如何从子小部件调用父小部件中的函数 |扑

Posted 2023-02-23

【中文标题】如何从子小部件调用父小部件中的函数 |扑

【英文标题】：How to Call a function in parent widget from child widget | Flutter

【发布时间】：2021-12-30 01:55:52

【问题描述】：

我有一个父子小部件。父小部件具有功能。我想从我的子小部件中调用该函数（myParentFunction）。这是父小部件，

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。我如何重写此代码以获得该功能。

【参考方案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();
      ,
    );
  

【参考方案2】：

您应该传递函数并在子窗口小部件中调用

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,
    );