播放聲音文件iOS

Question

我正在viewDidLoad方法中播放聲音文件。 聲音文件保存在文檔目錄中。 首次加載視圖時成功播放。 但是，當我彈出該視圖並返回時，它不會播放。

這是我的代碼：

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *localFilePathSound =[[NSString alloc] initWithString:[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"sound.caf"]]];

    if ([[NSFileManager defaultManager] fileExistsAtPath:localFilePathSound]) {
        //NSString *clapPath = [[NSBundle mainBundle] pathForResource:@"scaryVoice" ofType:@"wav"];
        CFURLRef clapURL = (CFURLRef ) [NSURL fileURLWithPath:localFilePathSound];
        AudioServicesCreateSystemSoundID (clapURL, &clappingFileId);
        AudioServicesPlaySystemSound(clappingFileId);
    }
    // Do any additional setup after loading the view from its nib.
    else{
        NSString *clapPath = [[NSBundle mainBundle] pathForResource:@"scaryVoice" ofType:@"wav"];
        CFURLRef clapURL = (CFURLRef ) [NSURL fileURLWithPath:clapPath];
        AudioServicesCreateSystemSoundID (clapURL, &clappingFileId);
        AudioServicesPlaySystemSound(clappingFileId);
    }
}

Answer 1

從視圖返回后是否要播放此方法。 只需在- (void)viewWillAppear:(BOOL)animated 或 - (void)viewDidAppear:(BOOL)animated方法中編寫以上代碼。

- (void)viewWillAppear:(BOOL)animated
{
   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *localFilePathSound =[[NSString alloc] initWithString:[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"sound.caf"]]];

    if ([[NSFileManager defaultManager] fileExistsAtPath:localFilePathSound])
    {
        //NSString *clapPath = [[NSBundle mainBundle] pathForResource:@"scaryVoice" ofType:@"wav"];
        CFURLRef clapURL = (CFURLRef ) [NSURL fileURLWithPath:localFilePathSound];
        AudioServicesCreateSystemSoundID (clapURL, &clappingFileId);
        AudioServicesPlaySystemSound(clappingFileId);
    }
    // Do any additional setup after loading the view from its nib.
    else
    {
        NSString *clapPath = [[NSBundle mainBundle] pathForResource:@"scaryVoice" ofType:@"wav"];
        CFURLRef clapURL = (CFURLRef ) [NSURL fileURLWithPath:clapPath];
        AudioServicesCreateSystemSoundID (clapURL, &clappingFileId);
        AudioServicesPlaySystemSound(clappingFileId);
    }
}

Answer 2

您的viewDidLoad方法僅在視圖第一次出現時被調用。 為了使每次視圖出現時都能發生某些事情，請將您的代碼放入viewWillAppear: 。

確保從您的方法中調用[super viewWillAppear:animated] 。