Question

我是Flutter的初学者，目前正在关注构建任务计划器（https://www.youtube.com/watch?v=xJSestoFlJ8&list=PLF9bFmu3NqWqchwS3DO9MDSl15IiHQWcr&index=9）的教程

手动重写代码（数据库等）后，当我重新启动应用程序以显示在调试控制台中保存到数据库中的项目时，在使用initstate和setstate时出现错误提示

Unhandled Exception: type 'String' is not a subtype of type 'int' of 'index'

这是与错误相关的代码

final TextEditingController _textEditingController = TextEditingController();
  var db = DatabaseHelper();

  @override
  void initState() {
    super.initState();

    _readTaskList();
  }

  void _handleSubmitted(String text) async {
    _textEditingController.clear();

    Tasks tasksItem = Tasks(text, DateTime.now().toIso8601String());
    int savedItemId = await db.saveItem(tasksItem);

    print("Item saved ID: $savedItemId");

  }

_readTaskList() async {
    List items = await db.getItems();
    items.forEach((item) {
      Tasks tasksItem = Tasks.map(items);
      print("DB Items: ${tasksItem.itemName}");
    });
  }

这是完整的调试控制台日志

E/flutter ( 8249): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: type 'String' is not a subtype of type 'int' of 'index'
E/flutter ( 8249): #0      new Tasks.map 
package:gatorblocks_rbt/models/tasks.dart:12
E/flutter ( 8249): #1      _TaskPlannerState._readTaskList.<anonymous closure> 
package:gatorblocks_rbt/pages/taskPlanner.dart:105
E/flutter ( 8249): #2      List.forEach  (dart:core-patch/growable_array.dart:285:8)
E/flutter ( 8249): #3      _TaskPlannerState._readTaskList 
package:gatorblocks_rbt/pages/taskPlanner.dart:104
E/flutter ( 8249): <asynchronous suspension>
E/flutter ( 8249): #4      _TaskPlannerState.initState 
package:gatorblocks_rbt/pages/taskPlanner.dart:24
E/flutter ( 8249): #5      StatefulElement._firstBuild 
package:flutter/…/widgets/framework.dart:4355
E/flutter ( 8249): #6      ComponentElement.mount 
package:flutter/…/widgets/framework.dart:4201
E/flutter ( 8249): #7      Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #8      Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #9      SingleChildRenderObjectElement.mount 
package:flutter/…/widgets/framework.dart:5445
E/flutter ( 8249): #10     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #11     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #12     ComponentElement.performRebuild 
package:flutter/…/widgets/framework.dart:4243
E/flutter ( 8249): #13     Element.rebuild 
package:flutter/…/widgets/framework.dart:3947
E/flutter ( 8249): #14     ComponentElement._firstBuild 
package:flutter/…/widgets/framework.dart:4206
E/flutter ( 8249): #15     ComponentElement.mount 
package:flutter/…/widgets/framework.dart:4201
E/flutter ( 8249): #16     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #17     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #18     SingleChildRenderObjectElement.mount 
package:flutter/…/widgets/framework.dart:5445
E/flutter ( 8249): #19     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #20     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #21     SingleChildRenderObjectElement.mount 
package:flutter/…/widgets/framework.dart:5445
E/flutter ( 8249): #22     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #23     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #24     ComponentElement.performRebuild 
package:flutter/…/widgets/framework.dart:4243
E/flutter ( 8249): #25     Element.rebuild 
package:flutter/…/widgets/framework.dart:3947
E/flutter ( 8249): #26     ComponentElement._firstBuild 
package:flutter/…/widgets/framework.dart:4206
E/flutter ( 8249): #27     StatefulElement._firstBuild 
package:flutter/…/widgets/framework.dart:4381
E/flutter ( 8249): #28     ComponentElement.mount 
package:flutter/…/widgets/framework.dart:4201
E/flutter ( 8249): #29     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #30     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #31     SingleChildRenderObjectElement.mount 
package:flutter/…/widgets/framework.dart:5445
E/flutter ( 8249): #32     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #33     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #34     SingleChildRenderObjectElement.mount 
package:flutter/…/widgets/framework.dart:5445
E/flutter ( 8249): #35     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #36     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #37     ComponentElement.performRebuild 
package:flutter/…/widgets/framework.dart:4243
E/flutter ( 8249): #38     Element.rebuild 
package:flutter/…/widgets/framework.dart:3947
E/flutter ( 8249): #39     ComponentElement._firstBuild 
package:flutter/…/widgets/framework.dart:4206
E/flutter ( 8249): #40     StatefulElement._firstBuild 
package:flutter/…/widgets/framework.dart:4381
E/flutter ( 8249): #41     ComponentElement.mount 
package:flutter/…/widgets/framework.dart:4201
E/flutter ( 8249): #42     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 8249): #43     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 8249): #44     ComponentElement.performRebuild 
package:flutter/…/widgets/framework.dart:4243
E/flutter ( 8249): #45     Element.rebuild (package:flutte

Here is a screenshot

该应用程序运行正常，不会崩溃或发生任何事情，只是无法正确显示我已保存到数据库中的项目。

Answer 1

由于将int放入接受Text的{{1}}小部件中而收到错误消息。

您可以通过使用String方法转换int来解决此问题。

检查以下代码：将其替换为toString()函数：

handleSubmitted

我希望这会有所帮助。

已更新 看完代码后，我可以看到您正在尝试访问void _handleSubmitted(String text) async { _textEditingController.clear(); Tasks tasksItem = Tasks(text, DateTime.now().toIso8601String()); int savedItemId = await db.saveItem(tasksItem); // convert savedItemId to a string using toString() method print("Item saved ID: $savedItemId.toString()"); }构造函数中未定义的字段id。为什么会出现错误： Tasks

希望这可以解决您的错误。

Flutter / Dart-未处理的异常：“字符串”类型不是“索引”的“ int”类型的子类型

1 个答案: