按主頁按鈕后，iPhone應用程序中沒有聲音

Question

我的聲音在模擬器中運行正常，但是當我在手機上運行應用程序時，按下主頁按鈕然后返回應用程序后聲音停止工作。 這是在IOS5中。 我怎么解決這個問題？ AVAudioPlayer的委托事情似乎也停止了。 該應用程序不會崩潰。

NSString *path = [[NSBundle mainBundle]
    pathForResource:@"Beep01" ofType:@"wav"];
clickSound =[[AVAudioPlayer alloc] initWithContentsOfURL:
    [NSURL fileURLWithPath:path] error:NULL];
clickSound.delegate = self;
[clickSound prepareToPlay];

后來我用[clickSound play]播放它;

Answer 1

確保你有

#import <AVFoundation/AVFoundation.h>

在你的標題中。 然后在你的AppDelegate中你應該有這個方法：

- (AVAudioPlayer *) getSound: (NSString *) soundName {  
@try {              
    AVAudioPlayer *sound = [[self getDictionary] objectForKey: soundName];      
    if (!sound) {           
        NSError *error;
        NSString *path = [[NSBundle mainBundle] pathForResource: soundName ofType: nil];             
        sound = [[AVAudioPlayer alloc] initWithContentsOfURL: [NSURL fileURLWithPath: path] 
                                                       error: &error];             
        if (!sound) {
            //NSLog(@"ERROR: Wrong sound format: %@. Description: %@",  soundName,  [error localizedDescription]);
        } else {
            sound.volume = 0.7;
            //int len = sound.duration;
            [[self getDictionary] setObject: sound forKey: soundName];
            // NSLog(@"%@ loaded, duration: %i sec", soundName, len);
            [sound release];
        }    
    } 
    return sound;
} 
@catch (id theException) {
    NSLog(@"ERROR: %@ not found!", soundName);
} 
return nil;

}

- (NSMutableDictionary *) getDictionary {
if (!dictionary) { //Hashtable
    dictionary = [[NSMutableDictionary alloc] init]; 
    NSLog(@"new Dictionary");
}
return dictionary;
}
- (void) playSound: (NSString *) soundName {
AVAudioPlayer *sound = [self getSound: soundName];
if (sound) {   
    sound.currentTime = 0;        
    if (!sound.playing) {
        sound.numberOfLoops = 0;
        [sound play];
    }    
} 
}

- (void) stopSound: (NSString *) soundName {
AVAudioPlayer *sound = [self getSound: soundName];
if (sound && sound.playing) {           
    [sound stop];         
} 
}

在你的AppDelegateDidFinishLaunching中你預先加載你將使用的所有聲音：

//pre-Load sounds
[self getSound: @"testSong.wav"];

在你的 - （void）play {}方法中

    YourAppDel *appDel = [UIApplication sharedApplication].delegate;
    [appDel playSound:@"testSong.wav"];

enjoi

Answer 2

當您的應用程序轉到后台（或時鍾鬧鍾響起，或手機接到電話或屏幕鎖定）時，應用程序的音頻會話中斷，您的音頻播放器暫停。 處理此中斷的推薦方法是在音頻播放器的委托中實現AVAudioPlayerDelegate方法– audioPlayerBeginInterruption:和-audioPlayerEndInterruption: 來自Apple的文檔 ：

- (void)audioPlayerBeginInterruption:(AVAudioPlayer *)player {
    if (playing) {
        playing = NO;
        interruptedOnPlayback = YES;
        [self updateUserInterface];
    }
}

- (void)audioPlayerEndInterruption:(AVAudioPlayer *)player {
    if (interruptedOnPlayback) {
        [player prepareToPlay];
        [player play];
        playing = YES;
        interruptedOnPlayback = NO;
    }
}

請注意，當-audioPlayerEndInterruption:時，會再次將-prepareToPlay發送到音頻播放器實例。 如果您在中斷后沒有調用它，那么您的音頻會話可能不會重新啟動，這將產生您上面描述的效果 - 神秘的死音頻。