ios - IOS的AudioToolBox出现EXC_BAD_ACCESS如何解决

Question

我需要帮助解决在 MPMoviePlayerController 和 MPMusicPlayerController 之间转换期间 AudioToolBox (AVAudioSessionPropertyListener) 中偶尔发生 EXC_BAD_ACCESS 崩溃的问题。以下是调用轨迹:

OS Version:      iPhone OS 5.1 (9B176)
Report Version:  104

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x00000009
Crashed Thread:  0

Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libobjc.A.dylib                 0x3676ef78 objc_msgSend + 16
1   AVFoundation                    0x31e60b1c _ZL30AVAudioSessionPropertyListenerPvmmPKv + 236
2   AudioToolbox                    0x3630b300 AudioSessionPropertyListeners::CallPropertyListenersImp(unsigned long, unsigned long, void const*) + 268
3   AudioToolbox                    0x3630b5de AudioSessionPropertyListeners::CallPropertyListeners(unsigned long, unsigned long, void const*) + 234
4   AudioToolbox                    0x3630925a SSServer_AudioSessionInterruptionListenerMessage + 50
5   AudioToolbox                    0x362b0d2c _XAudioSessionInterruptionListenerMessage + 56
6   AudioToolbox                    0x36245cdc mshMIGPerform + 368
7   CoreFoundation                  0x3532151c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 32
8   CoreFoundation                  0x353214be __CFRunLoopDoSource1 + 134
9   CoreFoundation                  0x3532030c __CFRunLoopRun + 1364
10  CoreFoundation                  0x352a349e CFRunLoopRunSpecific + 294
11  CoreFoundation                  0x352a3366 CFRunLoopRunInMode + 98
12  GraphicsServices                0x3659f432 GSEventRunModal + 130
13  UIKit                           0x32399e76 UIApplicationMain + 1074
14  MyGreatApp                      0x00054986 main (main.m:14)
15  MyGreatApp                      0x00054944 start + 32

我的应用交替使用音乐播放器和电影播放器​​。电影播放器​​用于播放播客。每次播放新播客时，电影播放器​​都会分配一个自动释放。当我用完电影播放器​​后，我会删除我设置的所有观察者，确保电影播放器​​已停止，然后重新启动音乐播放器。

下面是一些初始化电影播放器​​使用的相关代码:

[musicPlayer pause];

self.moviePlayer = [[[MPMoviePlayerController alloc] initWithContentURL: address] autorelease];   // Release the old moviePlayer and create a new one.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePreloadDidFinish:) name:MPMoviePlayerLoadStateDidChangeNotification object:self.moviePlayer];    

// Register to receive a notification when the movie has finished playing. 
[[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(moviePlayBackDidFinish:) name:MPMoviePlayerPlaybackDidFinishNotification object:self.moviePlayer];

// Register to receive a notification when the movie playback state changes (specifically looking for the state of interrupted). 
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayBackStateChanged:) name:MPMoviePlayerPlaybackStateDidChangeNotification object:self.moviePlayer];

[self.moviePlayer play];

电影可以在播放完后结束，或者用户可以通过按快进按钮终止电影。下面是处理这两种情况的相关代码:

-(IBAction) fastForwardMovie: (id) sender {

        // The self.moviePlayer is still playing, but the user wants to skip the rest of the movie/podcast. 
        // Lets fake a movie playback did finish event
        NSNotification *notification = [NSNotification notificationWithName:MPMoviePlayerPlaybackDidFinishNotification object:nil];
        [self moviePlayBackDidFinish: notification];    // Fake a finished playback so that the music player can be restarted
        return;
}


//  Notification called when the movie FINISHED playing.
- (void) moviePlayBackDidFinish:(NSNotification*)notification { 
    // Remove further notifications until the next time we need the movie player
    [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerLoadStateDidChangeNotification object:self.moviePlayer] ;
    [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackDidFinishNotification object:self.moviePlayer] ;
    [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackStateDidChangeNotification object:self.moviePlayer] ;


    // Get rid of the movie player
    self.moviePlayer.initialPlaybackTime = -1;  // seems that the best way to kill the movie player is first setting the playback time to -1
    [self.moviePlayer stop];                    // followed by stopping the player

    [musicPlayer play];
}

电影(播客)结束后，即使发生崩溃(但应用程序已终止)，音乐也会播放。这是因为我使用的是 iPod 音乐播放器，但这可能表明问题与电影播放器​​有关。

最后一点。我已尝试仔细遵循 Apple 的 Audio Session Programming Guide 指南，其中指出当所需配置是混合所有音频时，您应该“使用可混合类别配置配置 Audio Session ”和“利用电影播放器的默认 useApplicationAudioSession 值为 YES。

谁能帮我弄清楚我可能做错了什么导致 AVAudioSessionPropertyListener 因 EXC_BAD_ACCESS 而崩溃？或者至少你能给我一个建议，告诉我如何隔离这个问题以确定根本原因吗？

Answer 1

尝试调用 [musicPlayer performSelectorOnMainThread:@selector(play) ...] 吗？