ios appdelegate中获取当前显示页

ios appdelegate中获取当前显示页

网上有很多种方法，但是都不好使，找到了这个好使的，和大家分享下。

-(UIViewController *)currentViewController
{
    UIViewController * currVC = nil;
    UIViewController * Rootvc = self.window.rootViewController ;
    do {
        if ([Rootvc isKindOfClass:[UINavigationController class]]) {
            UINavigationController * nav = (UINavigationController *)Rootvc;
            UIViewController * v = [nav.viewControllers lastObject];
            currVC = v;
            Rootvc = v.presentedViewController;
            continue;
        }else if([Rootvc isKindOfClass:[UITabBarController class]]){
            UITabBarController * tabVC = (UITabBarController *)Rootvc;
            currVC = tabVC;
            Rootvc = [tabVC.viewControllers objectAtIndex:tabVC.selectedIndex];
            continue;
        }
//        else if ([Rootvc isKindOfClass:[XXXCustom class]]){
//            XXXCustom * tabVC = (XXXCustom *)Rootvc;
//            currVC = tabVC;
//            Rootvc = tabVC.selectedViewController;
//            continue;
//        }
    } while (Rootvc!=nil);
    
    
    return currVC;
}