Widget and CupertinoWidget : avoid code duplicate

How to avoid code duplication when we want Platform specific Widget for Android and Cupertino Widget for iOS like Switch ?

       @override
      Widget build(BuildContext context) {
        return Scaffold(
            appBar: AppBar(),
            body: (Platform.isAndroid)
                ? Switch(
                   value: activate,
                   onChanged: (value) {
                    setState(() {
                      activate = value;
                    });
                   },
                 )
                : CupertinoSwitch(
                   value: activate,
                   onChanged: (value) {
                    setState(() {
                     activate = value;
                    });
                   },
                 )
              );
             }