Implementation of basic flutter search bar failed - flutter

Question

So I followed a tutorial on how to implement a basic Flutter search bar with search Delegation. You can find the tutorial on this link: https://www.youtube.com/watch?v=FPcl1tu0gDs
class DataSearch extends SearchDelegate<String>{
final wordssuggest=["Word1","Word2"];
final recentwords=["Word1"];
#override
List<Widget> buildActions(BuildContext context){
return [
IconButton(onPressed: (){
query=" ";
}, icon: Icon(Icons.clear))
];
//actions for appbar
}
#override
Widget buildLeading(BuildContext context){
return IconButton(onPressed: (){
close(context, null);
}, icon: Icon(Icons.search));
//leasding icon on the left of the app bar
}
#override
Widget buildResults(BuildContext context){
//show some result
return Container(
color: Colors.grey,
height: 200,
width: 200,
child: Center(child: Text(query),)
);
}
#override
Widget buildSuggestions(BuildContext context){
//show suggestions
final suggestionList =query.isEmpty?
recentwords:wordssuggest.where((p)=>p.startsWith(query)).toList();
return ListView.builder(itemBuilder: (context, index)=>ListTile(
onTap:(){
showResults(context);
} ,
leading: Icon(Icons.work_rounded),
title: RichText(text: TextSpan(text: suggestionList[index].substring(0, query.length),
style: TextStyle(color:Colors.blue, fontWeight: FontWeight.bold),
children: [TextSpan(
text:suggestionList[index].substring(query.length),
style:TextStyle(color:Colors.grey)
)]),
)
),
itemCount: suggestionList.length,);
}
}
However, what is not working for me:
For SearchDelegate method in the DataSearch class:
'Methods must have an explicit list of parameters.Try adding a parameter list.dart(missing_method_parameters)'
For buildActions, buildLeading, builduggestions and buildResults Widgets:
'The declaration 'buildActions' isn't referenced.'
Inside buildSuggestions:
The method 'showResults' isn't defined for the type '_MainPageState'.
Inside buildLeading:
The method 'close' isn't defined for the type '_MainPageState'.
Please help

Answer 1

Maybe your problem is occur because of calling the search delegate class.
this code solve your problem!
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Secondpage(title: 'Flutter Demo Home Page'),
);
}
}
class Secondpage extends StatelessWidget {
final String title;
Secondpage({required this.title});
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(title),
actions: [
IconButton(icon: Icon(Icons.add), onPressed: () async {
await showSearch<String>(
context: context,
delegate: DataSearch(),
);
},
)
],
));
}
}
Search Delegate
class DataSearch extends SearchDelegate<String>{
final wordSuggest=["Word1","Word2","Word3","Word4", "Word5","Word6", ];
final recentWords=["Word1"];
#override
List<Widget> buildActions(BuildContext context) {
return [
IconButton(
icon: Icon(Icons.clear),
onPressed: () {
query = "";
// showSuggestions(context);
},
),
];
}
#override
Widget buildLeading(BuildContext context) {
return IconButton(
onPressed: () {
close(context, 'null');
},
icon: AnimatedIcon(
icon: AnimatedIcons.menu_arrow,
progress: transitionAnimation,
),
);
}
#override
Widget buildResults(BuildContext context){
//show some result
return Container(
color: Colors.grey,
height: 200,
width: 200,
child: Center(child: Text(query),)
);
}
#override
Widget buildSuggestions(BuildContext context){
//show suggestions
final suggestionList =query.isEmpty?
recentWords:wordSuggest.where((p)=>p.startsWith(query)).toList();
return ListView.builder(itemBuilder: (context, index)=>ListTile(
onTap:(){
showResults(context);
} ,
leading: Icon(Icons.work_rounded),
title: RichText(text: TextSpan(text: suggestionList[index].substring(0, query.length),
style: TextStyle(color:Colors.blue, fontWeight: FontWeight.bold),
children: [TextSpan(
text:suggestionList[index].substring(query.length),
style:TextStyle(color:Colors.grey)
)]),
)
),
itemCount: suggestionList.length,);
}
}