presentedViewController 导致alert无法正常显示

//小心下面这个问题
[self presentViewController:self completion:nil];

//获取当前屏幕显示的Presented 出来的viewcontroller
+ (UIViewController *)getPresentedViewController
{
    UIViewController *appRootVC = [UIApplication sharedApplication].keyWindow.rootViewController;
    UIViewController *topVC = appRootVC;
    while (topVC.presentedViewController) {
        if ([[topVC.presentedViewController class] isSubclassOfClass:[UINavigationController class]]) {
            topVC = ((UINavigationController *)topVC.presentedViewController).viewControllers.lastObject;
        }else{
            topVC = topVC.presentedViewController;
        }
    }
    return topVC;
}

//用getPresentedViewController解决
    [KapHudManager.rootViewController presentViewController:alert animated:YES completion:nil];