iOS 修改手机系统音量

-(void)setIphoneVolume{

//iOS 7.0之前
// MPMusicPlayerController* musicController = [MPMusicPlayerController applicationMusicPlayer];
// musicController.volume = 1;

之后

MPVolumeView *volumeView = [[MPVolumeView alloc] init];
        UISlider* volumeViewSlider = nil;
        for (UIView *view in [volumeView subviews]){
            if ([view.class.description isEqualToString:@"MPVolumeSlider"]){
                volumeViewSlider = (UISlider*)view;
                break;
            }
        }
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.01 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[volumeViewSlider setValue:1 animated:YES];  0最小 1最大
[volumeViewSlider sendActionsForControlEvents:UIControlEventTouchUpInside];
});

}