ios – 集合视图上的奇怪的自动布局行为

我有一个autolayout的问题,控制台报告问题,我有一个单元格中的图像视图：

RefreshCatalogue[31754:16177989] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand,refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSLayoutConstraint:0x7fa98103b740 V:[UIImageView:0x7fa9810375d0]-(0)-|   (Names: '|':UIView:0x7fa9810371d0 )>","<NSLayoutConstraint:0x7fa98103b7e0 V:|-(0)-[UIImageView:0x7fa9810375d0]   (Names: '|':UIView:0x7fa9810371d0 )>","<NSLayoutConstraint:0x7fa98103b8d0 UIImageView:0x7fa9810375d0.centerY == UIImageView:0x7fa981037490.centerY>","<NSLayoutConstraint:0x7fa98103ba60 UIImageView:0x7fa981037490.top == UIView:0x7fa9810371d0.topMargin + 71>","<NSAutoresizingMaskLayoutConstraint:0x7fa980d44a10 h=--& v=--& V:[UIView:0x7fa9810371d0(50)]>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x7fa98103b8d0 UIImageView:0x7fa9810375d0.centerY == UIImageView:0x7fa981037490.centerY>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

问题是如果我这样做：

[self.collectionView reloadItemsAtIndexPaths:@[indexPath]];

没有什么显示甚至图像视图似乎有正确的框架,图像属性设置.
如果我重新加载整个集合视图：

[self.collectionView reloadData];

错误仍然存​​在,但图像显示.代码在这里开放,任何人都有兴趣看看：
https://github.com/Ridiculous-Innovations/RefreshCatalogue

此外,故事板中的所有限制似乎都是蓝色的.任何想法可能导致这个问题？

编辑：不用说,所有的元素,包括图像视图在正确的地方(我做了调试框架和设置随机颜色),但图像没有显示,直到刷新…有时,单元格根本不显示

解决方法

您有UIImageView的问题：0x7fa981037490.top == UIView：0x7fa9810371d0.topMargin 71和父帧为0高(所以imageview高度必须为负,但不允许),就像右键调用dequeueReusableCell方法. 对于这种情况,可能的解决方法是将嵌套视图(垂直空间 – catalogueHeaderCell – 图像视图和垂直空间 – catalogueCell – 信息视图)的最底层约束的更改优先级从1000到999.