iOS 9 控制台出现提示信息

“This application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes. This will cause an exception in a future release.”

为什么呢？代理回调的方法中有UI的更新造成的，

Apple have started (with iOS 9) detecting when you’re doing this and warning you.

处理代码

dispatch_async(dispatch_get_main_queue(), ^{
    // code here
});