Obtains the Controller currently displayed in the window.

Obtains the Controller currently displayed in the window.

This solution is similar to the requirement that the Netease news client should pop up a UIAlert after receiving the News Push and jump to the news details page.

1. Provides a classification method for UIView. This method obtains the controller of the view through the responder chain.

- (UIViewController *)parentController{    UIResponder *responder = [self nextResponder];    while (responder) {        if ([responder isKindOfClass:[UIViewController class]]) {            return (UIViewController *)responder;        }        responder = [responder nextResponder];    }    return nil;}

2. The controller instance object can be obtained through the Layout View of the controller.

Modal display mode requires the Controller's Root View

+ (UIViewController *) currentViewController {UIWindow * keyWindow = [UIApplication sharedApplication]. keyWindow; // The underlying view of the modal display mode is different // when the first layer is obtained, the UITransitionView is obtained, and the Controller UIView * firstView = [keyWindow. subviews firstObject]; UIView * secondView = [firstView. subviews firstObject]; UIViewController * vc = secondView. parentController; if ([vc isKindOfClass: [UITabBarController class]) {UITabBarController * tab = (UITabBarController *) vc; if ([tab. selectedViewController isKindOfClass: [UINavigationController class]) {UINavigationController * nav = (UINavigationController *) tab. selectedViewController; return [nav. viewControllers lastObject];} else {return tab. selectedViewController;} else if ([vc isKindOfClass: [UINavigationController class]) {UINavigationController * nav = (UINavigationController *) vc; return [nav. viewControllers lastObject];} else {return vc;} return nil ;}