类型'int'不是颤振中'key'错误的'String'类型的子类型答案

【问题标题】：type 'int' is not a subtype of type 'String' of 'key' error in flutter类型'int'不是颤振中'key'错误的'String'类型的子类型
【发布时间】：2020-08-11 22:02:23
【问题描述】：

我有一个列表，其中列出了分配给用户的所有任务，如下所示

  @override
  void initState() {
    crudObj.getassignedData().then((results) {
      setState(() {
        Task = results;
      });
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      drawer: newdrawer(),
      appBar: newappbar(),
      body: _TaskList(),
      floatingActionButton: FloatingActionButton(
        foregroundColor: Colors.black54,
        backgroundColor: Colors.blue,
        elevation: 0,
        child: Icon(Icons.add),
        onPressed: () {
          addDialog(context);
        },
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
    );
  }

  // ignore: non_constant_identifier_names
  Widget _TaskList() {
    if (Task != null) {
      return ListView.builder(
        itemCount: Task.documents.length,
        padding: EdgeInsets.all(5.0),
        itemBuilder: (context, i) {
          return new ListTile(
            title: Text(Task.documents[i].data['Title']),
            subtitle: Text(Task.documents[i].data['Summary']),
            onTap: (){
              Navigator.push(context,
              MaterialPageRoute(builder: (context)=>
              taskdetail(Task.documents[i])
              )
              );
            },
          );
        },
      );
    } else {
      return Text('Loading, Please wait..');
    }
  }

}

每个任务在点击时都应该打开一个详细信息页面。

class _taskdetailState extends State<taskdetail> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Details'),
      ),
      body: ListView.builder(itemBuilder: (context,i)
      {
        return ListTile(
          title: Text(widget.documents[i]['Title']),
        );
      }
      ),
    );
  }
}

我收到此错误：

I/flutter ( 5594): The following assertion was thrown building:
I/flutter ( 5594): type 'int' is not a subtype of type 'String' of 'key'
I/flutter ( 5594): 
I/flutter ( 5594): Either the assertion indicates an error in the framework itself, or we should provide substantially
I/flutter ( 5594): more information in this error message to help you determine and fix the underlying cause.
I/flutter ( 5594): In either case, please report this assertion by filing a bug on GitHub:
I/flutter ( 5594):   https://github.com/flutter/flutter/issues/new?template=BUG.md
I/flutter ( 5594): 
I/flutter ( 5594): When the exception was thrown, this was the stack:
I/flutter ( 5594): #0      _taskdetailState.build.<anonymous closure> (package:taskmanager/screens/taskdetail.dart:23:39)
I/flutter ( 5594): #1      SliverChildBuilderDelegate.build (package:flutter/src/widgets/sliver.dart:446:15)
I/flutter ( 5594): #2      SliverMultiBoxAdaptorElement._build.<anonymous closure> (package:flutter/src/widgets/sliver.dart:1260:67)
I/flutter ( 5594): #3      _HashMap.putIfAbsent (dart:collection-patch/collection_patch.dart:139:29)
I/flutter ( 5594): #4      SliverMultiBoxAdaptorElement._build (package:flutter/src/widgets/sliver.dart:1260:26)
I/flutter ( 5594): #5      SliverMultiBoxAdaptorElement.createChild.<anonymous closure> (package:flutter/src/widgets/sliver.dart:1273:55)
I/flutter ( 5594): #6      BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2412:19)
I/flutter ( 5594): #7      SliverMultiBoxAdaptorElement.createChild (package:flutter/src/widgets/sliver.dart:1266:11)
I/flutter ( 5594): #8      RenderSliverMultiBoxAdaptor._createOrObtainChild.<anonymous closure> (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:354:23)
I/flutter ( 5594): #9      RenderObject.invokeLayoutCallback.<anonymous closure> (package:flutter/src/rendering/object.dart:1823:58)
I/flutter ( 5594): #10     PipelineOwner._enableMutationsToDirtySubtrees (package:flutter/src/rendering/object.dart:875:15)
I/flutter ( 5594): #11     RenderObject.invokeLayoutCallback (package:flutter/src/rendering/object.dart:1823:13)
I/flutter ( 5594): #12     RenderSliverMultiBoxAdaptor._createOrObtainChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:343:5)
I/flutter ( 5594): #13     RenderSliverMultiBoxAdaptor.addInitialChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:427:5)
I/flutter ( 5594): #14     RenderSliverList.performLayout (package:flutter/src/rendering/sliver_list.dart:78:12)
I/flutter ( 5594): #15     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #16     RenderSliverEdgeInsetsPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:134:11)
I/flutter ( 5594): #17     RenderSliverPadding.performLayout (package:flutter/src/rendering/sliver_padding.dart:373:11)
I/flutter ( 5594): #18     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #19     RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:410:13)
I/flutter ( 5594): #20     RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:1367:12)
I/flutter ( 5594): #21     RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:1285:20)
I/flutter ( 5594): #22     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #23     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #24     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #25     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #26     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #27     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #28     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #29     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #30     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #31     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #32     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #33     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #34     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #35     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #36     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #37     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #38     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #39     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #40     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #41     MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:163:11)
I/flutter ( 5594): #42     _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:477:7)
I/flutter ( 5594): #43     MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:232:7)
I/flutter ( 5594): #44     RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:391:14)
I/flutter ( 5594): #45     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #46     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #47     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #48     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #49     _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1232:11)
I/flutter ( 5594): #50     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #51     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #52     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #53     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #54     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #55     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #56     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #57     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #58     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #59     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #60     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #61     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #62     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #63     RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 5594): #64     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #65     RenderOffstage.performLayout (package:flutter/src/rendering/proxy_box.dart:3166:14)
I/flutter ( 5594): #66     RenderObject.layout (package:flutter/src/rendering/object.dart:1724:7)
I/flutter ( 5594): #67     RenderStack.performLayout (package:flutter/src/rendering/stack.dart:505:15)
I/flutter ( 5594): #68     RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1584:7)
I/flutter ( 5594): #69     PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:844:18)
I/flutter ( 5594): #70     RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:344:19)
I/flutter ( 5594): #71     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:774:13)
I/flutter ( 5594): #72     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:283:5)
I/flutter ( 5594): #73     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1102:15)
I/flutter ( 5594): #74     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1041:9)
I/flutter ( 5594): #75     SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:957:5)
I/flutter ( 5594): #79     _invoke (dart:ui/hooks.dart:259:10)
I/flutter ( 5594): #80     _drawFrame (dart:ui/hooks.dart:217:3)
I/flutter ( 5594): (elided 3 frames from package dart:async)

【问题讨论】：

我已经运行了你上面的代码，但没有任何结构错误。您应该提供有关Task 数据存储类型的详细信息。所以我可以使用“任务”数据解决您的问题。

标签： firebase flutter flutter-dependencies

【解决方案1】：

你可以试试，

title: Text("${Task.documents[i].data['Title']}"),
subtitle: Text("${Task.documents[i].data['Summary']}"),

【讨论】：

我能够运行 listview 文件而没有任何错误。错误出现在第二个屏幕任务详细信息中。
当我点击列表视图时它不会进入详细页面而是显示上述错误
在详细信息页面中，您传递的是单个数据而不是列表。你可以使用Text("${widget.documents.data['Title']}")获取数据。
得到同样的错误''type 'int' is not a subtype of type 'String' of 'key' error in flutter''
taskdetail 类的构造函数获取哪种类型的数据？打印你在构造函数中得到的数据并告诉我。