BottomNavigationBar throws exception

[木村哲朗]

Hello. When I tapped red marked area of screenshot, this error occurred. And this is the brief code. Are there any solution?

[error]

Unhandled Exception: 'package:flutter/src/painting/text_painter.dart': Failed assertion: line 881 pos 12: '!_needsLayout': is not true.

...

[code]

Widget build(BuildContext context) {
List body = [
Container(color: Colors.orange,),
Container(color: Colors.black,),
Container(color: Colors.redAccent,),
];
return Scaffold(
  bottomNavigationBar: BottomNavigationBar(
    showSelectedLabels: false,
    showUnselectedLabels: false,
    selectedItemColor: Colors.greenAccent,
    onTap: (index) {
      setState(() {
        this.index = index;
      });
    },
    currentIndex: index,
    items: [
       BottomNavigationBarItem(
         icon: Icon(Icons.add),
         activeIcon: Icon(Icons.check),
         label: 'one',
        ),
         BottomNavigationBarItem(
            icon: Icon(Icons.add),
            activeIcon: Icon(Icons.check),
            label: 'two',
          ),
         BottomNavigationBarItem(
            icon: Icon(Icons.add),
            activeIcon: Icon(Icons.check),
            label: 'three',
          ),
      ],
   ),
   body: body[index],
  );
}

[Suzuki Tomohiro]

Can you paste the entire error message?

What’s the initial value of this.index?

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[木村哲朗]

Thanks for replying to me.

The initial value of index is 0.

[entire error message]

E/flutter (32589): [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: 'package:flutter/src/painting/text_painter.dart': Failed assertion: line 881 pos 12: '!_needsLayout': is not true.

E/flutter (32589): #0      _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:46:39)

E/flutter (32589): #1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:36:5)

E/flutter (32589): #2      TextPainter.getPositionForOffset (package:flutter/src/painting/text_painter.dart:881:12)

E/flutter (32589): #3      RenderParagraph.hitTestChildren (package:flutter/src/rendering/paragraph.dart:456:52)

E/flutter (32589): #4      RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #5      RenderProxyBoxMixin.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:131:19)

E/flutter (32589): #6      RenderTransform.hitTestChildren.<anonymous closure> (package:flutter/src/rendering/proxy_box.dart:2347:22)

E/flutter (32589): #7      BoxHitTestResult.addWithRawTransform (package:flutter/src/rendering/box.dart:826:31)

E/flutter (32589): #8      BoxHitTestResult.addWithPaintTransform (package:flutter/src/rendering/box.dart:751:12)

E/flutter (32589): #9      RenderTransform.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:2343:19)

E/flutter (32589): #10     RenderTransform.hitTest (package:flutter/src/rendering/proxy_box.dart:2337:12)

E/flutter (32589): #11     RenderProxyBoxMixin.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:131:19)

E/flutter (32589): #12     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #13     RenderShiftedBox.hitTestChildren.<anonymous closure> (package:flutter/src/rendering/shifted_box.dart:92:25)

E/flutter (32589): #14     BoxHitTestResult.addWithPaintOffset (package:flutter/src/rendering/box.dart:787:31)

E/flutter (32589): #15     RenderShiftedBox.hitTestChildren (package:flutter/src/rendering/shifted_box.dart:87:21)

E/flutter (32589): #16     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #17     RenderBoxContainerDefaultsMixin.defaultHitTestChildren.<anonymous closure> (package:flutter/src/rendering/box.dart:2775:25)

E/flutter (32589): #18     BoxHitTestResult.addWithPaintOffset (package:flutter/src/rendering/box.dart:787:31)

E/flutter (32589): #19     RenderBoxContainerDefaultsMixin.defaultHitTestChildren (package:flutter/src/rendering/box.dart:2770:33)

E/flutter (32589): #20     RenderFlex.hitTestChildren (package:flutter/src/rendering/flex.dart:1072:12)

E/flutter (32589): #21     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #22     RenderShiftedBox.hitTestChildren.<anonymous closure> (package:flutter/src/rendering/shifted_box.dart:92:25)

E/flutter (32589): #23     BoxHitTestResult.addWithPaintOffset (package:flutter/src/rendering/box.dart:787:31)

E/flutter (32589): #24     RenderShiftedBox.hitTestChildren (package:flutter/src/rendering/shifted_box.dart:87:21)

E/flutter (32589): #25     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #26     RenderProxyBoxMixin.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:131:19)

E/flutter (32589): #27     RenderProxyBoxWithHitTestBehavior.hitTest (package:flutter/src/rendering/proxy_box.dart:178:19)

E/flutter (32589): #28     RenderProxyBoxMixin.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:131:19)

E/flutter (32589): #29     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #30     RenderProxyBoxMixin.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:131:19)

E/flutter (32589): #31     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #32     RenderMouseRegion.hitTest (package:flutter/src/rendering/proxy_box.dart:2905:18)

E/flutter (32589): #33     RenderProxyBoxMixin.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:131:19)

E/flutter (32589): #34     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #35     RenderBoxContainerDefaultsMixin.defaultHitTestChildren.<anonymous closure> (package:flutter/src/rendering/box.dart:2775:25)

E/flutter (32589): #36     BoxHitTestResult.addWithPaintOffset (package:flutter/src/rendering/box.dart:787:31)

E/flutter (32589): #37     RenderBoxContainerDefaultsMixin.defaultHitTestChildren (package:flutter/src/rendering/box.dart:2770:33)

E/flutter (32589): #38     RenderStack.hitTestChildren (package:flutter/src/rendering/stack.dart:620:12)

E/flutter (32589): #39     RenderBox.hitTest (package:flutter/src/rendering/box.dart:2414:11)

E/flutter (32589): #40     RenderProxyBoxMixin.hitTestChildren (package:flutter/src/rendering/proxy_box.dart:131:19)

E/flutter (32589): #41     RenderBox.hitTest (package:flutter/src/rend

I/ViewRootImpl(32589): ViewRoot's Touch Event : ACTION_DOWN

I/ViewRootImpl(32589): ViewRoot's Touch Event : ACTION_UP

[Suzuki Tomohiro]

Can you try this?

    showSelectedLabels: true,
    showUnselectedLabels: true,

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[木村哲朗]

It worked! But the labels were shown. So, I changed labelStyle's fontSize and height to 0. Then no error occurred and the bar became what I want.

Thanks!

[Ming Jun Siek]

I also have the same issue and this solution works. But I don't understand why it works. Why is setting both selected and unselected labels to false cause the error?