ios 调节系统音量

-(void)setSystemVolummMax

{

    NSLog(@"volum=====%f", [[MPMusicPlayerController applicationMusicPlayer] volume]);

    if([[MPMusicPlayerController applicationMusicPlayer] volume] <1.0)

    {

        MPVolumeView *volumeView = [[MPVolumeView alloc] initWithFrame:CGRectMake(-1000.f,-1000, 10, 10)];

        [[UISlider appearanceWhenContainedIn:[MPVolumeView class], nil] setMinimumValueImage:[UIImage imageNamed:@"icon-volumeMin"]];

        [[UISlider appearanceWhenContainedIn:[MPVolumeView class], nil] setMaximumValueImage:[UIImage imageNamed:@"icon-volumeMax"]];

        volumeView.center = CGPointMake(-100, -100);

        volumeView.showsRouteButton = NO;

        volumeView.hidden = YES;

        UISlider *slider = nil;

        for (UIView *view in [volumeView subviews]){

            if ([view.class.description isEqualToString:@"MPVolumeSlider"]){

                slider = (UISlider*)view;

                break;

            }

        }

        // NSLog(@"当前系统音量是:%.2f",slider.value);

        slider.value = 1.0;

        slider.hidden = YES;

        [self.view addSubview:volumeView];

        [volumeView sendSubviewToBack:self.view];// 不显示系统音量图标

    }

}