iOS开发之获取当前栈中的控制器

-(UIViewController *)currentViewController{
    
    UIViewController * currVC = nil;
    UIViewController * Rootvc = keyWindow.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;
        }
    } while (Rootvc!=nil);
    
    return currVC;
}