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Fix DropDownButton with no items resulting in RenderFlex overflow (#26143)

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jimshepherd 2019-01-28 13:07:02 -05:00 committed by Hans Muller
parent d5fd57cfbd
commit 74ebdacad5
2 changed files with 52 additions and 23 deletions
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18
packages/flutter/lib/src/material/dropdown.dart
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@ -557,7 +557,7 @@ class DropdownButton<T> extends StatefulWidget {
this.iconSize = 24.0,
this.isDense = false,
this.isExpanded = false,
}) : assert(items == null || value == null || items.where((DropdownMenuItem<T> item) => item.value == value).length == 1),
}) : assert(items == null || items.isEmpty || value == null || items.where((DropdownMenuItem<T> item) => item.value == value).length == 1),
assert(elevation != null),
assert(iconSize != null),
assert(isDense != null),
@ -770,11 +770,17 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
// If value is null (then _selectedIndex is null) or if disabled then we
// display the hint or nothing at all.
final IndexedStack innerItemsWidget = IndexedStack(
index: _enabled ? (_selectedIndex ?? hintIndex) : hintIndex,
alignment: AlignmentDirectional.centerStart,
children: items,
);
final int index = _enabled ? (_selectedIndex ?? hintIndex) : hintIndex;
Widget innerItemsWidget;
if (items.isEmpty) {
innerItemsWidget = Container();
} else {
innerItemsWidget = IndexedStack(
index: index,
alignment: AlignmentDirectional.centerStart,
children: items,
);
}
Widget result = DefaultTextStyle(
style: _textStyle,

57
packages/flutter/test/material/dropdown_test.dart
View file

@ -374,7 +374,7 @@ void main() {
Widget build() => buildFrame(buttonKey: buttonKey, value: value, textDirection: textDirection, onChanged: onChanged);
await tester.pumpWidget(build());
final RenderBox buttonBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBox.attached);
final Offset buttonOriginBeforeTap = buttonBox.localToGlobal(Offset.zero);
@ -388,7 +388,7 @@ void main() {
// The selected dropdown item is both in menu we just popped up, and in
// the IndexedStack contained by the dropdown button. Both of them should
// have the same origin and height as the dropdown button.
final List<RenderObject> itemBoxes = tester.renderObjectList(find.byKey(const ValueKey<String>('two'))).toList();
final List<RenderObject> itemBoxes = tester.renderObjectList<RenderBox>(find.byKey(const ValueKey<String>('two'))).toList();
expect(itemBoxes.length, equals(2));
for (RenderBox itemBox in itemBoxes) {
assert(itemBox.attached);
@ -419,10 +419,10 @@ void main() {
Widget build() => buildFrame(buttonKey: buttonKey, value: 'two', isExpanded: true, onChanged: onChanged);
await tester.pumpWidget(build());
final RenderBox buttonBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBox.attached);
final RenderBox arrowIcon = tester.renderObject(find.byIcon(Icons.arrow_drop_down));
final RenderBox arrowIcon = tester.renderObject<RenderBox>(find.byIcon(Icons.arrow_drop_down));
assert(arrowIcon.attached);
// Arrow icon should be aligned with far right of button when expanded
@ -437,7 +437,7 @@ void main() {
Widget build() => buildFrame(buttonKey: buttonKey, value: value, isDense: true, onChanged: onChanged);
await tester.pumpWidget(build());
final RenderBox buttonBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBox.attached);
await tester.tap(find.text('two'));
@ -504,7 +504,7 @@ void main() {
items: List<String>.generate(/*length=*/ 100, (int index) => index.toString()),
onChanged: onChanged,
));
final RenderBox buttonBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
await tester.tap(find.byKey(buttonKey));
await tester.pumpAndSettle(); // finish the menu animation
@ -519,7 +519,6 @@ void main() {
);
});
testWidgets('Size of DropdownButton with null value', (WidgetTester tester) async {
final Key buttonKey = UniqueKey();
String value;
@ -527,13 +526,12 @@ void main() {
Widget build() => buildFrame(buttonKey: buttonKey, value: value, onChanged: onChanged);
await tester.pumpWidget(build());
final RenderBox buttonBoxNullValue = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBoxNullValue = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBoxNullValue.attached);
value = 'three';
await tester.pumpWidget(build());
final RenderBox buttonBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBox.attached);
// A Dropdown button with a null value should be the same size as a
@ -542,6 +540,33 @@ void main() {
expect(buttonBox.size, equals(buttonBoxNullValue.size));
});
testWidgets('Size of DropdownButton with no items', (WidgetTester tester) async {
// Regression test for https://github.com/flutter/flutter/issues/26419
final Key buttonKey = UniqueKey();
List<String> items;
Widget build() => buildFrame(buttonKey: buttonKey, items: items, onChanged: onChanged);
await tester.pumpWidget(build());
final RenderBox buttonBoxNullItems = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBoxNullItems.attached);
items = <String>[];
await tester.pumpWidget(build());
final RenderBox buttonBoxEmptyItems = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBoxEmptyItems.attached);
items = <String>['one', 'two', 'three', 'four'];
await tester.pumpWidget(build());
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBox.attached);
// A Dropdown button with a null value should be the same size as a
// one with a non-null value.
expect(buttonBox.localToGlobal(Offset.zero), equals(buttonBoxNullItems.localToGlobal(Offset.zero)));
expect(buttonBox.size, equals(buttonBoxNullItems.size));
});
testWidgets('Layout of a DropdownButton with null value', (WidgetTester tester) async {
final Key buttonKey = UniqueKey();
String value;
@ -553,7 +578,7 @@ void main() {
Widget build() => buildFrame(buttonKey: buttonKey, value: value, onChanged: onChanged);
await tester.pumpWidget(build());
final RenderBox buttonBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBox.attached);
// Show the menu.
@ -579,13 +604,12 @@ void main() {
await tester.pumpWidget(build());
expect(find.text('onetwothree'), findsOneWidget);
final RenderBox buttonBoxHintValue = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBoxHintValue = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBoxHintValue.attached);
value = 'three';
await tester.pumpWidget(build());
final RenderBox buttonBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox buttonBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
assert(buttonBox.attached);
// A Dropdown button with a null value and a hint should be the same size as a
@ -714,7 +738,6 @@ void main() {
expect(find.byType(ListView, skipOffstage: false), findsNothing);
});
testWidgets('Semantics Tree contains only selected element', (WidgetTester tester) async {
final SemanticsTester semantics = SemanticsTester(tester);
await tester.pumpWidget(buildFrame(items: menuItems, onChanged: onChanged));
@ -853,14 +876,14 @@ void main() {
await tester.pumpWidget(build(items: menuItems, onChanged: null));
expect(find.text('enabled'), findsNothing);
expect(find.text('disabled'), findsOneWidget);
final RenderBox disabledHintBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox disabledHintBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
// A Dropdown button with a disabled hint should be the same size as a
// one with a regular enabled hint.
await tester.pumpWidget(build(items: menuItems, onChanged: onChanged));
expect(find.text('disabled'), findsNothing);
expect(find.text('enabled'), findsOneWidget);
final RenderBox enabledHintBox = tester.renderObject(find.byKey(buttonKey));
final RenderBox enabledHintBox = tester.renderObject<RenderBox>(find.byKey(buttonKey));
expect(enabledHintBox.localToGlobal(Offset.zero), equals(disabledHintBox.localToGlobal(Offset.zero)));
expect(enabledHintBox.size, equals(disabledHintBox.size));
});