简单的音乐播放 导入AVFoundation.framework

- (void)viewDidLoad  {      [super viewDidLoad];         //路径      NSString* path = [[NSBundle mainBundle] pathForResource:@"xiguan" ofType:@"mp3"];      //路径->url      NSURL* url = [NSURL fileURLWithPath:path];             _player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];      //准备播放      [_player prepareToPlay];      //支持变速      _player.enableRate = YES;      //峰值 平均值      _player.meteringEnabled = YES;  }     //进度  - (IBAction)proSlider:(id)sender{      //当前时间=总时间*slider.value;      float currentTime = _player.duration * _proSlider.value;      [_player setCurrentTime:currentTime];  }  //声道  - (IBAction)panSlider:(id)sender{      _player.pan = _panSlider.value;  }  //速度  - (IBAction)speedSlider:(id)sender{      _player.rate = _speedSlider.value;  }  //声音  - (IBAction)volSlier:(id)sender{      _player.volume = _volSlider.value;  }        - (void)play:(id)sender{      [_player play];      //播放时候开启定时器      _timer = [NSTimer scheduledTimerWithTimeInterval:1/60.0 target:self selector:@selector(refresh) userInfo:nil repeats:YES];  }     - (void)pause:(id)sender{      [_player pause];      //暂定的时候定时器失效      [_timer invalidate];  }     - (void)refresh{      //当前时间/总时间      float pro = _player.currentTime / _player.duration;      [_proSlider setValue:pro animated:YES];             //刷新峰值平均值      [_player updateMeters];      float peak = ([_player peakPowerForChannel:0] + 50) / 50;      float ave = ([_player averagePowerForChannel:0] + 50) / 50;      [_proV setProgress:peak animated:YES];      [_proV2 setProgress:ave animated:YES];  }        /////播放系统声音     SystemSoundID myAlertSound;          NSURL *url = [NSURL URLWithString:@"/System/Library/Audio/UISounds/alarm.caf"];          /*           low_power.caf  alarm.caf  SentMessage.caf           */          AudioServicesCreateSystemSoundID((__bridge CFURLRef)(url), &myAlertSound);          AudioServicesPlaySystemSound(myAlertSound);