Flutter: search lists char by char - list

Question

I have seen the very good code in "Flutter: Searching Through List". However, I have a list for which I would like the user input to be compared char by char from the beginning of list items, and not if the input is contained somewhere in a list item. I.e. if the user inputs "abc", that should be compared to the first 3 chars only of list items. Can someone help on how to revise the code?

Answer 1

Following code will give you search results that starts with the string you give it:
List<String> searchResults = yourList.where((String item)=>item.startsWith('your_search_characters')).toList();
Demo that can be tried to verify your output:
void main() {
List<String> yourList = <String>[
'abcd', 'cabcd','dcabcd', 'abcdefg'
];
List<String> searchResults = yourList.where((String item)=>item.startsWith('ab')).toList();
print(searchResults);
}
Edited:
You can use this whole code just in _ListPersonPageState> build()
Replace:
if(_filteredList[i].personFirstName.toLowerCase().contains(filter.toLowerCase())) {
With:
if(_filteredList[i].personFirstName.toLowerCase().startsWith(filter.toLowerCase())) {
Following is the complete working code for your reference:
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
void main() => runApp(new AdvancedSearch());
class AdvancedSearch extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'List of People',
home: new ListPersonPage(title: 'List of People'),
);
}
}
class ListPersonPage extends StatefulWidget {
ListPersonPage({Key key, this.title}) : super(key: key);
final String title;
#override
_ListPersonPageState createState() => _ListPersonPageState();
}
class _ListPersonPageState extends State<ListPersonPage> {
List<Person> _personList = [];
List<Person> _filteredList = [];
TextEditingController controller = new TextEditingController();
String filter = "";
Widget appBarTitle = new Text("List of People");
Icon actionIcon = new Icon(Icons.search);
#override
void dispose() {
controller.dispose();
super.dispose();
}
#override
void initState() {
PersonDataBuilder pdb = new PersonDataBuilder();
List<Person> tmpList = new List<Person>();
for(int i=0; i < pdb.getPeople().length; i++) {
tmpList.add(pdb.getPeople()[i]);
}
setState(() {
_personList = tmpList;
_filteredList = _personList;
});
controller.addListener(() {
if(controller.text.isEmpty) {
setState(() {
filter = "";
_filteredList = _personList;
});
} else {
setState(() {
filter = controller.text;
});
}
});
super.initState();
}
#override
Widget build(BuildContext context) {
final appTopAppBar = AppBar(
elevation: 0.1,
title: appBarTitle,
actions: <Widget>[
new IconButton(
icon: actionIcon,
onPressed: () {
setState(() {
if (this.actionIcon.icon == Icons.search) {
this.actionIcon = new Icon(Icons.close);
this.appBarTitle = new TextField(
controller: controller,
decoration: new InputDecoration(
prefixIcon: new Icon(Icons.search, color: Colors.white),
hintText: "Search...",
hintStyle: new TextStyle(color: Colors.white),
),
style: new TextStyle(
color: Colors.white,
),
autofocus: true,
cursorColor: Colors.white,
);
} else {
this.actionIcon = new Icon(Icons.search);
this.appBarTitle = new Text("List of People");
_filteredList = _personList;
controller.clear();
}
});
},
),
],
);
ListTile personListTile(Person person) => ListTile(
title: Text(
person.personFirstName + " " + person.personLastName,
style: TextStyle(color: Colors.black45, fontWeight: FontWeight.bold),
),);
Card personCard(Person person) => Card(
child: Container(
decoration: BoxDecoration(color: Colors.grey[300]),
child: personListTile(person),
),
);
if((filter.isNotEmpty)) {
List<Person> tmpList = new List<Person>();
for(int i = 0; i < _filteredList.length; i++) {
if(_filteredList[i].personFirstName.toLowerCase().startsWith(filter.toLowerCase())) {
tmpList.add(_filteredList[i]);
}
}
_filteredList = tmpList;
}
final appBody = Container(
child: ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemCount: _personList == null ? 0 : _filteredList.length,
itemBuilder: (BuildContext context, int index) {
return personCard(_filteredList[index]);
},
),
);
return Scaffold(
appBar: appTopAppBar,
body: appBody,
);
}
}
class PersonDataBuilder {
List getPeople() {
return [
Person(
personFirstName: "John",
personLastName: "Smith"
),
Person(
personFirstName: "Alex",
personLastName: "Johnson"
),
Person(
personFirstName: "Jane",
personLastName: "Doe"
),
Person(
personFirstName: "Eric",
personLastName: "Johnson"
),
Person(
personFirstName: "Michael",
personLastName: "Eastwood"
),
Person(
personFirstName: "Benjamin",
personLastName: "Woods"
),
Person(
personFirstName: "Abraham",
personLastName: "Atwood"
),
Person(
personFirstName: "Anna",
personLastName: "Clack"
),
Person(
personFirstName: "Clark",
personLastName: "Phonye"
),
Person(
personFirstName: "Kerry",
personLastName: "Mirk"
),
Person(
personFirstName: "Eliza",
personLastName: "Wu"
),
Person(
personFirstName: "Jackey",
personLastName: "Lee"
),
Person(
personFirstName: "Kristin",
personLastName: "Munson"
),
Person(
personFirstName: "Oliver",
personLastName: "Watson"
),
];
}
}
class Person {
String personFirstName;
String personLastName;
Person(
{this.personFirstName, this.personLastName}
);
}
I hope this helps, in case of any doubts please comment.
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