Question

我试图在另一个名为SwipeButton的onDragEnd函数中从Map类的Map类调用一个函数（addGeoPoint），这两个函数都是有状态的。

class Map extends StatefulWidget {
//Some Code
  _MapState createState() => _MapState();
}

class _MapState extends State<Map> {
//Some Functions

void addGeoPoint() async{
}

文件2

class SwipeButton extends StatefulWidget {

// Some Code

  @override
  SwipeButtonState createState() => SwipeButtonState();
}

class SwipeButtonState extends State<SwipeButton>
    with SingleTickerProviderStateMixin {

// Some functions
void _onDragEnd(DragEndDetails details) {
   // I want to call the addGeoPoint() function here 

}

}

为此，我尝试将Map类的实例创建为Map mapScreen = new Map，然后使用mapScreen.addGeoPoint()访问该函数，但是没有成功。解决该问题的任何帮助将不胜感激。

Answer 1

您可以使用VoidCallBacks在小部件之间进行通信：

地图：

class Map extends StatefulWidget {
//Some Code
  _MapState createState() => _MapState();
}

class _MapState extends State<Map> {
//Some Functions

void addGeoPoint() async{
  //do things
}

Widget buildSwipeButton() {
    ...
    ...
    return SwipeButton(
      onAddGeoPoint: addGeoPoint,
    );
}

SwipeButton：

class SwipeButton extends StatefulWidget {

final VoidCallback onAddGeopoint;

SwipeButton({this.onAddGeoPoint});

// Some Code

  @override
  SwipeButtonState createState() => SwipeButtonState();
}

class SwipeButtonState extends State<SwipeButton>
    with SingleTickerProviderStateMixin {

// Some functions
void _onDragEnd(DragEndDetails details) {
   // I want to call the addGeoPoint() function here 
   widget.onAddGeoPoint();
}

}

Answer 2

您可以这样声明小部件

class YourWidget extends StatefulWidget {
  final Function callback;

  YourWidget({@required this.textButton});

  @override
  YourWidgetState createState() => YourWidgetState();
}

然后您可以在有状态的父级中传递这样的功能

YourWidget(
   callback: (){}
)

ant，然后您就可以在YourWidget中像在其他小部件或其他功能中一样使用

widget.callback()

如何从另一个StatefulWidget调用StatefulWidget中的函数？

2 个答案: