Link UIButton To A Specific Tab Within Several Different Tab Bar Controllers - ios

Question

I have an 'Enter' button on my app index/main page.
This button links to one of two (2) different tab bar controllers - depending on whether the user has purchased full access or not. Each tab bar controller has 3 tabs.
These two (2) tab bar controllers are named "TabBarControllerFree" and "TabBarControllerPaid" respectively.
I have written the following code to determine where the user is 'sent':
#IBAction func Enter(sender: AnyObject) {
//Check if product is purchased
if (defaults.boolForKey("purchased")){
print("User has purchased")
// Send User To Paid TabBarController - FULL Access:
let vc = self.storyboard!.instantiateViewControllerWithIdentifier("TabBarControllerPaid") as! TabBarControllerPaid
self.presentViewController(vc, animated: true, completion: nil)
}
else if (!defaults.boolForKey("purchased")){
print("user has NOT purchased")
// Send User To Free TabBarController - PARTIAL Access:
let vc = self.storyboard!.instantiateViewControllerWithIdentifier("TabBarControllerFree") as! TabBarControllerFree
self.presentViewController(vc, animated: true, completion: nil)
}
}
At present, the user is sent to the first tab within the respective Tab Bar Controllers by default (index 0 or the left-most tab).
I would like to have the option of sending the user to the second tab (index 1) or third tab (index 2).
I realise I have to effect "SelectedIndex = 1" or "SelectedIndex = 2" into my code.
How can I do this please?
** ADDITIONAL INFO **
This is a snapshot of my storyboard map:
Basically, I have three (3) buttons (green colour) on my initial VC (the landing page).
(1) If the user clicks 'Enter', I check if they have full access or not, and send them to the respective Paid or Free Tab Bar Controller (red arrows).
(2) If the user clicks 'Workouts' I send them to the same Tab Bar Controllers in the same manner as the first/left most (index 0) tabs on both are 'Workouts' (yellow arrows).
(3) If the user clicks 'Exercises' I would like to send them to the second left most tab (index 1) in respective Paid or Free Tab Bar Controllers (blue arrows).
It is button three (3) for 'Exercises' that I am struggling to execute effectively.

Answer 1

In order for this to work, you have to change some settings in Xcode. Select the target. Go to the General tab. Where it says Main Interface, make it blank.
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
// Add this
var mainViewController: UITabBarController?
var isPaid: Bool {
get {
let defaults = NSUserDefaults.standardUserDefaults()
let saveIt = defaults.objectForKey("isPaid") as? Bool ?? false
return saveIt
}
set(newBool) {
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setObject(newBool, forKey: "isPaid")
}
}
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
if isPaid {
mainViewController = mainStoryboard.instantiateViewControllerWithIdentifier("TabControllerPaid") as? UITabBarController
}
else {
mainViewController = mainStoryboard.instantiateViewControllerWithIdentifier("TabControllerFree") as? UITabBarController
}
mainViewController?.selectedIndex = 0
self.window?.rootViewController = mainViewController
self.window?.makeKeyAndVisible()
}
// .......
}