獲取當前視圖的TopViewController

 AppDelegate *appdelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
    UIViewController* topViewController = appdelegate.baseTabBarController.navigationController.topViewController;
    NSLog(@"%@",topViewController);
     if ([topViewController isKindOfClass:[ HomeViewController class]]) {
     ｝

獲取當前視圖的RootViewController（Nav級別）

-(UIViewController *)getCurrentRootViewController {


    UIViewController *result;


    // Try to find the root view controller programmically


    // Find the top window (that is not an alert view or other window)


    UIWindow *topWindow = [[UIApplication sharedApplication] keyWindow];


    if (topWindow.windowLevel != UIWindowLevelNormal)


    {


        NSArray *windows = [[UIApplication sharedApplication] windows];


        for(topWindow in windows)


        {


            if (topWindow.windowLevel == UIWindowLevelNormal)


                break;


        }


    }


    UIView *rootView = [[topWindow subviews] objectAtIndex:0];


    id nextResponder = [rootView nextResponder];


    if ([nextResponder isKindOfClass:[UIViewController class]])


        result = nextResponder;


    else if ([topWindow respondsToSelector:@selector(rootViewController)] && topWindow.rootViewController != nil)


        result = topWindow.rootViewController;


    else


        NSAssert(NO, @"ShareKit: Could not find a root view controller.  You can assign one manually by calling [[SHK currentHelper] setRootViewController:YOURROOTVIEWCONTROLLER].");


    return result;


}