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support nested scroll view #88

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support nested scroll view #88

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79 changes: 65 additions & 14 deletions example/lib/main.dart
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -37,27 +37,47 @@ class _MyHomePageState extends State<MyHomePage> {
static const double maxHeight = 1000;
final random = math.Random();
final scrollDirection = Axis.vertical;
final nestedParentScrollViewKey = GlobalKey();

late AutoScrollController controller;
late List<List<int>> randomList;
bool nested = false;

@override
void initState() {
super.initState();
controller = AutoScrollController(
viewportBoundaryGetter: () =>
Rect.fromLTRB(0, 0, 0, MediaQuery.of(context).padding.bottom),
axis: scrollDirection);
controller = _getController(nested);
randomList = List.generate(maxCount,
(index) => <int>[index, (maxHeight * random.nextDouble()).toInt()]);
}

AutoScrollController _getController(bool withScrollerKey) {
final scrollerKey = withScrollerKey ? nestedParentScrollViewKey : null;

return AutoScrollController(
viewportBoundaryGetter: () =>
Rect.fromLTRB(0, 0, 0, MediaQuery.of(context).padding.bottom),
axis: scrollDirection,
scrollerWidgetKey: scrollerKey, // only need to assign in nested use case
);
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
actions: [
IconButton(
onPressed: () {
setState(() {
nested = !nested;
controller = _getController(nested);
});
},
icon: Text(nested ? 'Single' : 'Nested'),
iconSize: 50,
),
IconButton(
onPressed: () {
setState(() => counter = 0);
Expand All @@ -74,16 +94,7 @@ class _MyHomePageState extends State<MyHomePage> {
)
],
),
body: ListView(
scrollDirection: scrollDirection,
controller: controller,
children: randomList.map<Widget>((data) {
return Padding(
padding: EdgeInsets.all(8),
child: _getRow(data[0], math.max(data[1].toDouble(), 50.0)),
);
}).toList(),
),
body: nested ? _buildNestedListView() : _buildSingleListView(),
floatingActionButton: FloatingActionButton(
onPressed: _nextCounter,
tooltip: 'Increment',
Expand All @@ -92,6 +103,46 @@ class _MyHomePageState extends State<MyHomePage> {
);
}

Widget _buildSingleListView() {
return ListView(
scrollDirection: scrollDirection,
controller: controller,
children: randomList.map<Widget>((data) {
return Padding(
padding: EdgeInsets.all(8),
child: _getRow(data[0], math.max(data[1].toDouble(), 50.0)),
);
}).toList(),
);
}

Widget _buildNestedListView() {
return SingleChildScrollView(
key: nestedParentScrollViewKey,
scrollDirection: Axis.vertical,
controller: controller,
child: Column(
children: [
Padding(
padding: EdgeInsets.all(40),
child: Text('Nested Demo', style: TextStyle(fontSize: 48)),
),
ListView(
scrollDirection: scrollDirection,
physics: NeverScrollableScrollPhysics(),
shrinkWrap: true,
children: randomList.map<Widget>((data) {
return Padding(
padding: EdgeInsets.all(8),
child: _getRow(data[0], math.max(data[1].toDouble(), 50.0)),
);
}).toList(),
),
],
),
);
}

int counter = -1;
Future _nextCounter() {
setState(() => counter = (counter + 1) % maxCount);
Expand Down
38 changes: 35 additions & 3 deletions lib/scroll_to_index.dart
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@ abstract class AutoScrollController implements ScrollController {
factory AutoScrollController(
{double initialScrollOffset: 0.0,
bool keepScrollOffset: true,
GlobalKey? scrollerWidgetKey,
double? suggestedRowHeight,
ViewportBoundaryGetter viewportBoundaryGetter:
defaultViewportBoundaryGetter,
Expand All @@ -38,6 +39,7 @@ abstract class AutoScrollController implements ScrollController {
return SimpleAutoScrollController(
initialScrollOffset: initialScrollOffset,
keepScrollOffset: keepScrollOffset,
scrollerWidgetKey: scrollerWidgetKey,
suggestedRowHeight: suggestedRowHeight,
viewportBoundaryGetter: viewportBoundaryGetter,
beginGetter: axis == Axis.horizontal ? (r) => r.left : (r) => r.top,
Expand Down Expand Up @@ -92,6 +94,8 @@ abstract class AutoScrollController implements ScrollController {
class SimpleAutoScrollController extends ScrollController
with AutoScrollControllerMixin {
@override
final GlobalKey? scrollerWidgetKey;
@override
final double? suggestedRowHeight;
@override
final ViewportBoundaryGetter viewportBoundaryGetter;
Expand All @@ -103,6 +107,7 @@ class SimpleAutoScrollController extends ScrollController
SimpleAutoScrollController(
{double initialScrollOffset: 0.0,
bool keepScrollOffset: true,
this.scrollerWidgetKey,
this.suggestedRowHeight,
this.viewportBoundaryGetter: defaultViewportBoundaryGetter,
required this.beginGetter,
Expand All @@ -120,6 +125,8 @@ class SimpleAutoScrollController extends ScrollController
class PageAutoScrollController extends PageController
with AutoScrollControllerMixin {
@override
final GlobalKey? scrollerWidgetKey;
@override
final double? suggestedRowHeight;
@override
final ViewportBoundaryGetter viewportBoundaryGetter;
Expand All @@ -132,6 +139,7 @@ class PageAutoScrollController extends PageController
{int initialPage: 0,
bool keepPage: true,
double viewportFraction: 1.0,
this.scrollerWidgetKey,
this.suggestedRowHeight,
this.viewportBoundaryGetter: defaultViewportBoundaryGetter,
AutoScrollController? copyTagsFrom,
Expand All @@ -149,6 +157,7 @@ mixin AutoScrollControllerMixin on ScrollController
implements AutoScrollController {
@override
final Map<int, AutoScrollTagState> tagMap = <int, AutoScrollTagState>{};
GlobalKey? scrollerWidgetKey;
double? get suggestedRowHeight;
ViewportBoundaryGetter get viewportBoundaryGetter;
AxisValueGetter get beginGetter;
Expand Down Expand Up @@ -477,12 +486,35 @@ mixin AutoScrollControllerMixin on ScrollController

final renderBox = ctx.findRenderObject()!;
assert(Scrollable.of(ctx) != null);
final RenderAbstractViewport viewport =
RenderAbstractViewport.of(renderBox)!;
final revealedOffset = viewport.getOffsetToReveal(renderBox, alignment);
final RenderAbstractViewport? viewport = scrollerWidgetKey != null
? _getScrollerWidgetViewPort(scrollerWidgetKey!, renderBox)
: RenderAbstractViewport.of(renderBox);
assert(viewport != null);
final revealedOffset = viewport!.getOffsetToReveal(renderBox, alignment);

return revealedOffset;
}

RenderAbstractViewport? _getScrollerWidgetViewPort(
GlobalKey scrollerWidgetKey,
RenderObject? childItem,
) {
final scrollerWidgetCtx = scrollerWidgetKey.currentContext;
assert(scrollerWidgetCtx != null);
final scrollerRenderBox = scrollerWidgetCtx!.findRenderObject();
RenderAbstractViewport? viewportBeforeController;

while (childItem != null) {
if (childItem == scrollerRenderBox) {
return viewportBeforeController;
}
if (childItem is RenderAbstractViewport) {
viewportBeforeController = childItem;
}
childItem = childItem.parent as RenderObject?;
}
return null;
}
}

void _cancelAllHighlights([AutoScrollTagState? state]) {
Expand Down