Question

我创建了一个有状态的窗口小部件，以显示包含搜索栏的“警报”对话框，但是搜索栏文本在键入时不会更新，并且保持空白。我已将文本字段的控制器设置为TextEditingController（），但仍无法正常工作。

代码

import 'package:flutter/material.dart';
import 'package:flutter_convertor/Data Models/Society.dart';

class MyDialogContent extends StatefulWidget {

  @override
  _MyDialogContentState createState() => new _MyDialogContentState();
}

class _MyDialogContentState extends State<MyDialogContent> {

  @override
  void initState(){

    super.initState();
  }

  @override
  Widget build(BuildContext context) {

    //Search bar

    Container searchBar = Container(
      child: Padding(
        padding: const EdgeInsets.only(left: 0.0, right: 0.0),
        child: TextField(
          onChanged: (value) {
            filterSearchResults(value);
          },
          controller: TextEditingController(),
          decoration: InputDecoration(
              labelText: "Search",
              prefixIcon: Icon(Icons.search),
              border: OutlineInputBorder(
                  borderRadius: BorderRadius.all(Radius.circular(15.0)))),
        ),
      ),
    );


    AlertDialog dialog = AlertDialog(
      title: searchBar,
      content: Container(
   ....
      ),
    );



    return dialog;
  }
}

控制器在我的主dart文件中工作。但是当我放入“警报对话框”状态控件

Answer 1

此方法与您使用的方法相同，将不起作用

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';

class Sample extends StatefulWidget {
  @override
  _SampleState createState() => new _SampleState();
}

class _SampleState extends State<Sample> {
  List<String> countries = <String>['Belgium','France','Italy','Germany','Spain','Portugal'];
  int _selectedCountryIndex = 0;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_){_showDialog();});
  }

  _buildList(){
    if (countries.length == 0){
      return new Container();
    }

    return new Column(
      children: new List<RadioListTile<int>>.generate(
        countries.length,
        (int index){
          return new RadioListTile<int>(
            value: index,
            groupValue: _selectedCountryIndex,
            title: new Text(countries[index]),
            onChanged: (int value) {
              setState((){
                _selectedCountryIndex = value;
              });
            },
          );
        }
      )
    );
  }

  _showDialog() async{
    await showDialog<String>(
      context: context,
      builder: (BuildContext context){
        return new CupertinoAlertDialog(
          title: new Text('Please select'),
          actions: <Widget>[
            new CupertinoDialogAction(
              isDestructiveAction: true,
              onPressed: (){Navigator.of(context).pop('Cancel');},
              child: new Text('Cancel'),
            ),
            new CupertinoDialogAction(
              isDestructiveAction: true,
              onPressed: (){Navigator.of(context).pop('Accept');},
              child: new Text('Accept'),
            ),
          ],
          content: new SingleChildScrollView(
            child: new Material(
              child: _buildList(),
            ),
          ),
        );
      },
      barrierDismissible: false,
    );
  }

  @override
  Widget build(BuildContext context) {
    return new Container();
  }
}

您应该像下面这样

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';

class Sample extends StatefulWidget {
  @override
  _SampleState createState() => new _SampleState();
}

class _SampleState extends State<Sample> {
  List<String> countries = <String>['Belgium','France','Italy','Germany','Spain','Portugal'];

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_){_showDialog();});
  }

  _showDialog() async{
    await showDialog<String>(
      context: context,
      builder: (BuildContext context){
        return new CupertinoAlertDialog(
          title: new Text('Please select'),
          actions: <Widget>[
            new CupertinoDialogAction(
              isDestructiveAction: true,
              onPressed: (){Navigator.of(context).pop('Cancel');},
              child: new Text('Cancel'),
            ),
            new CupertinoDialogAction(
              isDestructiveAction: true,
              onPressed: (){Navigator.of(context).pop('Accept');},
              child: new Text('Accept'),
            ),
          ],
          content: new SingleChildScrollView(
            child: new Material(
              child: new MyDialogContent(countries: countries),
            ),
          ),
        );
      },
      barrierDismissible: false,
    );
  }

  @override
  Widget build(BuildContext context) {
    return new Container();
  }
}

class MyDialogContent extends StatefulWidget {
  MyDialogContent({
    Key key,
    this.countries,
  }): super(key: key);

  final List<String> countries;

  @override
  _MyDialogContentState createState() => new _MyDialogContentState();
}

class _MyDialogContentState extends State<MyDialogContent> {
  int _selectedIndex = 0;

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

  _getContent(){
    if (widget.countries.length == 0){
      return new Container();
    }

    return new Column(
      children: new List<RadioListTile<int>>.generate(
        widget.countries.length,
        (int index){
          return new RadioListTile<int>(
            value: index,
            groupValue: _selectedIndex,
            title: new Text(widget.countries[index]),
            onChanged: (int value) {
              setState((){
                _selectedIndex = value;
              });
            },
          );
        }
      )
    );
  }

  @override
  Widget build(BuildContext context) {
    return _getContent();
  }
}

TextField TextController在有状态窗口小部件内不起作用

1 个答案: