AVFoundation - iOS听不到声音

Question

我正在尝试使用AVFoundation框架播放一个mp3文件。它无法检测到该文件，并出现以下错误：

     Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSURL initFileURLWithPath:]: nil string parameter'

已实现的代码：

NSString *path = [[NSBundle mainBundle] pathForResource:@"sound" ofType:@"mp3"];
NSLog(@"directory %@",path);
AVAudioPlayer* theAudio = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:NULL];
theAudio.delegate = self;
[theAudio play];

当我将pathForResource：@“声音”更改为pathForResource：@“声音”(空格)时，它可以检测到文件，但听不到声音。我也在.h文件中声明了AVdelegate。有人知道问题出在哪里吗？

Answer 1

您需要先使用gige prepareToPlay才能播放音频。检查此代码片段..这对我很管用。

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory，NSUserDomainMask，是)；

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *filePath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.mp3", fileName]];

NSError        *err;

if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) 
{    
    AVAudioPlayer  *player = [[AVAudioPlayer alloc] initWithContentsOfURL:
              [NSURL fileURLWithPath:filePath] error:&err];

    player.delegate = self;

    [player prepareToPlay];
    [player setNumberOfLoops:0];
    [player setVolume:0.5];
    [player play];    

}