How to check if a TabBar item is already present before adding at run time?

Question

I have a tab bar project with one tab in the beginning and the view controller has buttons. If a button is tapped - a specific view controller is expected to be added to the tabbarcontroller/tab items. But each time I press the button the same viewcontroller/tab item is being added (multiple tab items of the same). I am trying to limit one tab item for one Viewcontroller, regardless how many times the button is tapped. Any help would be appreciated.

 -(IBAction) buttontap:id(sender){
UITableViewController*TableView = [mainStoryBoard instantiateViewControllerWithIdentifier:@"Table A"];
       TableView.title = @"Table A";

 NSMutableArray *TabBarItems = [NSMutableArray arrayWithArray:self.tabBarController.viewControllers];


if ([self.tabBarController.tabBarItem.title.description isEqualToString:@"Table A"])
    {
  [TabBarItems addObject:nil];

  }
 else
  {
  [TabBarItems addObject:TableView];
    TableView.tabBarItem.image = [UIImage imageNamed:@"contents.png"];

 }
    [self.tabBarController setViewControllers:TabBarItems];

 }

Answer 1

you could declare Tableview in your header file like so:

UITableViewController *TableView;

Now you can check if the Viewcontroller already exists:

if(!TableView){
    //your code here
    //instantiate TableView ad add it to the TabBar.

}

That way, it will only be executed on the first buttonTap.

EDIT:

Of course this wold require you to declare a ViewController for every button you have. A more dynamic approach would be to use that mutable Array you create and compare each of the items to the newly created viewController using -(BOOL)isEqual::

UITableViewController*TableView = [mainStoryBoard instantiateViewControllerWithIdentifier:@"Table A"];
NSMutableArray *TabBarItems = [NSMutableArray arrayWithArray:self.tabBarController.viewControllers];
BOOL found = NO;
for (UIViewController *vc in TabBarItems){
    if([vc isEqual:TableView]){
         found=YES;
    }
}
if(!found){
    [TabBarItems addObject:TableView];
     TableView.tabBarItem.image = [UIImage imageNamed:@"contents.png"];
    [self.tabBarController setViewControllers:TabBarItems];

}

Now you can add more buttons without adding more variables to your header. Have fun.