NSNotificationCenter：为什么要调用removeObserver？ [英] NSNotificationCenter: Why bother calling removeObserver?
问题描述
上帝已经改变了许多习惯进入我孤立的丛林村庄，例如：
The gods have parachuted many habits into my isolated jungle village, such as:
- (void) dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
[super dealloc];
}
他们的方式对我很奇怪，理解他们。
Their ways are strange to me, yet I still seek to understand them.
为什么要清理松散的东西，如果实例离开呢？该实例的引用/保留计数不会递减？它会隐藏某种类型的通知哈希表，其中包含所有监听器的列表。
Why bother cleaning loose ends up if the instance is going away? Will the reference/retain count to that instance not be decremented? Will it clutter some sort of Notification Hash Table lurking out there that holds a list of all the listeners?
推荐答案
NSNotificationCenter 不保留观察器。如果你不删除观察者，并且观察者被释放，那么 NSNotificationCenter 就会留下一个悬空指针，当它下一次尝试通知观察员。
NSNotificationCenter doesn't retain observers. If you don't remove the observer, and the observer is deallocated, then NSNotificationCenter is left holding a dangling pointer which will (most often) crash when it next tries to notify the observer.
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