<p dir="auto">This most likely is me doing something wrong. However, I thought I had this working... I get this error when trying to add a column with content to an ExpansionPanel. The error only occurs at runtime when I try to expand more than one panel at a time. The app is a simple one inspired by the holidays. It is a simple Holiday Shopping List. It contains an image and text in the top 40% of the page. In the remaining 60% or so, it contains a ListView with a Container -&gt;Column&gt;Row-&gt;Columns. The app is laid out as a dynamically generated list of Giftees (people we are shopping for), each contains a sub-list of gifts (gift we may purchase. I want to embed an few IconButtons but the Panel header can't handle that. It runs out of room. So I removed them.</p>
<p dir="auto">If you need the code for this. let me know.</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="[+12406 ms] I/flutter (23691): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
[   +4 ms] I/flutter (23691): The following assertion was thrown building ExpansionPanelList:
[        ] I/flutter (23691): 'package:flutter/src/material/mergeable_material.dart': Failed assertion: line 441: '_children[j] is
[        ] I/flutter (23691): MaterialGap': is not true.
[  +12 ms] I/flutter (23691):
[        ] I/flutter (23691): Either the assertion indicates an error in the framework itself, or we should provide substantially
[        ] I/flutter (23691): more information in this error message to help you determine and fix the underlying cause.
[        ] I/flutter (23691): In either case, please report this assertion by filing a bug on GitHub:
[        ] I/flutter (23691):   https://github.com/flutter/flutter/issues/new
[        ] I/flutter (23691):
[        ] I/flutter (23691): When the exception was thrown, this was the stack:
[  +10 ms] I/flutter (23691): #2      _MergeableMaterialState.didUpdateWidget (package:flutter/src/material/mergeable_material.dart:441)
[        ] I/flutter (23691): #3      StatefulElement.update (package:flutter/src/widgets/framework.dart:3677)
[        ] I/flutter (23691): #4      Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #5      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #6      Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #7      StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #8      Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #9      SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #10     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #11     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #12     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #13     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #14     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #15     StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #16     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #17     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #18     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #19     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #20     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #21     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #22     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #23     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #25     SliverMultiBoxAdaptorElement.performRebuild (package:flutter/src/widgets/sliver.dart:696)
[        ] I/flutter (23691): #26     SliverMultiBoxAdaptorElement.update (package:flutter/src/widgets/sliver.dart:665)
[        ] I/flutter (23691): #27     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #28     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #29     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #30     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #31     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #32     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #33     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #34     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:4261)
[        ] I/flutter (23691): #35     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4647)
[        ] I/flutter (23691): #36     _ViewportElement.update (package:flutter/src/widgets/viewport.dart:182)
[        ] I/flutter (23691): #37     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #39     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #40     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #41     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #42     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #43     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #44     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #45     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #46     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #47     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #48     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #49     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #50     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #51     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #52     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #53     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #54     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #55     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #56     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #57     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #58     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[   +1 ms] I/flutter (23691): #59     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #60     StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #61     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #62     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #63     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #64     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #65     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #66     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #67     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #68     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #69     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #70     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #71     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #72     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #73     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #74     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #75     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #76     StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #77     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #78     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #79     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #80     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2193)
[   +2 ms] I/flutter (23691): #81     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding&amp;PaintingBinding&amp;RendererBinding&amp;WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:611)
[        ] I/flutter (23691): #82     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding&amp;PaintingBinding&amp;RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:203)
[        ] I/flutter (23691): #83     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:916)
[        ] I/flutter (23691): #84     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:856)
[        ] I/flutter (23691): #85     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:768)
[        ] I/flutter (23691): #86     _invoke (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:113)
[        ] I/flutter (23691): #87     _drawFrame (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:102)
[   +5 ms] I/flutter (23691): (elided 2 frames from class _AssertionError)
[        ] I/flutter (23691): ════════════════════════════════════════════════════════════════════════════════════════════════════"><pre class="notranslate"><code class="notranslate">[+12406 ms] I/flutter (23691): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
[   +4 ms] I/flutter (23691): The following assertion was thrown building ExpansionPanelList:
[        ] I/flutter (23691): 'package:flutter/src/material/mergeable_material.dart': Failed assertion: line 441: '_children[j] is
[        ] I/flutter (23691): MaterialGap': is not true.
[  +12 ms] I/flutter (23691):
[        ] I/flutter (23691): Either the assertion indicates an error in the framework itself, or we should provide substantially
[        ] I/flutter (23691): more information in this error message to help you determine and fix the underlying cause.
[        ] I/flutter (23691): In either case, please report this assertion by filing a bug on GitHub:
[        ] I/flutter (23691):   https://github.com/flutter/flutter/issues/new
[        ] I/flutter (23691):
[        ] I/flutter (23691): When the exception was thrown, this was the stack:
[  +10 ms] I/flutter (23691): #2      _MergeableMaterialState.didUpdateWidget (package:flutter/src/material/mergeable_material.dart:441)
[        ] I/flutter (23691): #3      StatefulElement.update (package:flutter/src/widgets/framework.dart:3677)
[        ] I/flutter (23691): #4      Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #5      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #6      Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #7      StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #8      Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #9      SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #10     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #11     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #12     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #13     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #14     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #15     StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #16     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #17     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #18     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #19     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #20     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #21     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #22     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #23     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #25     SliverMultiBoxAdaptorElement.performRebuild (package:flutter/src/widgets/sliver.dart:696)
[        ] I/flutter (23691): #26     SliverMultiBoxAdaptorElement.update (package:flutter/src/widgets/sliver.dart:665)
[        ] I/flutter (23691): #27     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #28     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #29     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #30     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #31     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #32     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #33     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #34     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:4261)
[        ] I/flutter (23691): #35     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4647)
[        ] I/flutter (23691): #36     _ViewportElement.update (package:flutter/src/widgets/viewport.dart:182)
[        ] I/flutter (23691): #37     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #39     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #40     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #41     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #42     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #43     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #44     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #45     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #46     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #47     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #48     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #49     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #50     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #51     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #52     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #53     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #54     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #55     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #56     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4539)
[        ] I/flutter (23691): #57     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #58     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[   +1 ms] I/flutter (23691): #59     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #60     StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #61     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #62     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #63     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #64     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #65     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #66     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #67     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #68     StatefulElement.update (package:flutter/src/widgets/framework.dart:3681)
[        ] I/flutter (23691): #69     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #70     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #71     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #72     ProxyElement.update (package:flutter/src/widgets/framework.dart:3791)
[        ] I/flutter (23691): #73     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #74     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #75     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #76     StatelessElement.update (package:flutter/src/widgets/framework.dart:3606)
[        ] I/flutter (23691): #77     Element.updateChild (package:flutter/src/widgets/framework.dart:2649)
[        ] I/flutter (23691): #78     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3556)
[        ] I/flutter (23691): #79     Element.rebuild (package:flutter/src/widgets/framework.dart:3445)
[        ] I/flutter (23691): #80     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2193)
[   +2 ms] I/flutter (23691): #81     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding&amp;PaintingBinding&amp;RendererBinding&amp;WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:611)
[        ] I/flutter (23691): #82     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding&amp;PaintingBinding&amp;RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:203)
[        ] I/flutter (23691): #83     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:916)
[        ] I/flutter (23691): #84     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:856)
[        ] I/flutter (23691): #85     BindingBase&amp;GestureBinding&amp;ServicesBinding&amp;SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:768)
[        ] I/flutter (23691): #86     _invoke (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:113)
[        ] I/flutter (23691): #87     _drawFrame (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:102)
[   +5 ms] I/flutter (23691): (elided 2 frames from class _AssertionError)
[        ] I/flutter (23691): ════════════════════════════════════════════════════════════════════════════════════════════════════
</code></pre></div>
<h2 dir="auto">Steps to Reproduce</h2>
<p dir="auto">Please tell us what you were doing and what went wrong. If you are running flutter tools from the command line, please try adding the <code class="notranslate">-v</code> or <code class="notranslate">--verbose</code> option to gather more information.</p>
<p dir="auto">If the problem is with your application's rendering, please attach a screenshot and any relevant source code.<br>
If you are getting an exception in the logs, and your code is implicated in the first few frames, then please include the source code for the functions involved.</p>
<h2 dir="auto">Logs</h2>
<p dir="auto">Run your application with <code class="notranslate">flutter run</code> and attach all the log output.</p>
<p dir="auto">Run <code class="notranslate">flutter analyze</code> and attach any output of that command also.</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="dev:~/projects/flutter/holiday_shoping_list$ flutter analyze
Analyzing /home/projects/flutter/holiday_shoping_list...
No issues found!Ran in 4.9s"><pre class="notranslate"><code class="notranslate">dev:~/projects/flutter/holiday_shoping_list$ flutter analyze
Analyzing /home/projects/flutter/holiday_shoping_list...
No issues found!Ran in 4.9s
</code></pre></div>
<h2 dir="auto">Flutter Doctor</h2>
<p dir="auto">Paste the output of running <code class="notranslate">flutter doctor</code> here.</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="$ flutter doctor[✓] Flutter (on Linux, locale en_US.UTF-8, channel alpha)
    • Flutter at /home/randy/flutter    • Framework revision 8f65fec5f5 (2 weeks ago), 2017-12-12 09:50:14 -0800
    • Engine revision edaecdc8b8    • Tools Dart version 1.25.0-dev.11.0
    • Engine Dart version 2.0.0-edge.d8ae797298c3a6cf8dc9f4558707bd2672224d3e
[✓] Android toolchain - develop for Android devices (Android SDK 27.0.1)
    • Android SDK at /home/randy/Android/Sdk
    • Android NDK at /home/randy/Android/Sdk/ndk-bundle
    • Platform android-27, build-tools 27.0.1
    • Java binary at: /opt/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b01)

[✓] Android Studio (version 3.0)
    • Android Studio at /opt/android-studio
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b01)

[-] IntelliJ IDEA Community Edition (version 15)
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • For information about installing plugins, see
      https://flutter.io/intellij-setup/#installing-the-plugins
    ✗ This install is older than the minimum recommended version of 2017.1.0.

[-] IntelliJ IDEA Community Edition (version 13)
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • For information about installing plugins, see
      https://flutter.io/intellij-setup/#installing-the-plugins
    ✗ This install is older than the minimum recommended version of 2017.1.0.

[✓] IntelliJ IDEA Community Edition (version 2017.2)
    • Flutter plugin version 19.1
    • Dart plugin version 172.4343.25

[✓] Connected devices
    • Android SDK built for x86 • emulator-5554 • android-x86 • Android 8.1.0 (API 27) (emulator)
"><pre class="notranslate"><code class="notranslate">$ flutter doctor[✓] Flutter (on Linux, locale en_US.UTF-8, channel alpha)
    • Flutter at /home/randy/flutter    • Framework revision 8f65fec5f5 (2 weeks ago), 2017-12-12 09:50:14 -0800
    • Engine revision edaecdc8b8    • Tools Dart version 1.25.0-dev.11.0
    • Engine Dart version 2.0.0-edge.d8ae797298c3a6cf8dc9f4558707bd2672224d3e
[✓] Android toolchain - develop for Android devices (Android SDK 27.0.1)
    • Android SDK at /home/randy/Android/Sdk
    • Android NDK at /home/randy/Android/Sdk/ndk-bundle
    • Platform android-27, build-tools 27.0.1
    • Java binary at: /opt/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b01)

[✓] Android Studio (version 3.0)
    • Android Studio at /opt/android-studio
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b01)

[-] IntelliJ IDEA Community Edition (version 15)
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • For information about installing plugins, see
      https://flutter.io/intellij-setup/#installing-the-plugins
    ✗ This install is older than the minimum recommended version of 2017.1.0.

[-] IntelliJ IDEA Community Edition (version 13)
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • For information about installing plugins, see
      https://flutter.io/intellij-setup/#installing-the-plugins
    ✗ This install is older than the minimum recommended version of 2017.1.0.

[✓] IntelliJ IDEA Community Edition (version 2017.2)
    • Flutter plugin version 19.1
    • Dart plugin version 172.4343.25

[✓] Connected devices
    • Android SDK built for x86 • emulator-5554 • android-x86 • Android 8.1.0 (API 27) (emulator)

</code></pre></div>
<blockquote>
<p dir="auto">For more information about diagnosing and reporting Flutter bugs, please see <a href="https://flutter.io/bug-reports/" rel="nofollow">https://flutter.io/bug-reports/</a>.</p>
</blockquote>
<p dir="auto">Hi, I'm trying to use the <code class="notranslate">url_launcher 0.4.1</code> plugging but Im getting the following exception when tryin to launch an URL, I just upgraded to flutter 1.0 via <code class="notranslate">flutter upgrade</code></p>
<p dir="auto">any ideas what could be causing this?</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="MissingPluginException(No implementation found for method canLaunch on channel plugins.flutter.io/url_launcher)
#0      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:291:7)
&lt;asynchronous suspension&gt;
#1      canLaunch (package:url_launcher/url_launcher.dart:88:25)
&lt;asynchronous suspension&gt;
#2      PostWidget.build._launchURL (package:app/post.dart:66:17)
&lt;asynchronous suspension&gt;
#3      PostWidget.build.&lt;anonymous closure&gt; (package:app/post.dart:107:44)
#4      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:507:14)
#5      _InkResponseState.build.&lt;anonymous closure&gt; (package:flutter/src/material/ink_well.dart:562:30)
#6      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24)
#7      TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:242:9)
#8      TapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:204:7)"><pre class="notranslate"><code class="notranslate">MissingPluginException(No implementation found for method canLaunch on channel plugins.flutter.io/url_launcher)
#0      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:291:7)
&lt;asynchronous suspension&gt;
#1      canLaunch (package:url_launcher/url_launcher.dart:88:25)
&lt;asynchronous suspension&gt;
#2      PostWidget.build._launchURL (package:app/post.dart:66:17)
&lt;asynchronous suspension&gt;
#3      PostWidget.build.&lt;anonymous closure&gt; (package:app/post.dart:107:44)
#4      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:507:14)
#5      _InkResponseState.build.&lt;anonymous closure&gt; (package:flutter/src/material/ink_well.dart:562:30)
#6      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24)
#7      TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:242:9)
#8      TapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:204:7)
</code></pre></div>