@interface AppDelegate (visibleVC)
// 获取当前展示的vc
- (UIViewController *)visibleViewController;

@end

@implementation AppDelegate (visibleVC)

- (UIViewController *)visibleViewController {
    UIViewController *rootViewController = self.window.rootViewController;
    return [self getVisibleViewControllerFrom:rootViewController];
}

-(UIViewController *) getVisibleViewControllerFrom:(UIViewController *) vc {
    if ([vc isKindOfClass:[UINavigationController class]]) {
        return [self getVisibleViewControllerFrom:[((UINavigationController *) vc) visibleViewController]];
    } else if ([vc isKindOfClass:[UITabBarController class]]) {
        return [self getVisibleViewControllerFrom:[((UITabBarController *) vc) selectedViewController]];
    } else {
        if (vc.presentedViewController) {
            return [self getVisibleViewControllerFrom:vc.presentedViewController];
        } else {
            return vc;
        }
    }
}

@end