Hi，大家好，我是编程小6，很荣幸遇见你，我把这些年在开发过程中遇到的问题或想法写出来，今天说一说
Search SearchDelegate,希望能够帮助你!!!。

• showSuggestions(context)：这个方法显示建议的搜索内容，也就是Widget buildSuggestions(BuildContext context)方法的的调用；

• 2

• Widget buildLeading(BuildContext context):这个方法返回一个控件，显示为搜索框左侧的按钮，一般设置为返回，这里返回一个具有动态效果的返回按钮：

• Widget buildSuggestions(BuildContext context):这个方法返回一个控件，显示为搜索内容区域的建议内容。
• buildResults方法，是搜到到内容后的展现，

showSearch(context: context, delegate: searchBarDelegate()):跳转到搜索界面。

const searchList = ["益阳", "长沙", "衡阳", "郴州", "宁乡"]; const recentSuggest = ["益阳", "长沙"]; 

import 'package:flutter/material.dart'; import 'search_bar_demo.dart'; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData.light(), home: SearchBarDemo()); } } 

import 'package:flutter/material.dart'; import 'asset.dart'; class SearchBarDemo extends StatefulWidget { _SearchBarDemoState createState() => _SearchBarDemoState(); } class _SearchBarDemoState extends State<SearchBarDemo> { @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: Text('SearchBarDemo'), actions: <Widget>[ IconButton( icon: Icon(Icons.search), onPressed: () { showSearch(context: context, delegate: searchBarDelegate()); } // showSearch(context:context,delegate: searchBarDelegate()), ), ])); } } class searchBarDelegate extends SearchDelegate<String> { @override List<Widget> buildActions(BuildContext context) { return [ IconButton( icon: Icon(Icons.clear), onPressed: () => query = "", ) ]; } @override Widget buildLeading(BuildContext context) { return IconButton( icon: AnimatedIcon( icon: AnimatedIcons.menu_arrow, progress: transitionAnimation), onPressed: () => close(context, '')); } @override Widget buildResults(BuildContext context) { return Container( width: 100.0, height: 100.0, child: Card( color: Colors.redAccent, child: Center( child: Text(query), ), ), ); } @override Widget buildSuggestions(BuildContext context) { final suggestionList = query.isEmpty ? recentSuggest : searchList.where((input) => input.startsWith(query)).toList(); return ListView.builder( itemCount: suggestionList.length, itemBuilder: (context, index) => ListTile( title: RichText( text: TextSpan( text: suggestionList[index].substring(0, query.length), style: TextStyle( color: Colors.black, fontWeight: FontWeight.bold), children: [ TextSpan( text: suggestionList[index].substring(query.length), style: TextStyle(color: Colors.grey)) ])), )); } } 

今天的分享到此就结束了，感谢您的阅读，如果确实帮到您，您可以动动手指转发给其他人。