/**
* Stack是层叠布局相当于Android中的absolutelayout或者RelativityLayout
* Stack的布局根据child分为positioned和non-positioned两种，
* positioned根据left，top，right，bottom来设置widget的位置，相对于组件左上角
* non-positioned则根据alignment来设置widget位置。
* Stack的子widget，先添加的在布局下层，后添加的在布局上层
Stack({
Key key,
this.alignment = AlignmentDirectional.topStart, //对齐方式，alignment配合FractionalOffset,占据的百分比
this.textDirection,
this.fit = StackFit.loose,
this.overflow = Overflow.clip,//超过的部分是否裁剪掉
List<Widget> children = const <Widget>[],
})
*/
Stack(
fit: StackFit.loose,
// alignment: AlignmentDirectional.topCenter,
alignment: FractionalOffset(0.9, 0.5),
children: <Widget>[
Container(
width: 100.0,
height: 100.0,
margin: EdgeInsets.only(right: 20.0,top: 10.0),
color: Color(0xff00ff00),
),
Center(
child: GestureDetector(child: Text("按钮",
style: TextStyle(
decoration: TextDecoration.lineThrough,
fontSize: 18.0,
fontWeight: FontWeight.bold,
color: Color(0xffff0000),
),),
onTap: () {
print("按钮");
},
),
),
],
)
Stack(
children: <Widget>[
Container(
width: 200.0,
height: 100.0,
color: Color(0xfff1f1f1),
),
Positioned(
child: GestureDetector(child: Text("按钮",
style: TextStyle(
decoration: TextDecoration.lineThrough,
fontSize: 18.0,
fontWeight: FontWeight.bold,
color: Color(0xffff0000),
),),
onTap: () {
print("按钮");
},),
left: 10.0,
top: 20.0,
)
],
),
