Get Viewcontroller that is currently active in iOS apps

Gets the currently active view controller-(Uiviewcontroller *) activityviewcontroller{uiviewcontroller*        Activityviewcontroller = 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    }}} Nsarray *viewsarray = [window subviews];                if ([Viewsarray count] > 0) {UIView *frontview = [Viewsarray objectatindex:0];                ID nextresponder = [frontview Nextresponder];        if ([Nextresponder Iskindofclass:[uiviewcontroller class]]) {activityviewcontroller = Nextresponder;        } else {activityviewcontroller = Window.rootviewcontroller; }} return ActivityvieWcontroller;} 

Get Viewcontroller that is currently active in iOS apps