iphone - AVAudioPlayer isPlaying 始终返回 null

Question

我在 AVAudioPlayer 类中遇到了一个奇怪的问题。每次我尝试访问它的属性之一时，它们都是空的。

// Get the file path to the song to play.
 NSString *filePath = [[[NSBundle mainBundle] pathForResource:pSound.fileName 
               ofType:pSound.fileType] retain];

 // Convert the file path to a URL.
 NSURL *fileURL = [[NSURL alloc] initFileURLWithPath:filePath];

 NSError* err;
 //Initialize the AVAudioPlayer
 self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:fileURL error:&err];

    if( err ){
  NSLog(@"Initializing failed with reason: %@", [err localizedDescription]);
 }
 else{
  [self.audioPlayer setDelegate:self];
  [self.audioPlayer prepareToPlay];
  self.playCount = self.playCount + 1;
        NSLog(@"%@", [self.audioPlayer isPlaying]); //this displays null; also if I call it at a later time
 };

 [filePath release];
 [fileURL release];

有什么想法吗？

编辑:奇怪的是，当我将 isPlaying 保存到 bool 并打印 bool 时，我得到一个值...

Answer 1

NSLog(@"%@", [self.audioPlayer isPlaying]); 

%@ - 表示您要打印 [yourObject toString] 的结果因此，如果您想检查 [self.audioPlayer isPlaying] 返回的 bool 值 - 您应该使用 %d。

附:不要忘记调用 [audioPlayer play];;)