iOS 修改系统的音量

#import 
 



@property (strong, nonatomic) MPVolumeView *volumeView;
@property (strong, nonatomic) UISlider *volumeViewSlider;



- (void)viewDidLoad {
	if (!self.volumeView) {
        
       self.volumeView = [[MPVolumeView alloc] initWithFrame:CGRectMake(-1000, -100, 100, 100)];
       
       for (UIView *view in [self.volumeView subviews]) {
           if ([view.class.description isEqualToString:@"MPVolumeSlider"]) {
               self.volumeViewSlider = (UISlider *)view;
               break;
           }
       }
    }
                      
   [self.volumeView setFrame:CGRectMake(16, 100, [UIScreen mainScreen].bounds.size.width - 32, 20)];
   [self.view addSubview:self.volumeView];

	
}

   // 静音操作
        [self.volumeViewSlider setValue:SoundVolume animated:YES];