Expand area of CupertinoNavigationBar leading


I am using CupertinoNavigationBar to make a layout expected like image below

enter image description here

In left side/leading area, I override default back button to create the layout, but instead I got an overflow

enter image description here

return CupertinoPageScaffold(
  leading: Row(
    children: <Widget>[
      UtomoDeckNavigationBar.getDefaultBackButton(context: context, isLightTheme: true),
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
              style: TextStyle(
                color: CupertinoColors.black,
                fontWeight: FontWeight.bold,
                fontSize: 14.0)),
              style: TextStyle(color: CupertinoColors.black, fontSize: 12.0))

and the error

Performing hot reload...
Syncing files to device iPhone SE...
flutter: ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
flutter: The following assertion was thrown during layout:
flutter: A RenderFlex overflowed by 34 pixels on the right.
flutter: The overflowing RenderFlex has an orientation of Axis.horizontal.
flutter: The edge of the RenderFlex that is overflowing has been marked in the rendering with a yellow and
flutter: black striped pattern. This is usually caused by the contents being too big for the RenderFlex.
flutter: Consider applying a flex factor (e.g. using an Expanded widget) to force the children of the
flutter: RenderFlex to fit within the available space instead of being sized to their natural size.
flutter: This is considered an error condition because it indicates that there is content that cannot be
flutter: seen. If the content is legitimately bigger than the available space, consider clipping it with a
flutter: ClipRect widget before putting it in the flex, or using a scrollable container rather than a Flex,
flutter: like a ListView.
flutter: The specific RenderFlex in question is: RenderFlex#d650f relayoutBoundary=up2 OVERFLOWING:
flutter:   creator: Row ← IconTheme ← Builder ← Padding ← KeyedSubtree-[GlobalKey#fab21 Leading] ←
flutter:     LayoutId-[<_ToolbarSlot.leading>] ← CustomMultiChildLayout ← NavigationToolbar ← Padding ←
flutter:     MediaQuery ← Padding ← SafeArea ← ⋯
flutter:   parentData: offset=Offset(16.0, 0.0) (can use size)
flutter:   constraints: BoxConstraints(0.0<=w<=90.7, h=44.0)
flutter:   size: Size(90.7, 44.0)
flutter:   direction: horizontal
flutter:   mainAxisAlignment: start
flutter:   mainAxisSize: max
flutter:   crossAxisAlignment: center
flutter:   textDirection: ltr
flutter:   verticalDirection: down
flutter: ◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤◢◤
flutter: ════════════════════════════════════════════════════════════════════════════════════════════════════
Reloaded 11 of 687 libraries in 407ms.

Can I expand the constraint of the leading area, or maybe there’s a better approach to do this?

Thank you.


to solve this, I use Row with MainAxisAlignment.start inside middle instead of leading.


Use Container with infinity width instead of Row, its children will overflow if its children widgets are more than the parent (Row), and TextOverflow.ellipsis won’t help

Answered By – Ampersanda

Answer Checked By – David Marino (FlutterFixes Volunteer)

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