如何从子窗口小部件| Flutter调用父窗口小部件中的函数

Question

我有一个父子小部件。父窗口小部件有一个功能。我想从我的子窗口小部件调用那个函数(myParentFunction(。这是父窗口小部件

class ParentWidget extends StatelessWidget {
void myParentFunction() {
print("This is print from parent");
}
@override
Widget build(BuildContext context) {
return Center(
child: MyCustomButton(),
);
}
}

这是子窗口小部件

class MyCustomButton extends StatelessWidget {
void myChildFunction() {
print("This is print from child");
//Here i want to call the myParentFunction()
}
@override
Widget build(BuildContext context) {
return ElevatedButton(
child: Text('Press'),
onPressed: () {
newFunction();
},
);
}
}

这里的预期结果是，当我按下"按下"按钮时，我希望输出为This is print from child This is print from parent。我如何重写这些代码以获得该功能。

Answer 1

使用回调函数

class ParentWidget extends StatelessWidget {
void myParentFunction() {
print("This is print from parent");
}
@override
Widget build(BuildContext context) {
return Center(
child: MyCustomButton(
callback: () {
myParentFunction();
},
),
);
}
}
class MyCustomButton extends StatelessWidget {
final VoidCallback callback;
MyCustomButton({
Key? key,
required this.callback,
}) : super(key: key);
void myChildFunction() {
print("This is print from child");
//Here i want to call the myParentFunction()
}
@override
Widget build(BuildContext context) {
return ElevatedButton(
child: Text('Press'),
onPressed: () {
callback();
},
);
}
}

Answer 2

您应该传递函数并调用子窗口小部件

class ParentWidget extends StatelessWidget {
void myParentFunction() {
print("This is print from parent");
}
@override
Widget build(BuildContext context) {
return Center(
child: MyCustomButton(myParentFunction),
);
}
}
class MyCustomButton extends StatelessWidget {
final Function onTap;
MyCustomButton(this.onTap);
@override
Widget build(BuildContext context) {
return ElevatedButton(
child: Text('Press'),
onPressed: onTap,
);
}
}