android - 如何为某个小部件 Flutter 指定拖动目标(单个 Draggable 被放入 3 个拖动目标而不是 1 个)
问题描述
这是我面临的问题:
我从一个表情符号列表开始,我想将其放入这 3 个放置目标中
当我拖动其中一个表情符号时(只有一个,在这种情况下是第一个,它会自动落入所有拖动目标,而不仅仅是第一个)。
这会导致相同的表情符号无意中填充所有拖动目标,这是意想不到的行为:
我的问题是,如何更改我的代码,以确保当我将表情符号拖动到第一个、第二个或第三个拖动目标时,只有相应的拖动目标被填充而不是全部填充?非常感谢,我非常感谢您的帮助!
拖动框代码:
class DragBox extends StatefulWidget {
DragBox({this.animatedAsset, this.width});
final LottieBuilder animatedAsset;
final double width;
@override
_DragBoxState createState() => _DragBoxState();
}
class _DragBoxState extends State<DragBox> {
@override
Widget build(BuildContext context) {
return Draggable(
feedback: Container(
width: 50,
height: 50,
child: widget.animatedAsset,
),
child: Container(
child: widget.animatedAsset,
width: widget.width,
height: 50,
),
childWhenDragging: Container(),
data: widget.animatedAsset,
);
}
}
表情符号选择器代码:
class AnimatedEmojiPicker extends StatefulWidget {
@override
_AnimatedEmojiPickerState createState() => _AnimatedEmojiPickerState();
}
class _AnimatedEmojiPickerState extends State<AnimatedEmojiPicker> {
@override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.only(left: 10.0, right: 10.0),
child: Container(
width: MediaQuery.of(context).size.width,
height: 60,
decoration:
BoxDecoration(color: Colors.grey.shade400.withOpacity(0.5), borderRadius: BorderRadius.circular(20.0)),
child: ListView(
scrollDirection: Axis.horizontal,
children: <Widget>[
Container(
width: 15,
),
DragBox(
animatedAsset: Lottie.asset('Assets/blushing.json'),
),
Container(
width: 15,
),
DragBox(
animatedAsset: Lottie.asset('Assets/cooldude.json'),
),
Container(
width: 15,
),
DragBox(
animatedAsset: Lottie.asset('Assets/zipmouth.json'),
),
//More drag boxes like this one
],
),
),
);
}
}
我的拖动目标:
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
DragTarget(
onAccept: (LottieBuilder animation) {
setState(() {
widget.caughtAnimation = animation;
});
},
builder: (BuildContext context, List<dynamic> candidateData, List<dynamic> rejectedData) {
return Center(
child: Container(
height: 60,
width: 60,
decoration: BoxDecoration(
color: Colors.grey.shade400.withOpacity(0.5), borderRadius: BorderRadius.circular(20.0)),
child: widget.caughtAnimation,
),
);
},
),
Padding(
padding: const EdgeInsets.all(8.0),
child: DragTarget(
onAccept: (LottieBuilder animation) {
setState(() {
widget.caughtAnimation = animation;
});
},
builder: (BuildContext context, List<dynamic> candidateData, List<dynamic> rejectedData) {
return Center(
child: Container(
height: 60,
width: 60,
decoration: BoxDecoration(
color: Colors.grey.shade400.withOpacity(0.5),
borderRadius: BorderRadius.circular(20.0)),
child: widget.caughtAnimation,
),
);
},
),
),
DragTarget(
onAccept: (LottieBuilder animation) {
setState(() {
widget.caughtAnimation = animation;
});
},
builder: (BuildContext context, List<dynamic> candidateData, List<dynamic> rejectedData) {
return Center(
child: Container(
height: 60,
width: 60,
decoration: BoxDecoration(
color: Colors.grey.shade400.withOpacity(0.5), borderRadius: BorderRadius.circular(20.0)),
child: widget.caughtAnimation,
),
);
},
),
],
),
再次感谢您的帮助!
解决方案
发生这种情况是因为您在每个回调上DragTarget
都构建了与widget.caughtAnimation
您在任何onAccept
回调上设置的相同的内容。
考虑以您可以单独修改每个 DragTarget 的方式构建小部件状态模型,这可以通过列表/数组或地图来完成。
List<LottieBuilder> caughtAnimations;
然后
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
DragTarget(
onAccept: (LottieBuilder animation) {
setState(() {
caughtAnimations[0] = animation;
});
},
builder: (BuildContext context, List<dynamic> candidateData, List<dynamic> rejectedData) {
return Center(
child: Container(
height: 60,
width: 60,
decoration: BoxDecoration(
color: Colors.grey.shade400.withOpacity(0.5), borderRadius: BorderRadius.circular(20.0)),
child: caughtAnimations[0],
),
);
},
),
Padding(
padding: const EdgeInsets.all(8.0),
child: DragTarget(
onAccept: (LottieBuilder animation) {
setState(() {
caughtAnimations[1] = animation;
});
},
builder: (BuildContext context, List<dynamic> candidateData, List<dynamic> rejectedData) {
return Center(
child: Container(
height: 60,
width: 60,
decoration: BoxDecoration(
color: Colors.grey.shade400.withOpacity(0.5),
borderRadius: BorderRadius.circular(20.0)),
child: caughtAnimations[1],
),
);
},
),
),
DragTarget(
onAccept: (LottieBuilder animation) {
setState(() {
caughtAnimations[2] = animation;
});
},
builder: (BuildContext context, List<dynamic> candidateData, List<dynamic> rejectedData) {
return Center(
child: Container(
height: 60,
width: 60,
decoration: BoxDecoration(
color: Colors.grey.shade400.withOpacity(0.5), borderRadius: BorderRadius.circular(20.0)),
child: caughtAnimations[2],
),
);
},
),
],
),
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