Flutter/Dart - 滑动动画的反向？

Question

我从 Flutter.dev 网站获得了以下示例。它提供了流畅的 onSwipeUp 动画。但是我怎样才能修改代码给我一个流畅的 onSwipeDown 动画呢？我尝试颠倒 var begin 和 var end，但它似乎没有成功，当我滑动时没有任何反应。这是刷卡码；

onSwipeDown: (){
           Navigator.of(context).push(_opidRoute(routeaudioid: opid));
            },

这是动画；

    Route _opidRoute({String routeaudioid, String mastertitle}) {
  return PageRouteBuilder(
    opaque: false,
    pageBuilder: (context, animation, secondaryAnimation) => SingleOpid(opid: routeaudioid
    ),
    transitionsBuilder: (context, animation, secondaryAnimation, child) {
      var begin = Offset(0.0, 1.0);
      var end = Offset.zero;
      var curve = Curves.ease;

      var tween = Tween(begin: begin, end: end).chain(CurveTween(curve: curve));

      return SlideTransition(
        position: animation.drive(tween),
        child: child,
      );
    },
  );
}

有什么办法可以反转方向吗？

Answer 1

尝试

var begin = Offset(0.0, -1.0);

Flutter/Dart - 滑动动画的反向？

Flutter/Dart - Reverse Direction of Swipe Animation?

dart

flutter

flutter-layout

flutter-animation