Add enableInteractiveSelection to CupertinoTextField and test it (#32823)

Adds a field that already exists in Material's TextField.

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

@@ -186,6 +186,7 @@ class CupertinoTextField extends StatefulWidget {
     this.keyboardAppearance,
     this.scrollPadding = const EdgeInsets.all(20.0),
     this.dragStartBehavior = DragStartBehavior.start,
+    this.enableInteractiveSelection,
     this.scrollPhysics,
   }) : assert(textAlign != null),
        assert(autofocus != null),
@@ -423,12 +424,20 @@ class CupertinoTextField extends StatefulWidget {
   /// {@macro flutter.widgets.editableText.scrollPadding}
   final EdgeInsets scrollPadding;
 
+  /// {@macro flutter.widgets.editableText.enableInteractiveSelection}
+  final bool enableInteractiveSelection;
+
   /// {@macro flutter.widgets.scrollable.dragStartBehavior}
   final DragStartBehavior dragStartBehavior;
 
   /// {@macro flutter.widgets.edtiableText.scrollPhysics}
   final ScrollPhysics scrollPhysics;
 
+  /// {@macro flutter.rendering.editable.selectionEnabled}
+  bool get selectionEnabled {
+    return enableInteractiveSelection ?? !obscureText;
+  }
+
   @override
   _CupertinoTextFieldState createState() => _CupertinoTextFieldState();
 
@@ -456,6 +465,7 @@ class CupertinoTextField extends StatefulWidget {
     properties.add(IntProperty('maxLength', maxLength, defaultValue: null));
     properties.add(FlagProperty('maxLengthEnforced', value: maxLengthEnforced, ifTrue: 'max length enforced'));
     properties.add(DiagnosticsProperty<Color>('cursorColor', cursorColor, defaultValue: null));
+    properties.add(FlagProperty('selectionEnabled', value: selectionEnabled, defaultValue: true, ifFalse: 'selection disabled'));
     properties.add(DiagnosticsProperty<ScrollPhysics>('scrollPhysics', scrollPhysics, defaultValue: null));
   }
 }
@@ -530,11 +540,13 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with AutomaticK
   }
 
   void _handleForcePressStarted(ForcePressDetails details) {
+    if (widget.selectionEnabled) {
       _renderEditable.selectWordsInRange(
         from: details.globalPosition,
         cause: SelectionChangedCause.forcePress,
       );
     }
+  }
 
   void _handleForcePressEnded(ForcePressDetails details) {
     _renderEditable.selectWordsInRange(
@@ -546,23 +558,29 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with AutomaticK
   }
 
   void _handleSingleTapUp(TapUpDetails details) {
+    if (widget.selectionEnabled) {
       _renderEditable.selectWordEdge(cause: SelectionChangedCause.tap);
+    }
     _requestKeyboard();
   }
 
   void _handleSingleLongTapStart(LongPressStartDetails details) {
+    if (widget.selectionEnabled) {
       _renderEditable.selectPositionAt(
         from: details.globalPosition,
         cause: SelectionChangedCause.longPress,
       );
     }
+  }
 
   void _handleSingleLongTapMoveUpdate(LongPressMoveUpdateDetails details) {
+    if (widget.selectionEnabled) {
       _renderEditable.selectPositionAt(
         from: details.globalPosition,
         cause: SelectionChangedCause.longPress,
       );
     }
+  }
 
   void _handleSingleLongTapEnd(LongPressEndDetails details) {
     if (_shouldShowSelectionToolbar)
@@ -570,10 +588,12 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with AutomaticK
   }
 
   void _handleDoubleTapDown(TapDownDetails details) {
+    if (widget.selectionEnabled) {
       _renderEditable.selectWord(cause: SelectionChangedCause.tap);
       if (_shouldShowSelectionToolbar)
         _editableText.showToolbar();
     }
+  }
 
   bool _shouldShowSelectionHandles(SelectionChangedCause cause) {
     // When the text field is activated by something that doesn't trigger the
@@ -782,7 +802,8 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with AutomaticK
           minLines: widget.minLines,
           expands: widget.expands,
           selectionColor: _kSelectionHighlightColor,
-          selectionControls: cupertinoTextSelectionControls,
+          selectionControls: widget.selectionEnabled
+            ? cupertinoTextSelectionControls : null,
           onChanged: widget.onChanged,
           onSelectionChanged: _handleSelectionChanged,
           onEditingComplete: widget.onEditingComplete,
@@ -800,6 +821,7 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with AutomaticK
           keyboardAppearance: keyboardAppearance,
           dragStartBehavior: widget.dragStartBehavior,
           scrollPhysics: widget.scrollPhysics,
+          enableInteractiveSelection: widget.enableInteractiveSelection,
         ),
       ),
     );

packages/flutter/test/cupertino/text_field_test.dart

@@ -1399,6 +1399,102 @@ void main() {
     },
   );
 
+  testWidgets(
+    'An obscured CupertinoTextField is not selectable by default',
+    (WidgetTester tester) async {
+      final TextEditingController controller = TextEditingController(
+        text: 'Atwater Peel Sherbrooke Bonaventure',
+      );
+      await tester.pumpWidget(
+        CupertinoApp(
+          home: Center(
+            child: CupertinoTextField(
+              controller: controller,
+              obscureText: true,
+            ),
+          ),
+        ),
+      );
+
+      final Offset textfieldStart = tester.getTopLeft(find.byType(CupertinoTextField));
+
+      await tester.tapAt(textfieldStart + const Offset(150.0, 5.0));
+      await tester.pump(const Duration(milliseconds: 50));
+      final TestGesture gesture =
+         await tester.startGesture(textfieldStart + const Offset(150.0, 5.0));
+      // Hold the press.
+      await tester.pump(const Duration(milliseconds: 500));
+
+      // Nothing is selected despite the double tap long press gesture.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 35, extentOffset: 35),
+      );
+
+      // The selection menu is not present.
+      expect(find.byType(CupertinoButton), findsNWidgets(0));
+
+      await gesture.up();
+      await tester.pump();
+
+      // Still nothing selected and no selection menu.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 35, extentOffset: 35),
+      );
+      expect(find.byType(CupertinoButton), findsNWidgets(0));
+    },
+  );
+
+  testWidgets(
+    'An obscured CupertinoTextField is selectable when enabled',
+    (WidgetTester tester) async {
+      final TextEditingController controller = TextEditingController(
+        text: 'Atwater Peel Sherbrooke Bonaventure',
+      );
+      await tester.pumpWidget(
+        CupertinoApp(
+          home: Center(
+            child: CupertinoTextField(
+              controller: controller,
+              obscureText: true,
+              enableInteractiveSelection: true,
+            ),
+          ),
+        ),
+      );
+
+      final Offset textfieldStart = tester.getTopLeft(find.byType(CupertinoTextField));
+
+      await tester.tapAt(textfieldStart + const Offset(150.0, 5.0));
+      await tester.pump(const Duration(milliseconds: 50));
+      final TestGesture gesture =
+         await tester.startGesture(textfieldStart + const Offset(150.0, 5.0));
+      // Hold the press.
+      await tester.pump(const Duration(milliseconds: 500));
+
+      // The obscured text is not broken into words, so only one letter is
+      // selected at a time.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 9, extentOffset: 10),
+      );
+
+      // Selected text shows 3 toolbar buttons.
+      expect(find.byType(CupertinoButton), findsNWidgets(3));
+
+      await gesture.up();
+      await tester.pump();
+
+      // Still selected.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 9, extentOffset: 10),
+      );
+      expect(find.byType(CupertinoButton), findsNWidgets(3));
+    },
+  );
+
   testWidgets(
     'long press moves cursor to the exact long press position and shows toolbar',
     (WidgetTester tester) async {