How do I pass data from a UIViewController to UITabBarController? - swift

Question

In UIViewController:
class ViewController2: UIViewController {
var points = 0
var pressed = false
#IBOutlet weak var label: UILabel!
#IBAction func slider(_ sender: UISlider) {
number = Int(sender.value)
label.text = String(number)
}
#IBAction func submitbutton(_ sender: UIButton) {
pressed = true
}
}
I am trying to do something in a TabBarController if a button in a UIViewController is pressed and also add a number to the number in another TabBarConroller.
Image 1: This shows the connection between my ViewControllers.
Image 2: This shows the first two ViewControllers.)
Image 3: This shows the third and fourth ViewController
Here is my storyboard. I've put a few words to describe what I am trying to do in the images. Please tell me if you need a clearer description. Thank you!

Answer 1

If the ViewController is a child of the UITabBarController that you want to access, you can simply use tabBarController property of the UIViewController, e.g., use this to change selected controller to the first one:
#IBAction func submitbutton(_ sender: UIButton) {
pressed = true
self.tabBarController?.selectedIndex = 0
}
So let's say that you have a custom UITabBarController subclass, e.g.:
class CustomTabBarController: UITabBarController {
func acceptData(points: Int) {
print(">>> Accepted: \(points)")
// or do anything you need to do with it
}
}
Then you can pass it data as follows:
#IBAction func submitbutton(_ sender: UIButton) {
pressed = true
if let customTabController = self.tabBarController as? CustomTabBarController {
customTabController.acceptData(points: self.points)
}
}
UPDATE
Since it seems that the current VC is presented by one of the tabBarController child controllers, you will have to access it through the self.presentingViewController:
#IBAction func submitbutton(_ sender: UIButton) {
pressed = true
if let customTabController = self.presentingViewController?.tabBarController as? CustomTabBarController {
customTabController.acceptData(points: self.points)
}
}
UPDATE 2
Your screenshot are of a very poor quality, your explanation of the problem would require a clarification too, since it is really hard to understand what you try to do. So after the whole discussion in comments I guess this is it:
#IBAction func submitbutton(_ sender: UIButton) {
pressed = true
if let tabController = self.presentingViewController?.tabBarController,
let viewController3 = tabController.viewControllers?.filter({ $0 is ViewController3 }).first {
viewController3.acceptData(points: self.points)
}
}

Answer 2

You can pass data as normally
let vc:HomeVC = ApiUtillity.sharedInstance.getCurrentLanguageStoryboard().instantiateViewController(withIdentifier: "HomeVC") as! HomeVC
vc.tempCategoryArray = CategoryArray
self.navigationController?.pushViewController(vc, animated: true)

Answer 3

In your TabBarController class, take a variable say variableToBeSet
class TabBarController: UITabBarController
{
var variableToBeSet: Int = 0 // This is just an example. You can change it as per requirement.
// Rest of class implementation
}
Now in your ViewController :
#IBAction func submitbutton(_ sender: UIButton) {
pressed = true
let tabControllerInstance = self.tabBarController as! TabBarController
tabControllerInstance.variableToBeSet = localVariable // The value which you want to assign
}