check current view controller over screen in ios

Question

I have presented a UINavigationController containing UIViewController on self object with following code

  drawController = [[DrawImageViewController alloc] initWithNibName:nil bundle:nil];
[drawController setDrawControllerDelegateObject:self];
UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:drawController];
[self presentModalViewController:nav animated:YES];
[nav release];

But when before calling the above code for second time i wanna know whether the current view controller appearing on screen is drawController. I am using following code

    if (drawController && [drawController isBeingPresented])

But it is not working for me and also it is for iOS 5.0 so i am stuck here. Please help me to know how should i come to know the current UIViewController appeared on screen is of which class and whether drawContoller is still presented on screen or not? Sorry for my typo mistakes if there is any. Any help will be appreciated.

Thanks Neha Mehta

Answer 1

Use navigationController's visibleViewController property and isKindOfClass method to know whats on top:

if([self.navigationController.visibleViewController isKindOfClass:[yourcontroller class]])
   //exists
else
   //not exists