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v1: fix TabBarView #5586

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Merged
FeodorFitsner merged 2 commits into from
Aug 22, 2025
Merged

v1: fix TabBarView #5586

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c5b1cf6
fix: improve TabBarView height handling
ndonkoHenri Aug 22, 2025
974738d
add test for nested Tabs
ndonkoHenri Aug 22, 2025
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63 changes: 38 additions & 25 deletions packages/flet/lib/src/controls/tabs.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -157,35 +157,48 @@ class TabBarViewControl extends StatelessWidget {

// Find the TabController from the nearest TabsControl ancestor
final tabsState = context.findAncestorStateOfType<_TabsControlState>();
if (tabsState != null) {
final tabController = tabsState._tabController;
if (tabsState == null) {
return const ErrorControl(
"TabBarView must be used within a Tabs control");
}

final tabController = tabsState._tabController;

Widget buildConstrainedTabView() {
return ConstrainedControl(
control: control,
child: TabBarView(
controller: tabController,
clipBehavior:
control.getClipBehavior("clip_behavior", Clip.hardEdge)!,
viewportFraction: control.getDouble("viewport_fraction", 1.0)!,
children: control.buildWidgets("controls"),
));
}

return LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
if (constraints.maxHeight == double.infinity &&
control.getDouble("height") == null &&
control.getExpand("expand", 0)! <= 0) {
// If expand property was set, we return the result directly.
// Because having Expanded as direct child of LayoutBuilder is not allowed.
if (control.getExpand("expand", 0)! > 0) {
return buildConstrainedTabView();
}

return LayoutBuilder(
builder: (context, constraints) {
final hasFixedHeight = control.getDouble("height") != null;
final hasUnboundedHeight =
constraints.maxHeight == double.infinity && !hasFixedHeight;

if (hasUnboundedHeight) {
return const ErrorControl(
"Error displaying TabBarView: height is unbounded.",
description:
"Set a fixed height, a non-zero expand, or/and place inside "
"a control with bounded height.");
"Error displaying TabBarView: height is unbounded.",
description:
"Set a fixed height, a non-zero expand, or place it inside a control with bounded height.",
);
}

return ConstrainedControl(
control: control,
child: TabBarView(
controller: tabController,
clipBehavior:
control.getClipBehavior("clip_behavior", Clip.hardEdge)!,
viewportFraction: control.getDouble("viewport_fraction", 1.0)!,
children: control.buildWidgets("controls"),
));
});
} else {
return const ErrorControl(
"TabBarView must be used within a Tabs control");
}
return buildConstrainedTabView();
},
);
}
}

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2 changes: 1 addition & 1 deletion sdk/python/examples/controls/tabs/nested.py
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ def main(page: ft.Page):
ft.TabBarView(
expand=True,
controls=[
ft.Text("Main Tab 1 content"),
ft.Tabs(
length=2,
expand=True,
Expand All @@ -41,7 +42,6 @@ def main(page: ft.Page):
],
),
),
ft.Text("Main Tab 1 content"),
],
),
],
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Binary file added sdk/python/packages/flet/integration_tests/controls/golden/macos/tabs/basic.png
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Binary file added sdk/python/packages/flet/integration_tests/controls/golden/macos/tabs/nesting.png
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Binary file removed ...ython/packages/flet/integration_tests/controls/golden/macos/tabs/tabs_basic.png
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77 changes: 64 additions & 13 deletions sdk/python/packages/flet/integration_tests/controls/test_tabs.py
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@


@pytest.mark.asyncio(loop_scope="module")
async def test_tabs_basic(flet_app: ftt.FletTestApp, request):
async def test_basic(flet_app: ftt.FletTestApp, request):
await flet_app.assert_control_screenshot(
name=request.node.name,
expand_screenshot=True,
Expand All @@ -19,20 +19,71 @@ async def test_tabs_basic(flet_app: ftt.FletTestApp, request):
ft.Tab(label="Tab 2", icon=ft.Icons.SETTINGS),
]
),
ft.Container(
ft.TabBarView(
expand=True,
content=ft.TabBarView(
controls=[
ft.Container(
content=ft.Text("This is Tab 1"),
alignment=ft.Alignment.CENTER,
),
ft.Container(
content=ft.Text("This is Tab 3"),
alignment=ft.Alignment.CENTER,
controls=[
ft.Container(
content=ft.Text("This is Tab 1"),
alignment=ft.Alignment.CENTER,
),
ft.Container(
content=ft.Text("This is Tab 3"),
alignment=ft.Alignment.CENTER,
),
],
),
],
),
),
)


@pytest.mark.asyncio(loop_scope="module")
async def test_nesting(flet_app: ftt.FletTestApp, request):
await flet_app.assert_control_screenshot(
name=request.node.name,
expand_screenshot=True,
control=ft.Tabs(
length=2,
expand=True,
selected_index=1,
content=ft.Column(
expand=True,
controls=[
ft.TabBar(
tabs=[
ft.Tab(label=ft.Text("Main Tab 1")),
ft.Tab(label=ft.Text("Main Tab 2")),
],
),
ft.TabBarView(
expand=True,
controls=[
ft.Text("Main Tab 1 content"),
ft.Tabs(
length=2,
expand=True,
content=ft.Column(
expand=True,
controls=[
ft.TabBar(
secondary=True,
tabs=[
ft.Tab(label=ft.Text("SubTab 1")),
ft.Tab(label=ft.Text("SubTab 2")),
],
),
ft.TabBarView(
expand=True,
controls=[
ft.Text("Nested Tab 1 content"),
ft.Text("Nested Tab 2 content"),
],
),
],
),
],
),
),
],
),
],
),
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