问题
今天使用横向布局row 并且在里面添加了一个图标和一行文字，但是总是会超出布局，即使设置了overflow再调试时也会出现如下的情况
Row(
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Image.asset(
"images/list_icon.png",
width: 10,
height: 10,
fit: BoxFit.fill,
),
Text(
" "+hotService[index]['servicename'],
maxLines: 1,
style: TextStyle(
fontSize: 14,
decoration: TextDecoration.none),
overflow: TextOverflow.ellipsis,
)
],
),
6D6EE3FE-B336-4475-ABD6-863075236C33.png
解决方法
直接在Text文字外面包一层Expanded（之前初学时，直接将Row改成Flex，因为Row继承自Flex，所以不用替换外层感谢周南城指出来）
Row(
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Image.asset(
"images/list_icon.png",
width: 10,
height: 10,
fit: BoxFit.fill,
),
Expanded(child: Text(
" "+hotService[index]['servicename'],
maxLines: 1,
style: TextStyle(
fontSize: 14,
decoration: TextDecoration.none),
overflow: TextOverflow.ellipsis,
))
],
),
解决后如图所示
6FF0A039-8FA4-4308-9B70-91B711B49A3E.png
出现问题的原因
因为刚开始学习，不是很了解，应该是横向row没有确定宽度，text根据内容来撑开row，所以就会超出，换成flex 使text最大宽度能占用剩下的所有宽度，所以达到最宽的时候就会显示省略号。
这个错误就好像再column中使用listView一样，会出现一个在无限高度的view中使用listView的错误,这个错误代码如下
Column(
children: <Widget>[
ListView.builder(
itemBuilder: (BuildContext con, int index) {
return Text("index");
},
itemCount: 10,
//下面的注释打开，可以解除报错
//shrinkWrap: true,
)
],
),
//会出现的错误
I/flutter (18787): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter (18787): The following assertion was thrown during performResize():
I/flutter (18787): Vertical viewport was given unbounded height.
I/flutter (18787): Viewports expand in the scrolling direction to fill their container.In this case, a vertical
I/flutter (18787): viewport was given an unlimited amount of vertical space in which to expand. This situation
I/flutter (18787): typically happens when a scrollable widget is nested inside another scrollable widget.
I/flutter (18787): If this widget is always nested in a scrollable widget there is no need to use a viewport because
I/flutter (18787): there will always be enough vertical space for the children. In this case, consider using a Column
I/flutter (18787): instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
I/flutter (18787): the height of the viewport to the sum of the heights of its children.
- 解决column 嵌套listview的方法就是设置shrinkWrap，
shrinkWrap：该属性表示是否根据子widget的总长度来设置ListView的长度，默认值为false 。默认情况下，ListView的会在滚动方向尽可能多的占用空间。当ListView在一个无边界(滚动方向上)的容器中时，shrinkWrap必须为true
