ios - uicollectionviewcell自适应问题

Question

我在storyboard添加collectionview和cell，设置了约束。我有添加header和footer，而且有种cell，都有约束，但是问题来了：
1、header和footer的高度怎么自适应呢，控件里有个collection reusable view 的size属性，似乎在这里是写死的？我去~~说好的自适应呢
2、cell添加了约束，我在cell里面添加了一个imageview，添加了各种约束，可是在预览和模拟器里面看都不正常，cell的高度和宽度都不对。
求高手指点，collectionview不是很会用。
在storyboard设置如图，蓝色的时一个cell：

在预览中看到是这样的：

模拟器中是这样的：

不知道是什么情况，请高手指点一下。谢谢~~

Answer 1

Finally, the sizes of cell, header and footer are realized through three methods: collectionView:layout:sizeForItemAtIndexPath:, collectionView:layout:referenceSizeForHeaderInSection:, collectionView:layout:referenceSizeForFooterInSection:. It seems that it cannot be completely determined by the storyboard settings. yes? no? Wait for the experts to answer.

Answer 2

Although I don’t quite understand it, I think you must make sure that the sub-controls in your headerview cell have been set up before the view is rendered. If you add sub-controls to the headerview cell after the view is rendered, they probably won’t be able to. Adaptable