how to find mobile small mobile screen in flutter code example

Example: how to get the display size of mobile display in flutter

getHeightWidth(context){
 
    double width = MediaQuery.of(context).size.width;
 
    double height = MediaQuery.of(context).size.height;
 
    setState(() {
     heightHolder = height.roundToDouble();
     widthHolder = width.roundToDouble() ; 
    });
 
  }