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Better defaulting for scroll view primary-ness (#8506)

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* Improved defaults for scroll view primary-ness

* Vertical scroll views default to primary:true.
* Horizontal scroll views default to primary:false.
* If a scroll view is primary and it got a non-null inherited primary
  scroll controller, it introduces a primary scroll controller inherited
  with a value of null for its descendants.

ScrollController now multiplexes writes to all registered positions;
reads of position continue to assert that only one position is
registered. Reads still require a single position.
This commit is contained in:
Chris Bracken 2017-03-01 16:13:09 -08:00 committed by GitHub
parent a76c352d57
commit 5271546794
7 changed files with 206 additions and 30 deletions
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8
packages/flutter/lib/src/widgets/primary_scroll_controller.dart
View File

@ -16,6 +16,12 @@ class PrimaryScrollController extends InheritedWidget {
assert(controller != null);
}
const PrimaryScrollController.none({
Key key,
@required Widget child
}) : controller = null,
super(key: key, child: child);
final ScrollController controller;
static ScrollController of(BuildContext context) {
@ -29,6 +35,6 @@ class PrimaryScrollController extends InheritedWidget {
@override
void debugFillDescription(List<String> description) {
super.debugFillDescription(description);
description.add('$controller');
description.add('${controller ?? 'no controller'}');
}
}

14
packages/flutter/lib/src/widgets/scroll_controller.dart
View File

@ -68,7 +68,13 @@ class ScrollController {
Future<Null> animateTo(double offset, {
@required Duration duration,
@required Curve curve,
}) => position.animateTo(offset, duration: duration, curve: curve);
}) {
assert(_positions.isNotEmpty, 'ScrollController not attached to any scroll views.');
List<Future<Null>> animations = new List<Future<Null>>(_positions.length);
for (int i = 0; i < _positions.length; i++)
animations[i] = _positions[i].animateTo(offset, duration: duration, curve: curve);
return Future.wait<Null>(animations).then((List<Null> _) => null);
}
/// Jumps the scroll position from its current value to the given value,
/// without animation, and without checking if the new value is in range.
@ -82,7 +88,11 @@ class ScrollController {
///
/// Immediately after the jump, a ballistic activity is started, in case the
/// value was out of range.
void jumpTo(double value) => position.jumpTo(value);
void jumpTo(double value) {
assert(_positions.isNotEmpty, 'ScrollController not attached to any scroll views.');
for (ScrollPosition p in _positions)
p.jumpTo(value);
}
/// Register the given position with this controller.
///

50
packages/flutter/lib/src/widgets/scroll_view.dart
View File

@ -21,14 +21,15 @@ abstract class ScrollView extends StatelessWidget {
this.scrollDirection: Axis.vertical,
this.reverse: false,
this.controller,
this.primary: false,
bool primary,
this.physics,
this.shrinkWrap: false,
}) : super(key: key) {
assert(reverse != null);
assert(shrinkWrap != null);
assert(primary != null);
assert(controller == null || !primary,
}) : primary = primary ?? controller == null && scrollDirection == Axis.vertical,
super(key: key) {
assert(this.reverse != null);
assert(this.shrinkWrap != null);
assert(this.primary != null);
assert(this.controller == null || !this.primary,
'Primary ScrollViews obtain their ScrollController via inheritance from a PrimaryScrollController widget. '
'You cannot both set primary to true and pass an explicit controller.'
);
@ -40,6 +41,14 @@ abstract class ScrollView extends StatelessWidget {
final ScrollController controller;
/// Whether this is the primary scroll view associated with the parent
/// [PrimaryScrollController].
///
/// On iOS, this identifies the scroll view that will scroll to top in
/// response to a tap in the status bar.
///
/// Defaults to true when `scrollDirection` is vertical and `controller` is
/// not specified.
final bool primary;
final ScrollPhysics physics;
@ -65,9 +74,13 @@ abstract class ScrollView extends StatelessWidget {
Widget build(BuildContext context) {
List<Widget> slivers = buildSlivers(context);
AxisDirection axisDirection = getDirection(context);
return new Scrollable(
ScrollController scrollController = primary
? PrimaryScrollController.of(context)
: controller;
Scrollable scrollable = new Scrollable(
axisDirection: axisDirection,
controller: controller ?? (primary ? PrimaryScrollController.of(context) : null),
controller: scrollController,
physics: physics,
viewportBuilder: (BuildContext context, ViewportOffset offset) {
if (shrinkWrap) {
@ -85,6 +98,9 @@ abstract class ScrollView extends StatelessWidget {
}
}
);
return primary && scrollController != null
? new PrimaryScrollController.none(child: scrollable)
: scrollable;
}
@override
@ -110,7 +126,7 @@ class CustomScrollView extends ScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
this.slivers: const <Widget>[],
@ -136,7 +152,7 @@ abstract class BoxScrollView extends ScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
this.padding,
@ -185,7 +201,7 @@ class ListView extends BoxScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
EdgeInsets padding,
@ -207,7 +223,7 @@ class ListView extends BoxScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
EdgeInsets padding,
@ -230,7 +246,7 @@ class ListView extends BoxScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
EdgeInsets padding,
@ -286,7 +302,7 @@ class GridView extends BoxScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
EdgeInsets padding,
@ -310,7 +326,7 @@ class GridView extends BoxScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
EdgeInsets padding,
@ -335,7 +351,7 @@ class GridView extends BoxScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
EdgeInsets padding,
@ -366,7 +382,7 @@ class GridView extends BoxScrollView {
Axis scrollDirection: Axis.vertical,
bool reverse: false,
ScrollController controller,
bool primary: false,
bool primary,
ScrollPhysics physics,
bool shrinkWrap: false,
EdgeInsets padding,

29
packages/flutter/lib/src/widgets/single_child_scroll_view.dart
View File

@ -43,14 +43,15 @@ class SingleChildScrollView extends StatelessWidget {
this.scrollDirection: Axis.vertical,
this.reverse: false,
this.padding,
this.primary: false,
bool primary,
this.physics,
this.controller,
this.child,
}) : super(key: key) {
assert(scrollDirection != null);
assert(primary != null);
assert(controller == null || !primary,
}) : primary = primary ?? controller == null && scrollDirection == Axis.vertical,
super(key: key) {
assert(this.scrollDirection != null);
assert(this.primary != null);
assert(this.controller == null || !this.primary,
'Primary ScrollViews obtain their ScrollController via inheritance from a PrimaryScrollController widget. '
'You cannot both set primary to true and pass an explicit controller.'
);
@ -64,6 +65,14 @@ class SingleChildScrollView extends StatelessWidget {
final ScrollController controller;
/// Whether this is the primary scroll view associated with the parent
/// [PrimaryScrollController].
///
/// On iOS, this identifies the scroll view that will scroll to top in
/// response to a tap in the status bar.
///
/// Defaults to true when `scrollDirection` is vertical and `controller` is
/// not specified.
final bool primary;
final ScrollPhysics physics;
@ -87,9 +96,12 @@ class SingleChildScrollView extends StatelessWidget {
Widget contents = child;
if (padding != null)
contents = new Padding(padding: padding, child: contents);
return new Scrollable(
ScrollController scrollController = primary
? PrimaryScrollController.of(context)
: controller;
Scrollable scrollable = new Scrollable(
axisDirection: axisDirection,
controller: controller ?? (primary ? PrimaryScrollController.of(context) : null),
controller: scrollController,
physics: physics,
viewportBuilder: (BuildContext context, ViewportOffset offset) {
return new _SingleChildViewport(
@ -99,6 +111,9 @@ class SingleChildScrollView extends StatelessWidget {
);
},
);
return primary && scrollController != null
? new PrimaryScrollController.none(child: scrollable)
: scrollable;
}
}

8
packages/flutter/test/widgets/scroll_controller_test.dart
View File

@ -201,7 +201,7 @@ void main() {
expect(() => controller.jumpTo(1.0), throwsAssertionError);
});
testWidgets('Write operations on ScrollControllers with more than one position fail', (WidgetTester tester) async {
testWidgets('Write operations on ScrollControllers with more than one position do not throw', (WidgetTester tester) async {
ScrollController controller = new ScrollController();
await tester.pumpWidget(new ListView(
children: <Widget>[
@ -226,7 +226,9 @@ void main() {
],
));
expect(() => controller.jumpTo(1.0), throwsAssertionError);
expect(() => controller.animateTo(1.0, duration: const Duration(seconds: 1), curve: Curves.linear), throwsAssertionError);
controller.jumpTo(1.0);
controller.animateTo(1.0, duration: const Duration(seconds: 1), curve: Curves.linear);
await tester.pump();
await tester.pumpUntilNoTransientCallbacks();
});
}

86
packages/flutter/test/widgets/scroll_view_test.dart
View File

@ -169,6 +169,67 @@ void main() {
expect(log, isEmpty);
});
testWidgets('Vertical CustomScrollViews are primary by default', (WidgetTester tester) async {
CustomScrollView view = new CustomScrollView(scrollDirection: Axis.vertical);
expect(view.primary, isTrue);
});
testWidgets('Vertical ListViews are primary by default', (WidgetTester tester) async {
ListView view = new ListView(scrollDirection: Axis.vertical);
expect(view.primary, isTrue);
});
testWidgets('Vertical GridViews are primary by default', (WidgetTester tester) async {
GridView view = new GridView.count(
scrollDirection: Axis.vertical,
crossAxisCount: 1,
);
expect(view.primary, isTrue);
});
testWidgets('Horizontal CustomScrollViews are non-primary by default', (WidgetTester tester) async {
CustomScrollView view = new CustomScrollView(scrollDirection: Axis.horizontal);
expect(view.primary, isFalse);
});
testWidgets('Horizontal ListViews are non-primary by default', (WidgetTester tester) async {
ListView view = new ListView(scrollDirection: Axis.horizontal);
expect(view.primary, isFalse);
});
testWidgets('Horizontal GridViews are non-primary by default', (WidgetTester tester) async {
GridView view = new GridView.count(
scrollDirection: Axis.horizontal,
crossAxisCount: 1,
);
expect(view.primary, isFalse);
});
testWidgets('CustomScrollViews with controllers are non-primary by default', (WidgetTester tester) async {
CustomScrollView view = new CustomScrollView(
controller: new ScrollController(),
scrollDirection: Axis.vertical,
);
expect(view.primary, isFalse);
});
testWidgets('ListViews with controllers are non-primary by default', (WidgetTester tester) async {
ListView view = new ListView(
controller: new ScrollController(),
scrollDirection: Axis.vertical,
);
expect(view.primary, isFalse);
});
testWidgets('GridViews with controllers are non-primary by default', (WidgetTester tester) async {
GridView view = new GridView.count(
controller: new ScrollController(),
scrollDirection: Axis.vertical,
crossAxisCount: 1,
);
expect(view.primary, isFalse);
});
testWidgets('CustomScrollView sets PrimaryScrollController when primary', (WidgetTester tester) async {
ScrollController primaryScrollController = new ScrollController();
await tester.pumpWidget(new PrimaryScrollController(
@ -198,4 +259,29 @@ void main() {
Scrollable scrollable = tester.widget(find.byType(Scrollable));
expect(scrollable.controller, primaryScrollController);
});
testWidgets('Nested scrollables have a null PrimaryScrollController', (WidgetTester tester) async {
const Key innerKey = const Key('inner');
ScrollController primaryScrollController = new ScrollController();
await tester.pumpWidget(new PrimaryScrollController(
controller: primaryScrollController,
child: new ListView(
primary: true,
children: <Widget>[
new Container(
constraints: new BoxConstraints(maxHeight: 200.0),
child: new ListView(key: innerKey, primary: true),
),
],
),
));
Scrollable innerScrollable = tester.widget(
find.descendant(
of: find.byKey(innerKey),
matching: find.byType(Scrollable),
),
);
expect(innerScrollable.controller, isNull);
});
}

41
packages/flutter/test/widgets/single_child_scroll_view_test.dart
View File

@ -136,4 +136,45 @@ void main() {
),
));
});
testWidgets('Vertical SingleChildScrollViews are primary by default', (WidgetTester tester) async {
SingleChildScrollView view = new SingleChildScrollView(scrollDirection: Axis.vertical);
expect(view.primary, isTrue);
});
testWidgets('Horizontal SingleChildScrollViews are non-primary by default', (WidgetTester tester) async {
SingleChildScrollView view = new SingleChildScrollView(scrollDirection: Axis.horizontal);
expect(view.primary, isFalse);
});
testWidgets('SingleChildScrollViews with controllers are non-primary by default', (WidgetTester tester) async {
SingleChildScrollView view = new SingleChildScrollView(
controller: new ScrollController(),
scrollDirection: Axis.vertical,
);
expect(view.primary, isFalse);
});
testWidgets('Nested scrollables have a null PrimaryScrollController', (WidgetTester tester) async {
const Key innerKey = const Key('inner');
ScrollController primaryScrollController = new ScrollController();
await tester.pumpWidget(new PrimaryScrollController(
controller: primaryScrollController,
child: new SingleChildScrollView(
primary: true,
child: new Container(
constraints: new BoxConstraints(maxHeight: 200.0),
child: new ListView(key: innerKey, primary: true),
),
),
));
Scrollable innerScrollable = tester.widget(
find.descendant(
of: find.byKey(innerKey),
matching: find.byType(Scrollable),
),
);
expect(innerScrollable.controller, isNull);
});
}