错误：参数类型“上下文”不能分配给参数类型“BuildContext”

Posted 2023-03-27

【中文标题】错误：参数类型“上下文”不能分配给参数类型“BuildContext”

【英文标题】：error: The argument type 'Context' can't be assigned to the parameter type 'BuildContext'

【发布时间】：2020-04-01 05:36:50

【问题描述】：

此编译错误：错误：无法将参数类型“Context”分配给参数类型“BuildContext”（argument_type_not_assignable at [tter] lib\Pages\list_view.dart:95）

不知道为什么突然出现这个错误 该应用程序运行良好，但我的代码中仍然出现错误 这是我的代码：

import 'package:path/path.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:tter/utilities/database_helper.dart';
TextEditingController searchText = TextEditingController();
class CardsListView extends StatefulWidget 
  int whereComeFrom;
  CardsListView(this.whereComeFrom);
  @override
  CardsListViewState createState() => CardsListViewState(whereComeFrom);


class CardsListViewState extends State<CardsListView> 
  int whereComeFrom;
  CardsListViewState(this.whereComeFrom);
  var db = DatabaseHelper();
  List mainList = [];
  _showDialog() 
    showDialog(
        context: context,
        builder: (BuildContext context)
          return StatefulBuilder(
            builder: (context,sett)
              void _showSearchReturn(String query) async
              
              return  Container(
              );
            ,
          );
        
    );
  

  @override
  Widget build(BuildContext context)
    return Container();
  

【问题讨论】：

你能评论一下错误在哪里吗？此外，您可以使用widget.whereComeFrom 来获取值，您不需要通过构造函数传递它。

此处显示对话框下的错误：context : context

【参考方案1】：

State 提供的上下文不是最佳选择。我建议将 BuildContext 传递给 _showDialog() 方法。我已经发布了下面的代码向您展示。我也这样做了，这样您就不需要 State 类中的构造函数了。

import 'package:path/path.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:tter/utilities/database_helper.dart';
TextEditingController searchText = TextEditingController();

class CardsListView extends StatefulWidget 
  final int whereComeFrom; // immutable class, should be declared as final for all variables
  CardsListView(this.whereComeFrom);
  @override
  CardsListViewState createState() => CardsListViewState();


class CardsListViewState extends State<CardsListView> 
  // IMPORTANT! You can use widget.whereComeFrom to get the value.
  // You DON'T need to pass a variable to the state.
  var db = DatabaseHelper();
  List mainList = [];
  // Pass an actual BuildContext here.
  // The context given from State isn't the best option.
  // If you call this from a Builder, just pass the context.
  _showDialog(BuildContext context) 
    showDialog(
        context: context,
        builder: (BuildContext context)
          return StatefulBuilder(
            builder: (context,sett)
              void _showSearchReturn(String query) async
              
              return  Container(
              );
            ,
          );
        
    );
  

  @override
  Widget build(BuildContext context)
    return Container();