Ios5 AVPlayer observeValueForKeyPath_Ios5_Audio Streaming_Avplayer_Avaudiosession_Addobserver

Ios5 AVPlayer observeValueForKeyPath

ios5

Ios5 AVPlayer observeValueForKeyPath,ios5,audio-streaming,avplayer,avaudiosession,addobserver,Ios5,Audio Streaming,Avplayer,Avaudiosession,Addobserver,我有一个播放流内容的音频应用程序。问题是有时，当信号弱时，它停止播放。网络仍然可以访问，但缓冲区似乎已空运行我尝试实现一个观察器来监视玩家的状态变化，但它不起作用，该方法从未被调用作为一种特殊性，AVPlayer实例位于AppDelegate中，因为我有多个视图，播放器必须继续播放显示的任何视图。下面是一段示例代码： - (void)viewDidLoad { [super viewDidLoad]; isPlaying = false;

我有一个播放流内容的音频应用程序。问题是有时，当信号弱时，它停止播放。网络仍然可以访问，但缓冲区似乎已空运行

我尝试实现一个观察器来监视玩家的状态变化，但它不起作用，该方法从未被调用

作为一种特殊性，AVPlayer实例位于AppDelegate中，因为我有多个视图，播放器必须继续播放显示的任何视图。下面是一段示例代码：

- (void)viewDidLoad
    {
        [super viewDidLoad];
        isPlaying = false;
        playButton.enabled = NO;

        //Add en observer for reachability change
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(reachabilityChanged:) 
                                                     name:kReachabilityChangedNotification
                                                   object:nil];

        //Adding the observer for player's status change
        AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
        [delegate.player addObserver:self forKeyPath:@"status" options:0 context:playerStatusContext];

        [self initPlayer];
    }


    //Event raised whenever the current status of the player change
    - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

        UIAlertView *alert = [UIAlertView alloc];
        NSString *chaineConcat = @"Entering observer method..."];
        [alert initWithTitle:@"Test" message:chaineConcat delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];   
        [alert show];

        if (context == playerStatusContext) {
            AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
            NSString *statusPlayer = nil; 
            if (object == delegate.player && [keyPath isEqualToString:@"status"]) {
                if (delegate.player.status == AVPlayerStatusReadyToPlay) {
                    statusPlayer = @"Everything's OK";
                } else if (delegate.player.status == AVPlayerStatusFailed) {
                    statusPlayer = @"Houston, we have a problem";
                }
            }
            [self syncUI];

            UIAlertView *alert = [UIAlertView alloc];
            NSString *chaineConcat = [NSString stringWithFormat:@"%@/%@/", @"Player status' is ", statusPlayer];
            [alert initWithTitle:@"Test" message:chaineConcat delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];   
            [alert show];

        }else {
            [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
        }

        return;
    }

- (void) initPlayer {

    // Load the array with the sample file
    NSString *urlAddress = @"http://MYSTREAMURL";

    AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

    //Create a URL object.
    delegate.urlStream = [NSURL URLWithString:urlAddress];

    //Reinit AVPlayer
    delegate.player = [AVPlayer playerWithURL:delegate.urlStream];

}

有没有人知道为什么不举办这个活动？我在方法中有2个警报，但没有人被触发，这意味着它没有进入方法。所有这一切的目标都是试图实现一种方法，让玩家在这种情况下控制它

谢谢

您试图在创建要观察的对象之前添加观察者。您只是在向

nil

对象发送消息。

在调用之前调用

-initPlayer

-addObserver:forKeyPath:options:context:

您试图在创建要观察的对象之前添加观察者。您只是在向

nil

对象发送消息。

在调用之前调用

-initPlayer

-addObserver:forKeyPath:options:context:

以下是有效的代码

要声明可观察的AVPlayer对象，请执行以下操作：

@interface APLViewController ()
{
    AVPlayer *_player;
}

要分配和初始化AVPlayer，请执行以下操作：

- (void)viewDidLoad
{
[super viewDidLoad];

 _player = [[AVPlayer alloc] init];
}

添加观察员：

- (void)viewWillAppear:(BOOL)animated
{
    [self addObserver:self forKeyPath:@"player.currentItem.status" options:NSKeyValueObservingOptionNew context:AVPlayerItemStatusContext];
    [self addTimeObserverToPlayer];

    [super viewWillAppear:animated];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if (context == AVPlayerItemStatusContext) {
        AVPlayerStatus status = [change[NSKeyValueChangeNewKey] integerValue];
        switch (status) {
            case AVPlayerItemStatusUnknown:
                break;
            case AVPlayerItemStatusReadyToPlay:
                self.playerView.presentationRect = [[_player currentItem] presentationSize];
                break;
            case AVPlayerItemStatusFailed:
                [self stopLoadingAnimationAndHandleError:[[_player currentItem] error]];
                break;
        }
    }
    else {
        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    }
}

- (void)viewWillDisappear:(BOOL)animated
{
    [self removeObserver:self forKeyPath:@"player.currentItem.status" context:AVPlayerItemStatusContext];
    [self removeTimeObserverFromPlayer];

    [super viewWillDisappear:animated];
}

要处理观察者：

- (void)viewWillAppear:(BOOL)animated
{
    [self addObserver:self forKeyPath:@"player.currentItem.status" options:NSKeyValueObservingOptionNew context:AVPlayerItemStatusContext];
    [self addTimeObserverToPlayer];

    [super viewWillAppear:animated];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if (context == AVPlayerItemStatusContext) {
        AVPlayerStatus status = [change[NSKeyValueChangeNewKey] integerValue];
        switch (status) {
            case AVPlayerItemStatusUnknown:
                break;
            case AVPlayerItemStatusReadyToPlay:
                self.playerView.presentationRect = [[_player currentItem] presentationSize];
                break;
            case AVPlayerItemStatusFailed:
                [self stopLoadingAnimationAndHandleError:[[_player currentItem] error]];
                break;
        }
    }
    else {
        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    }
}

- (void)viewWillDisappear:(BOOL)animated
{
    [self removeObserver:self forKeyPath:@"player.currentItem.status" context:AVPlayerItemStatusContext];
    [self removeTimeObserverFromPlayer];

    [super viewWillDisappear:animated];
}

要删除观察员，请执行以下操作：

- (void)viewWillAppear:(BOOL)animated
{
    [self addObserver:self forKeyPath:@"player.currentItem.status" options:NSKeyValueObservingOptionNew context:AVPlayerItemStatusContext];
    [self addTimeObserverToPlayer];

    [super viewWillAppear:animated];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if (context == AVPlayerItemStatusContext) {
        AVPlayerStatus status = [change[NSKeyValueChangeNewKey] integerValue];
        switch (status) {
            case AVPlayerItemStatusUnknown:
                break;
            case AVPlayerItemStatusReadyToPlay:
                self.playerView.presentationRect = [[_player currentItem] presentationSize];
                break;
            case AVPlayerItemStatusFailed:
                [self stopLoadingAnimationAndHandleError:[[_player currentItem] error]];
                break;
        }
    }
    else {
        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    }
}

- (void)viewWillDisappear:(BOOL)animated
{
    [self removeObserver:self forKeyPath:@"player.currentItem.status" context:AVPlayerItemStatusContext];
    [self removeTimeObserverFromPlayer];

    [super viewWillDisappear:animated];
}

一定要把所有东西都放在我做过的地方，否则它可能不起作用。