当AVPlayer在被释放之后,Player一直监听的时间没有被移除,提示错误的解决办法

Xcode Consolu打印出来的提示：

An instance 0x156608c0 of class AVPlayer 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. Set a breakpoint on NSKVODeallocateBreak to stop here in the debugger. Here's the current observation info:

<NSKeyValueObservationInfo 0x15634320> (

<NSKeyValueObservance 0x15597fa0: Observer: 0x15674660, Key path: currentItem, Options: <New: YES, Old: NO, Prior: NO> Context: 0x134cc4, Property: 0x1558ff20>

<NSKeyValueObservance 0x15598da0: Observer: 0x15674660, Key path: rate, Options: <New: YES, Old: NO, Prior: NO> Context: 0x134cc0, Property: 0x1559ad40>

提示的说明了AVPlayer这个类已经被释放了,当已经登记了消息监听还登记着,这可能会引起消息的泄漏,我的解决办法是在移除视图之前取消监听时间.

AVPlayer的监听部分代码:

  [self setPlayer:[AVPlayer playerWithPlayerItem:self.playerItem]];

        /* Observe the AVPlayer "currentItem" property to find out when any
         AVPlayer replaceCurrentItemWithPlayerItem: replacement will/did
         occur.*/
        [self.player addObserver:self
                      forKeyPath:kCurrentItemKey
                         options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
                         context:AVARLDelegateDemoViewControllerCurrentItemObservationContext];

        /* Observe the AVPlayer "rate" property to update the scrubber control. */
        [self.player addObserver:self
                      forKeyPath:kRateKey　　　　
                         options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
                         context:AVARLDelegateDemoViewControllerRateObservationContext];

 [self.playerItem addObserver:self
　　
　　　　　　　　　　　　　　forKeyPath:kStatusKey

　　　　　　　　　　　　　　　　options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew

                          context:AVARLDelegateDemoViewControllerStatusObservationContext];

解决办法：

- (void)viewWillDisappear:(BOOL)animated{
    NSLog(@"Disappear");
　　if(self.playerItem && self.player){

　　　　[self.playerItem removeObserver:self forKeyPath:kStatusKey context:AVARLDelegateDemoViewControllerStatusObservationContext];
　　　　
  　　 [self.player removeObserver:self forKeyPath:kRateKey context:AVARLDelegateDemoViewControllerRateObservationContext];

    　[self.player removeObserver:self forKeyPath:kCurrentItemKey context:AVARLDelegateDemoViewControllerCurrentItemObservationContext];
}