listView嵌套GridView可能会出现如下错误:
Vertical viewport was given unbounded height.
分析原因可能是因为 尝试通过子组件的实际尺寸来调整自身尺寸，这就导致他们的子组件不能是延迟加载模型的组件（如ListView、GridView 、 CustomScrollView等）,解决办法就是把内部无限高度设置自动收缩,或者增加一个高度.
转载:
flutter中的ListView组件和GridView组件都是常用的布局组件，有时候ListView中需要嵌套GridView来使用，例如下图：
这种情况就需要在ListView里面再嵌套一个GridView用于排放图片等信息，先来看一下GridView一些常用的参数
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GridView.count( crossAxisCount: 3, // 每行显示多少个 crossAxisSpacing: 1.5, // 横轴网格间距 mainAxisSpacing: 1.5, // 纵轴网格间距 childAspectRatio: 11/16, // 网格比例) |
在GridView中的元素无法设置其宽高，主要通过childAspectRatio来设置其比例，通过比例来显示其大小。
在项目中如果直接使用ListView嵌套GridView进行布局，其会出现报错异常，例如下面异常：
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I/flutter ( 5969): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════I/flutter ( 5969): The following assertion was thrown during performResize():I/flutter ( 5969): Vertical viewport was given unbounded height.I/flutter ( 5969): Viewports expand in the scrolling direction to fill their container.In this case, a verticalI/flutter ( 5969): viewport was given an unlimited amount of vertical space in which to expand. This situationI/flutter ( 5969): typically happens when a scrollable widget is nested inside another scrollable widget.I/flutter ( 5969): If this widget is always nested in a scrollable widget there is no need to use a viewport becauseI/flutter ( 5969): there will always be enough vertical space for the children. In this case, consider using a ColumnI/flutter ( 5969): instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to sizeI/flutter ( 5969): the height of the viewport to the sum of the heights of its children. |
出现这种情况可在GridView中设置shrinkWrap:true即可解决：
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GridView.count( shrinkWrap:true, // 处理listview嵌套报错), |
此时有可能出现手指在GridView区域滑动时ListView无法进行滚动，处理该问题可在GridView中设置physics: NeverScrollableScrollPhysics()来处理：
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GridView.count( physics: NeverScrollableScrollPhysics(), // 处理GridView中滑动父级Listview无法滑动) |
