iOS開發——獲取當前屏幕顯示的viewcontroller

　　獲取當前屏幕顯示的viewcontroller，然后想怎么跳就怎么跳。

- (UIViewController *)getCurrentVC

{

    UIViewController *result = nil;

    

    UIWindow * window = [[UIApplication sharedApplication] keyWindow];

    if (window.windowLevel != UIWindowLevelNormal)

    {

        NSArray *windows = [[UIApplication sharedApplication] windows];

        for(UIWindow * tmpWin in windows)

        {

            if (tmpWin.windowLevel == UIWindowLevelNormal)

            {

                window = tmpWin;

                break;

            }

        }

    }

    

    UIView *frontView = [[window subviews] objectAtIndex:0];

    id nextResponder = [frontView nextResponder];

    

    if ([nextResponder isKindOfClass:[UIViewController class]])

        result = nextResponder;

    else

        result = window.rootViewController;

    

    return result;

}