将gif从关闭后重新打开后重新开始

Question

我正在尝试使该gif在单击浮动操作按钮时出现，并在按下ok后再次弹出它：https://66.media.tumblr.com/1ce23970665b7736bd857720ebf5a5b2/tumblr_pp3sftPVIy1wb1n5x_540.gif问题是，当我单击“确定”并重新单击浮动操作按钮时，gif将从上次按“确定”时停止停止。我希望每次单击浮动操作按钮时都从头开始。我怎样才能做到这一点？这是代码：

floatingActionButton: FloatingActionButton(
          child: Icon(Icons.healing),

          onPressed: () {
            showDialog(
              context: context,
              builder: (_) => Container(
                height: 200.0,
                child: NetworkGiffyDialog(
                  // key: keys[1],
                  image: Image.network(
                    gif,
                    fit: BoxFit.fitHeight,
                  ),
                  title: Text("Exercises of breathing"),
                  description: Text(
                    'This will help you with breathing exercises to overcome anxiety attacks',
                  ),
                  entryAnimation: EntryAnimation.RIGHT,
                  onOkButtonPressed: () {
                    Navigator.of(context).pop();
                  },
                ),
              ),
            );
          },
          //child: new Text("Breathing exercise"),
        ),

EDIT：我遵循第一个答案，并尝试如下在null值和gif链接之间进行切换，但是我仍然遇到相同的问题

floatingActionButton: FloatingActionButton(
          child: Icon(Icons.healing),

          onPressed: () {
            setState(() => gif = giflink);
            showDialog(
              context: context,
              builder: (_) => Container(
                height: 200.0,
                child: NetworkGiffyDialog(
                  // key: keys[1],
                  image: Image.network(
                    gif,
                    fit: BoxFit.fitHeight,
                  ),
                  title: Text("Exercises of breathing"),
                  description: Text(
                    'This will help you with breathing exercises to overcome anxiety attacks',
                  ),
                  entryAnimation: EntryAnimation.RIGHT,
                  onOkButtonPressed: () {
                    Navigator.of(context).pop();
                    setState(() => gif = null);
                  },
                ),
              ),
            );
          },
          //child: new Text("Breathing exercise"),
        ),

Answer 1