iOS 获取当前的ViewController的方法

if ([nextResponder isKindOfClass:[UIViewController class]]) {    result = nextResponder;}else {    result = window.rootViewController;}

+ (UIViewController *)getCurrentViewController {  UIViewController *result = nil;  UIWindow * window = [[UIApplication sharedApplication] keyWindow];  //app默认windowLevel是UIWindowLevelNormal，如果不是，找到它  if (window.windowLevel != UIWindowLevelNormal) {    NSArray *windows = [[UIApplication sharedApplication] windows];    for(UIWindow * tmpWin in windows) {      if (tmpWin.windowLevel == UIWindowLevelNormal) {        window = tmpWin;        break;      }    }  }  id nextResponder = nil;  UIViewController *appRootVC = window.rootViewController;  //1、通过present弹出VC，appRootVC.presentedViewController不为nil  if (appRootVC.presentedViewController) {    nextResponder = appRootVC.presentedViewController;  }else{    //2、通过navigationcontroller弹出VC    NSLog(@"subviews == %@",[window subviews]);    UIView *frontView = [[window subviews] objectAtIndex:0];    nextResponder = [frontView nextResponder];  }  //1、tabBarController  if ([nextResponder isKindOfClass:[UITabBarController class]]){    UITabBarController * tabbar = (UITabBarController *)nextResponder;    UINavigationController * nav = (UINavigationController *)tabbar.viewControllers[tabbar.selectedIndex];    //或者 UINavigationController * nav = tabbar.selectedViewController;    result = nav.childViewControllers.lastObject;  }else if ([nextResponder isKindOfClass:[UINavigationController class]]){    //2、navigationController    UIViewController * nav = (UIViewController *)nextResponder;    result = nav.childViewControllers.lastObject;  }else{//3、viewControler    result = nextResponder;  }  return result;}