将数据从标签栏 controller 传输到 ViewController

Question

I have a typical ViewController:

class ViewController: UIViewController{
override func viewDidLoad() {}
}

And I also have TabBarController which displays me the number of the current scene:

class TabBarController: UITabBarController {
  override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem!) {
    if item == (self.tabBar.items as! [UITabBarItem])[0]{
      print(1)
    }
    else if item == (self.tabBar.items as! [UITabBarItem])[1]{
      print(2)
    }
  }

}

I need my ViewController to know the number of its scene. (1 or 2). How can I deliver him this number for use from TabBarController?

Answer 1

What you want to do is, add a property called number , or whatever you like, to your ViewController class.

class ViewController: UIViewController {
  var number: Int!
}

Then in tabBarController's viewDidLoad , loop through the view controllers, check if they are of type ViewController , and then set their number property to the index of the tabBarController's view controllers:

class TabBarController: UITabBarController {

  override func viewDidLoad() {
    super.viewDidLoad()
    for (index,vc) in (viewControllers!.enumerated())! {
      if let viewController = vc as? ViewController {
        vc.number = index
      }
    }
  }

  override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem!) {
    if item == (self.tabBar.items as! [UITabBarItem])[0]{
      print(1)
    }
    else if item == (self.tabBar.items as! [UITabBarItem])[1]{
      print(2)
    }
  }

}

Unless, are you wanting to set the value whenever the tab is selected?