Myujth

I recently implemented into my code a way to scroll to the top of UIViewController by tapping an icon in UITabBar twice. The code is located inside my UITabBarController code. It works great, however the unfortunate side effect I've found is that every time I open up a page on my app, it's now at the top of UIViewController instead of the place where I last left off. I'm sure there's an error somewhere in this code

 import UIKit

class TabViewController: UITabBarController, UITabBarControllerDelegate 
 var pressedCount: Int = 0


 override func viewDidLoad() 
 super.viewDidLoad()
 self.delegate = self


 // Do any additional setup after loading the view.
 
 @IBAction func unwindToMain(segue: UIStoryboardSegue) 

 override func viewWillAppear(_ animated: Bool) 

 super.viewWillAppear(animated)

 self.navigationController?.isNavigationBarHidden = true
 

 override func didReceiveMemoryWarning() 
 super.didReceiveMemoryWarning()
 // Dispose of any resources that can be recreated.
 
 override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) 
 pressedCount += 1
 if pressedCount > 1 
 scrollToTop()
 else 
 //do something for first press
 
 print("Selected item")
 

 // UITabBarControllerDelegate
 func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) 
 print("Selected view controller")
 
 func tabBarController(_ TabViewController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool 
 guard let viewControllers = viewControllers else return false 
 if viewController == viewControllers[selectedIndex] 
 if let nav = viewController as? UINavigationController 
 guard let topController = nav.viewControllers.last else return true 
 if !topController.isScrolledToTop 
 topController.scrollToTop()
 return false
 else 
 nav.popViewController(animated: true)
 
 return true
 
 

 return true
 



extension UIViewController 
 func scrollToTop() 
 func scrollToTop(view: UIView?) 
 guard let view = view else return 

 switch view 
 case let scrollView as UIScrollView:
 if scrollView.scrollsToTop == true 
 scrollView.setContentOffset(CGPoint(x: 0.0, y: -scrollView.contentInset.top), animated: true)
 return
 
 default:
 break
 

 for subView in view.subviews 
 scrollToTop(view: subView)
 
 

 scrollToTop(view: view)
 

 var isScrolledToTop: Bool 
 if self is UITableViewController 
 return (self as! UITableViewController).tableView.contentOffset.y == 0
 
 for subView in view.subviews 
 if let scrollView = subView as? UIScrollView 
 return (scrollView.contentOffset.y == 0)
 
 
 return true
 

Problem is, that when your ViewController disappear, it still has pressedCount property set to 2

So to viewWillAppear add this line to reset this:

pressedCount = 0

also fix if statement in tabBar didSelect item to reset pressedCount every time user presses tabBar item twice

if pressedCount > 1 
 scrollToTop()
 pressedCount = 0
 else 
 //do something for first press