[英]How to call parent widget function from child widget in Flutter
[英]Flutter - how to call child widget's method from parent
假設我們有兩個有狀態的小部件。
ParentWidget(){
}
ChildWidget() {
someMethod(){
// some code, for example setState code
}
}
現在,當我在ParentWidget
使用ChildWidget
時,如何調用someMethod()
?
如果您需要在小部件上調用函數,您可以使用:
context.findAncestorWidgetOfExactType<T>()
如果您需要在該小部件的狀態上調用函數,您可以使用:
context.findRootAncestorStateOfType<T>();
閱讀更多信息:
https://api.flutter.dev/flutter/widgets/BuildContext/findAncestorWidgetOfExactType.html
https://api.flutter.dev/flutter/widgets/BuildContext/findRootAncestorStateOfType.html
這是我使用過的方式。
GlobalKey<ChildWidgetState> globalKey = GlobalKey();
ParentWidget(){
ChildWidget(key: globalKey);
...
globalKey.currentState.someMethod();
}
ChildWidget() {
ChildWidget({Key key}) : super(key: key);
someMethod(){
// some code, for example setState code
}
}
測試代碼
import 'package:flutter/material.dart';
const Color darkBlue = Color.fromARGB(255, 18, 32, 47);
void main() {
runApp(MyApp());
}
GlobalKey<ChildWidgetState> globalKey = GlobalKey();
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark().copyWith(
scaffoldBackgroundColor: darkBlue,
),
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Center(
child: MyWidget(),
),
),
);
}
}
class MyWidget extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Column(
children: [
InkWell(
onTap: () {
globalKey.currentState.someMethod();
},
child: Text('ParentWidget'),
),
ChildWidget(key: globalKey),
],
);
}
}
class ChildWidget extends StatefulWidget {
ChildWidget({Key key}) : super(key: key);
@override
ChildWidgetState createState() => ChildWidgetState();
}
class ChildWidgetState extends State<ChildWidget> {
void someMethod() {
print('someMethod is called');
}
@override
Widget build(BuildContext context) {
return Text('childWidget');
}
}
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