viewDidUnload - 在視圖更改時停止方法

Question

我正在尋找在視圖更改時停止播放音頻文件。

我正在使用tabController，我希望當用戶移動到不同的視圖時播放的音頻停止。我不確定我會在哪裏以及如何做到這一點。在viewDidUnload也許？

這裏是我用來播放音頻文件的方法：

- （無效）{startPlaying [的NSTimer scheduledTimerWithTimeInterval：15目標：自我選擇：@selector（startPlaying）USERINFO：無重複：NO] ; NSString * audioSoundPath = [[NSBundle mainBundle] pathForResource：@「audio_file」ofType：@「caf」]; CFURLRef audioURL =（CFURLRef）[NSURL fileURLWithPath：audioSoundPath]; AudioServicesCreateSystemSoundID（audioURL，& audioID）; AudioServicesPlaySystemSound（audioID）; }

感謝您的幫助

Answer 1

像這樣的事情在您的視圖控制器（未經測試）：

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    // Load sample 
    NSString *audioSoundPath = [[NSBundle mainBundle] pathForResource:@"audio_file" 
                   ofType:@"caf"]; 
    CFURLRef audioURL = (CFURLRef)[NSURL fileURLWithPath:audioSoundPath]; 
    AudioServicesCreateSystemSoundID(audioURL, &audioID) 
} 

- (void)viewDidUnload 
{ 
    // Dispose sample when view is unloaded 
    AudioServicesDisposeSystemSoundID(audioID); 

    [super viewDidUnload]; 
} 

// Lets play when view is visible (could also be changed to viewWillAppear:) 
- (void)viewDidAppear:(BOOL)animated 
{ 
    [super viewDidAppear:animated]; 

    [self startPlaying]; 
} 

// Stop audio when view is gone (could also be changed to viewDidDisappear:) 
- (void)viewWillDisappear:(BOOL)animated 
{ 
    [super viewWillDisappear:animated]; 

    if([self.audioTimer isValid]) { 
     [self.audioTimer invalidate]; 
    } 
    self.timer = nil; 
} 

// Start playing sound and reschedule in 15 seconds. 
-(void)startPlaying 
{ 
    self.audioTimer = [NSTimer scheduledTimerWithTimeInterval:15 target:self 
                selector:@selector(startPlaying) 
                userInfo:nil 
                 repeats:NO]; 
    AudioServicesPlaySystemSound(audioID); 
} 

缺少：

• 錯誤檢查
• 物業或伊娃的audioTimer 。
• 也可以保持相同的計時器，重複YES。
• 釋放dealloc中的資源。
• 測試