//獲得當前屏幕亮度  light = [UIScreen mainScreen].brightness;  light = 0.5f;  //直接賦值或者使用set方法皆可  [UIScreen mainScreen].brightness = light;

MPMusicPlayerController *mpVC = [MPMusicPlayerController applicationMusicPlayer];//獲得系統當前音量voice = _mpVC.volume;voice = 0.5f;//改變系統音量_mpVC.volume = voice;

- (void)leftSwipGes:(UIPanGestureRecognizer *)leftSwip{  //滑動方法獲取到當前位置的y坐標  leftCurrentY = [leftSwip translationInView:leftView].y;  NSLog(@"left");  //當前坐標大于上一次移動的坐標，為向下滑動  if (leftCurrentY > leftLastY) {    if (light > 0) {      //向下滑動屏幕變暗，亮度下降      light = light - 0.01;    }    else{      //當亮度為0時固定為0，禁止為負值      light = 0;    }  }  else  {    if (light < 1) {      //向上滑動亮度增加      light = light + 0.01;    }    else{      //當亮度為1時固定為1，禁止大于1      light = 1;    }  }  //設置屏幕亮度  [UIScreen mainScreen].brightness = light;  //當前位置的上一次移動的位置y坐標  leftLastY = leftCurrentY;}//此處除參數外原理一樣，不再額外注釋- (void)rightSwipGes:(UIPanGestureRecognizer *)rightSwip{  NSLog(@"right");  rightCurrentY = [rightSwip translationInView:rightView].y;  if (rightCurrentY > rightLastY) {    if (voice > 0) {      voice = voice - 0.01;    }    else{      voice = 0;    }  }  else  {    if (voice < 1) {      voice = voice + 0.01;    }    else{      voice = 1;    }  }  //設置系統音量  _mpVC.volume = voice;  rightLastY = rightCurrentY;}

//從budle路徑下讀取音頻文件,這個文件名是你的歌曲名字,mp3是你的音頻格式  NSString *string = [[NSBundle mainBundle] pathForResource:@"夜空中最亮的星" ofType:@"mp3"];  NSString *playUrl = [string stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; //轉碼成UTF-8 否則可能會出現錯誤  //把音頻文件轉換成url格式  NSURL *url = [NSURL URLWithString:playUrl];  //初始化音頻類 并且添加播放文件  _avAudioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];  [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];  //設置初始音量大小  _avAudioPlayer.volume = voice;  //設置音樂播放次數 -1為一直循環  _avAudioPlayer.numberOfLoops = -1;  //預播放  [_avAudioPlayer prepareToPlay];  [_avAudioPlayer play];

 [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];