IOS拼接MP3，歌曲文件合成。

其实就是把MP3文件转成NSData，然后再进行拼合。

 - (void)viewDidLoad
 {
     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.

     //音频文件路径
     NSString *mp3Path1 = [[NSBundle mainBundle] pathForResource:@"1" ofType:@"mp3"];
     NSString *mp3Path2 = [[NSBundle mainBundle] pathForResource:@"2" ofType:@"mp3"];
     NSString *mp3Path3 = [[NSBundle mainBundle] pathForResource:@"3" ofType:@"mp3"];
     //音频数据
     NSData *sound1Data = [[NSData alloc] initWithContentsOfFile: mp3Path1];
     NSData *sound2Data = [[NSData alloc] initWithContentsOfFile: mp3Path2];
     NSData *sound3Data = [[NSData alloc] initWithContentsOfFile: mp3Path3];

     //合并音频
     NSMutableData *sounds = [NSMutableData alloc];
     [sounds appendData:sound1Data];
     [sounds appendData:sound2Data];
     [sounds appendData:sound3Data];
     //保存音频

     NSLog(@"data length:%d", [sounds length]);

     [sounds writeToFile:[self filePathWithName:@"tmp.mp3"] atomically:YES];


     player = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:[self filePathWithName:@"tmp.mp3"]] error:nil];
     player.delegate = self;
     [player prepareToPlay];
 }

 - (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
 {
     MPMusicPlayerController *ipodPlayer = [MPMusicPlayerController iPodMusicPlayer];
     if ([ipodPlayer playbackState] == MPMusicPlaybackStateInterrupted) {
         [ipodPlayer play];
     }
 }

 - (void)didReceiveMemoryWarning
 {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 - (NSString *)filePathWithName:(NSString *)filename
 {
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
     NSString *documentsDirectory = [paths objectAtIndex:0];
     return [documentsDirectory stringByAppendingPathComponent:filename];
 }


 - (IBAction)buttonClick:(id)sender {


     [player play];

 }