ios - 注销后，我得到 "class deallocated while key value observers were still registered with it"

Question

我有一些适用于许多对象的代码，将我的类注册为 KVO:

for (SPPanelManager *manager in self.panelManagers) {
    [manager addObserver:self forKeyPath:@"dataFetchComplete" options:0 context:NULL];
    [manager fetchData];
}

然后当它观察到发生在每个这些对象上的变化时，我取消注册:

-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString:@"dataFetchComplete"] && ((SPPanelManager *)object).dataFetchComplete) {
        [object removeObserver:self forKeyPath:@"dataFetchComplete"];

        //Other stuff
    }
}

然后当我稍后离开 UIViewController 时，每个管理器对象都会出现以下错误:

An instance of class was deallocated while key value observers were still registered with it. Observation info was leaked, and may even become mistakenly attached to some other object.

我不确定为什么它会给我这个错误 - 这是唯一引用 KVO 的 2 个地方，所以它不是另一个观察者。

Answer 1

您的类(class)(观察者)正在某些事件期间被释放。您必须在它被解除分配或不再被进一步使用之前注销它。在 viewDidUnload: 或 dealloc:

中使用下面的代码

for (SPPanelManager *manager in self.panelManagers) {
    [manager removeObserver:self forKeyPath:@"dataFetchComplete" context:NULL];
  }