在 iPhone 应用程序中使用 AVSystemController

我想以编程方式降低iPhone的铃声音量，我发现可以用AVSystemController，但我知道，它是一个私有方法。如果我使用它，苹果会拒绝该应用程序还是请建议我其他方式

- (void) setSystemVolumeLevelTo:(float)newVolumeLevel
{
    Class avSystemControllerClass = NSClassFromString(@"AVSystemController");
    id avSystemControllerInstance = [avSystemControllerClass performSelector:@selector(sharedAVSystemController)];

    NSString *soundCategory = @"Ringtone";

    NSInvocation *volumeInvocation = [NSInvocation invocationWithMethodSignature:
                                  [avSystemControllerClass instanceMethodSignatureForSelector:
                                   @selector(setVolumeTo:forCategory:)]];
    [volumeInvocation setTarget:avSystemControllerInstance];
    [volumeInvocation setSelector:@selector(setVolumeTo:forCategory:)];
    [volumeInvocation setArgument:&newVolumeLevel atIndex:2];
    [volumeInvocation setArgument:&soundCategory atIndex:3];
    [volumeInvocation invoke];
}