                   return const Placeholder();
                 }
               ),
@@ -543,7 +543,7 @@ void main() {
     );
 
     expect(tester.getRect(find.byType(Placeholder)), const Rect.fromLTWH(0, 0, 800, 400));
-    expect(MediaQuery.of(innerContext)!.padding.bottom, 0);
+    expect(MediaQuery.of(innerContext).padding.bottom, 0);
   });
 
   testWidgets('Deleting tabs after selecting them should switch to the last available tab', (WidgetTester tester) async {
@@ -1074,7 +1074,7 @@ void main() {
       CupertinoApp(
         home: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: 99),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 99),
             child: CupertinoTabScaffold(
               tabBar: CupertinoTabBar(
                 items: List<BottomNavigationBarItem>.generate(

packages/flutter/test/material/app_bar_test.dart

@@ -1957,7 +1957,7 @@ void main() {
         home: Builder(
           builder: (BuildContext context) {
             return MediaQuery(
-              data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
+              data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
               child: Scaffold(
                 appBar: AppBar(
                   centerTitle: false,
@@ -2002,7 +2002,7 @@ void main() {
                     appBar: AppBar(
                       centerTitle: centerTitle,
                       title: MediaQuery(
-                        data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
+                        data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
                         child: const Text('Jumbo'),
                       ),
                     ),

packages/flutter/test/material/app_test.dart

@@ -464,7 +464,7 @@ void main() {
     double? textScaleFactor;
     await tester.pumpWidget(MaterialApp(
       home: Builder(builder:(BuildContext context) {
-        textScaleFactor = MediaQuery.of(context)!.textScaleFactor;
+        textScaleFactor = MediaQuery.of(context).textScaleFactor;
         return Container();
       }),
     ));

packages/flutter/test/material/bottom_sheet_test.dart

@@ -467,11 +467,11 @@ void main() {
     await tester.pump(const Duration(seconds: 1));
 
     expect(
-      MediaQuery.of(outerContext)!.padding,
+      MediaQuery.of(outerContext).padding,
       const EdgeInsets.all(50.0),
     );
     expect(
-      MediaQuery.of(innerContext)!.padding,
+      MediaQuery.of(innerContext).padding,
       const EdgeInsets.only(left: 50.0, right: 50.0, bottom: 50.0),
     );
   });

packages/flutter/test/material/circle_avatar_test.dart

@@ -169,7 +169,7 @@ void main() {
           child: CircleAvatar(
             child: Builder(
               builder: (BuildContext context) {
-                final MediaQueryData data = MediaQuery.of(context)!;
+                final MediaQueryData data = MediaQuery.of(context);
 
                 // These should not change.
                 expect(data.size, equals(const Size(111.0, 111.0)));

packages/flutter/test/material/dialog_test.dart

@@ -25,7 +25,7 @@ MaterialApp _buildAppWithDialog(Widget dialog, { ThemeData? theme, double textSc
                   context: context,
                   builder: (BuildContext context) {
                     return MediaQuery(
-                      data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
+                      data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
                       child: dialog,
                     );
                   },
@@ -1188,12 +1188,12 @@ void main() {
 
     await tester.pump();
 
-    expect(MediaQuery.of(outerContext)!.padding, const EdgeInsets.all(50.0));
+    expect(MediaQuery.of(outerContext).padding, const EdgeInsets.all(50.0));
-    expect(MediaQuery.of(routeContext)!.padding, EdgeInsets.zero);
+    expect(MediaQuery.of(routeContext).padding, EdgeInsets.zero);
-    expect(MediaQuery.of(dialogContext)!.padding, EdgeInsets.zero);
+    expect(MediaQuery.of(dialogContext).padding, EdgeInsets.zero);
-    expect(MediaQuery.of(outerContext)!.viewInsets, const EdgeInsets.only(left: 25.0, bottom: 75.0));
+    expect(MediaQuery.of(outerContext).viewInsets, const EdgeInsets.only(left: 25.0, bottom: 75.0));
-    expect(MediaQuery.of(routeContext)!.viewInsets, const EdgeInsets.only(left: 25.0, bottom: 75.0));
+    expect(MediaQuery.of(routeContext).viewInsets, const EdgeInsets.only(left: 25.0, bottom: 75.0));
-    expect(MediaQuery.of(dialogContext)!.viewInsets, EdgeInsets.zero);
+    expect(MediaQuery.of(dialogContext).viewInsets, EdgeInsets.zero);
   });
 
   testWidgets('Dialog widget insets by viewInsets', (WidgetTester tester) async {

packages/flutter/test/material/dropdown_test.dart

@@ -2086,7 +2086,7 @@ void main() {
         builder: (BuildContext context, StateSetter setState) {
           return MaterialApp(
             builder: (BuildContext context, Widget? child) {
-              mediaQuery = MediaQuery.of(context)!;
+              mediaQuery = MediaQuery.of(context);
               return MediaQuery(
                 data: mediaQuery,
                 child: child!,

packages/flutter/test/material/elevated_button_test.dart

@@ -766,7 +766,7 @@ void main() {
                 home: Builder(
                   builder: (BuildContext context) {
                     return MediaQuery(
-                      data: MediaQuery.of(context)!.copyWith(
+                      data: MediaQuery.of(context).copyWith(
                         textScaleFactor: textScaleFactor,
                       ),
                       child: Directionality(
@@ -902,7 +902,7 @@ void main() {
         home: Builder(
           builder: (BuildContext context) {
             return MediaQuery(
-              data: MediaQuery.of(context)!.copyWith(
+              data: MediaQuery.of(context).copyWith(
                 textScaleFactor: 2,
               ),
               child: Scaffold(

packages/flutter/test/material/flexible_space_bar_test.dart

@@ -394,7 +394,7 @@ void main() {
         home: Scaffold(
           body: Builder(
             builder: (BuildContext context) {
-              width = MediaQuery.of(context)!.size.width;
+              width = MediaQuery.of(context).size.width;
               return CustomScrollView(
                 slivers: <Widget>[
                   SliverAppBar(

packages/flutter/test/material/navigation_rail_test.dart

@@ -1706,7 +1706,7 @@ void main() {
               body: Row(
                 children: <Widget>[
                   MediaQuery(
-                    data: MediaQuery.of(context)!.copyWith(textScaleFactor: 3.0),
+                    data: MediaQuery.of(context).copyWith(textScaleFactor: 3.0),
                     child: NavigationRail(
                       selectedIndex: 0,
                       destinations: const <NavigationRailDestination>[
@@ -2111,7 +2111,7 @@ Future<void> _pumpNavigationRail(
       home: Builder(
         builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(textScaleFactor: textScaleFactor),
+            data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
             child: Scaffold(
               body: Row(
                 children: <Widget>[

packages/flutter/test/material/outlined_button_test.dart

@@ -1009,7 +1009,7 @@ void main() {
                 home: Builder(
                   builder: (BuildContext context) {
                     return MediaQuery(
-                      data: MediaQuery.of(context)!.copyWith(
+                      data: MediaQuery.of(context).copyWith(
                         textScaleFactor: textScaleFactor,
                       ),
                       child: Directionality(
@@ -1148,7 +1148,7 @@ void main() {
         home: Builder(
           builder: (BuildContext context) {
             return MediaQuery(
-              data: MediaQuery.of(context)!.copyWith(
+              data: MediaQuery.of(context).copyWith(
                 textScaleFactor: 2,
               ),
               child: Scaffold(

packages/flutter/test/material/persistent_bottom_sheet_test.dart

@@ -408,7 +408,7 @@ void main() {
     await tester.pump();
 
     expect(
-      MediaQuery.of(bottomSheetContext)!.padding,
+      MediaQuery.of(bottomSheetContext).padding,
       const EdgeInsets.only(
         bottom: 50.0,
         left: 50.0,

packages/flutter/test/material/popup_menu_test.dart

@@ -138,7 +138,7 @@ void main() {
       return MaterialApp(
         home: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(
+            data: MediaQuery.of(context).copyWith(
               navigationMode: NavigationMode.directional,
             ),
             child: Material(
@@ -254,7 +254,7 @@ void main() {
       MaterialApp(
         home: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(
+            data: MediaQuery.of(context).copyWith(
               navigationMode: NavigationMode.directional,
             ),
             child: Material(
@@ -755,7 +755,7 @@ void main() {
 
     await tester.pump();
 
-    expect(MediaQuery.of(popupContext)!.padding, EdgeInsets.zero);
+    expect(MediaQuery.of(popupContext).padding, EdgeInsets.zero);
   });
 
   testWidgets('Popup Menu Offset Test', (WidgetTester tester) async {

packages/flutter/test/material/scaffold_test.dart

@@ -683,7 +683,7 @@ void main() {
               extendBody: extendBody,
               body: Builder(
                 builder: (BuildContext context) {
-                  mediaQueryBottom = MediaQuery.of(context)!.padding.bottom;
+                  mediaQueryBottom = MediaQuery.of(context).padding.bottom;
                   return Container(key: bodyKey);
                 },
               ),
@@ -756,7 +756,7 @@ void main() {
                   ),
                   body: Builder(
                     builder: (BuildContext context) {
-                      mediaQueryTop = MediaQuery.of(context)!.padding.top;
+                      mediaQueryTop = MediaQuery.of(context).padding.top;
                       return Container(key: bodyKey);
                     }
                   ),
@@ -1675,7 +1675,7 @@ void main() {
       MaterialApp(
         home: Builder(
           builder: (BuildContext context) {
-            screenWidth = MediaQuery.of(context)!.size.width;
+            screenWidth = MediaQuery.of(context).size.width;
             return Scaffold(
               endDrawer: const Drawer(
                 child: Text('Drawer'),

packages/flutter/test/material/text_button_test.dart

@@ -804,7 +804,7 @@ void main() {
                 home: Builder(
                   builder: (BuildContext context) {
                     return MediaQuery(
-                      data: MediaQuery.of(context)!.copyWith(
+                      data: MediaQuery.of(context).copyWith(
                         textScaleFactor: textScaleFactor,
                       ),
                       child: Directionality(
@@ -946,7 +946,7 @@ void main() {
         home: Builder(
           builder: (BuildContext context) {
             return MediaQuery(
-              data: MediaQuery.of(context)!.copyWith(
+              data: MediaQuery.of(context).copyWith(
                 textScaleFactor: 2,
               ),
               child: Scaffold(

packages/flutter/test/material/text_field_test.dart

@@ -5439,7 +5439,7 @@ void main() {
       boilerplate(
         child: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(
+            data: MediaQuery.of(context).copyWith(
               navigationMode: NavigationMode.directional,
             ),
             child: TextField(
@@ -5460,7 +5460,7 @@ void main() {
       boilerplate(
         child: Builder(builder: (BuildContext context) {
           return MediaQuery(
-            data: MediaQuery.of(context)!.copyWith(
+            data: MediaQuery.of(context).copyWith(
               navigationMode: NavigationMode.directional,
             ),
             child:  TextField(

packages/flutter/test/widgets/debug_test.dart

@@ -111,23 +111,29 @@ void main() {
             expect(
               error.diagnostics.last.toStringDeep(),
               equalsIgnoringHashCodes(
-                'Typically, the MediaQuery widget is introduced by the MaterialApp\n'
+                'No MediaQuery ancestor could be found starting from the context\n'
-                'or WidgetsApp widget at the top of your application widget tree.\n'
+                'that was passed to MediaQuery.of(). This can happen because you\n'
+                'have not added a WidgetsApp, CupertinoApp, or MaterialApp widget\n'
+                '(those widgets introduce a MediaQuery), or it can happen if the\n'
+                'context you use comes from a widget above those widgets.\n'
               ),
             );
             expect(
               error.toStringDeep(),
               equalsIgnoringHashCodes(
                 'FlutterError\n'
-                '   No MediaQuery widget found.\n'
+                '   No MediaQuery widget ancestor found.\n'
                 '   Builder widgets require a MediaQuery widget ancestor.\n'
                 '   The specific widget that could not find a MediaQuery ancestor\n'
                 '   was:\n'
                 '     Builder\n'
                 '   The ownership chain for the affected widget is: "Builder ←\n'
                 '     [root]"\n'
-                '   Typically, the MediaQuery widget is introduced by the MaterialApp\n'
+                '   No MediaQuery ancestor could be found starting from the context\n'
-                '   or WidgetsApp widget at the top of your application widget tree.\n'
+                '   that was passed to MediaQuery.of(). This can happen because you\n'
+                '   have not added a WidgetsApp, CupertinoApp, or MaterialApp widget\n'
+                '   (those widgets introduce a MediaQuery), or it can happen if the\n'
+                '   context you use comes from a widget above those widgets.\n'
               ),
             );
           }

packages/flutter/test/widgets/list_view_test.dart

@@ -382,7 +382,7 @@ void main() {
             children: <Widget>[
               const Text('top', textDirection: TextDirection.ltr),
               Builder(builder: (BuildContext context) {
-                innerMediaQueryPadding = MediaQuery.of(context)!.padding;
+                innerMediaQueryPadding = MediaQuery.of(context).padding;
                 return Container();
               }),
             ],

packages/flutter/test/widgets/media_query_test.dart

@@ -24,31 +24,54 @@ void main() {
     expect(exception, isNotNull);
     expect(exception ,isFlutterError);
     final FlutterError error = exception as FlutterError;
-    expect(error.diagnostics.length, 3);
+    expect(error.diagnostics.length, 5);
-    expect(error.diagnostics.last, isA<DiagnosticsProperty<Element>>());
+    expect(error.diagnostics.last, isA<ErrorHint>());
     expect(
       error.toStringDeep(),
       equalsIgnoringHashCodes(
         'FlutterError\n'
-        '   MediaQuery.of() called with a context that does not contain a\n'
+        '   No MediaQuery widget ancestor found.\n'
-        '   MediaQuery.\n'
+        '   Builder widgets require a MediaQuery widget ancestor.\n'
+        '   The specific widget that could not find a MediaQuery ancestor\n'
+        '   was:\n'
+        '     Builder\n'
+        '   The ownership chain for the affected widget is: "Builder ←\n'
+        '     [root]"\n'
         '   No MediaQuery ancestor could be found starting from the context\n'
         '   that was passed to MediaQuery.of(). This can happen because you\n'
-        '   do not have a WidgetsApp or MaterialApp widget (those widgets\n'
+        '   have not added a WidgetsApp, CupertinoApp, or MaterialApp widget\n'
-        '   introduce a MediaQuery), or it can happen if the context you use\n'
+        '   (those widgets introduce a MediaQuery), or it can happen if the\n'
-        '   comes from a widget above those widgets.\n'
+        '   context you use comes from a widget above those widgets.\n'
-        '   The context used was:\n'
-        '     Builder\n',
       ),
     );
   });
 
-  testWidgets('MediaQuery defaults to null', (WidgetTester tester) async {
+  testWidgets('MediaQuery.of finds a MediaQueryData when there is one', (WidgetTester tester) async {
+    bool tested = false;
+    await tester.pumpWidget(
+      MediaQuery(
+        data: const MediaQueryData(),
+        child: Builder(
+          builder: (BuildContext context) {
+            final MediaQueryData data = MediaQuery.of(context);
+            expect(data, isNotNull);
+            tested = true;
+            return Container();
+          },
+        ),
+      ),
+    );
+    final dynamic exception = tester.takeException();
+    expect(exception, isNull);
+    expect(tested, isTrue);
+  });
+
+  testWidgets('MediaQuery.maybeOf defaults to null', (WidgetTester tester) async {
     bool tested = false;
     await tester.pumpWidget(
       Builder(
         builder: (BuildContext context) {
-          final MediaQueryData? data = MediaQuery.of(context, nullOk: true);
+          final MediaQueryData? data = MediaQuery.maybeOf(context);
           expect(data, isNull);
           tested = true;
           return Container();
@@ -58,7 +81,25 @@ void main() {
     expect(tested, isTrue);
   });
 
-  testWidgets('MediaQueryData is sane', (WidgetTester tester) async {
+  testWidgets('MediaQuery.maybeOf finds a MediaQueryData when there is one', (WidgetTester tester) async {
+    bool tested = false;
+    await tester.pumpWidget(
+      MediaQuery(
+        data: const MediaQueryData(),
+        child: Builder(
+          builder: (BuildContext context) {
+            final MediaQueryData? data = MediaQuery.maybeOf(context);
+            expect(data, isNotNull);
+            tested = true;
+            return Container();
+          },
+        ),
+      ),
+    );
+    expect(tested, isTrue);
+  });
+
+  testWidgets('MediaQueryData.fromWindow is sane', (WidgetTester tester) async {
     final MediaQueryData data = MediaQueryData.fromWindow(WidgetsBinding.instance!.window);
     expect(data, hasOneLineDescription);
     expect(data.hashCode, equals(data.copyWith().hashCode));
@@ -169,7 +210,7 @@ void main() {
               removeBottom: true,
               child: Builder(
                 builder: (BuildContext context) {
-                  unpadded = MediaQuery.of(context)!;
+                  unpadded = MediaQuery.of(context);
                   return Container();
                 },
               ),
@@ -225,7 +266,7 @@ void main() {
               context: context,
               child: Builder(
                 builder: (BuildContext context) {
-                  unpadded = MediaQuery.of(context)!;
+                  unpadded = MediaQuery.of(context);
                   return Container();
                 },
               ),
@@ -284,7 +325,7 @@ void main() {
               removeBottom: true,
               child: Builder(
                 builder: (BuildContext context) {
-                  unpadded = MediaQuery.of(context)!;
+                  unpadded = MediaQuery.of(context);
                   return Container();
                 },
               ),
@@ -340,7 +381,7 @@ void main() {
               removeBottom: true,
               child: Builder(
                 builder: (BuildContext context) {
-                  unpadded = MediaQuery.of(context)!;
+                  unpadded = MediaQuery.of(context);
                   return Container();
                 },
               ),
@@ -399,7 +440,7 @@ void main() {
               removeBottom: true,
               child: Builder(
                 builder: (BuildContext context) {
-                  unpadded = MediaQuery.of(context)!;
+                  unpadded = MediaQuery.of(context);
                   return Container();
                 },
               ),
@@ -455,7 +496,7 @@ void main() {
               removeLeft: true,
               child: Builder(
                 builder: (BuildContext context) {
-                  unpadded = MediaQuery.of(context)!;
+                  unpadded = MediaQuery.of(context);
                   return Container();
                 },
               ),

packages/flutter/test/widgets/render_object_widget_test.dart

@@ -28,7 +28,7 @@ class TestOrientedBox extends SingleChildRenderObjectWidget {
   const TestOrientedBox({ Key? key, Widget? child }) : super(key: key, child: child);
 
   Decoration _getDecoration(BuildContext context) {
-    final Orientation orientation = MediaQuery.of(context)!.orientation;
+    final Orientation orientation = MediaQuery.of(context).orientation;
     switch (orientation) {
       case Orientation.landscape:
         return const BoxDecoration(color: Color(0xFF00FF00));

packages/flutter/test/widgets/selectable_text_test.dart

@@ -2276,7 +2276,7 @@ void main() {
     await tester.pumpWidget(selectableText);
     final dynamic exception = tester.takeException();
     expect(exception, isFlutterError);
-    expect(exception.toString(), startsWith('No MediaQuery widget found.\nSelectableText widgets require a MediaQuery widget ancestor.'));
+    expect(exception.toString(), startsWith('No MediaQuery widget ancestor found.\nSelectableText widgets require a MediaQuery widget ancestor.'));
   });
 
   testWidgets('onTap is called upon tap', (WidgetTester tester) async {