删除Self作为观察者时崩溃-CALayer-CrashWhenRemovingSelfasObserver-CALayer

I am having a crash in my CALayer subclass when I remove myself as an observer in -(void)dealloc:

当我在 - （void）dealloc中以观察者身份移除自己时，我的CALayer子类崩溃了：

- (void)dealloc {
 [[NSUserDefaults standardUserDefaults] removeObserver:self forKeyPath:@"showColorLabels"];
 [colorLabel release];
 [_color release];
 [super dealloc];
}

An exception is thrown. It says that self has not been added as an observer. This only happens in a certain case, after [CATransaction flush] is called.

抛出异常。它说自我没有被添加为观察者。这只发生在某种情况下，在调用[CATransaction flush]之后。

I used Instruments to see when the object was allocated. It says it was allocated with the call CALayerGetPresentationLayer(). I am not sure how this works, but I guess this is a copy of my original layer, so init was never called, and I was never added as an observer.

我使用Instruments来查看对象的分配时间。它说它是通过调用CALayerGetPresentationLayer（）分配的。我不确定这是如何工作的，但我想这是我原始图层的副本，因此从未调用过init，我从未被添加为观察者。

How can I either check that I am an observer before removing myself, or maybe tell if I am a presentation layer?

如何在删除自己之前检查我是观察者，还是告诉我是否是表示层？

Bridger Maxwell

Bridger Maxwell

2 个解决方案

@try{
   [[NSUserDefaults standardUserDefaults] removeObserver:self forKeyPath:@"showColorLabels"];
}@catch(id anException){
   //Whatever you want to do.
}