KVO，BUG问题An instance 0x151dbfd20

BUG:

An instance 0x151dbfd20 of class XXX was deallocated while key value observers were still registered with it. Current observation info:( Context: 0x0, Property: 0x170859a40> )

对象释放了但是没有释放他的KVO，当时刷新UI时remove了一个设置KVO的视图，需在设置KVO视图remove前将观察者移除掉；[youView removeObserver:self forKeyPath:@"keyPath"];。当控制器移除时也需要调移除观察者。- (void)dealloc{[youView removeObserver:self forKeyPath:@"keyPath"];}