Tab Bar scroll to the top of UIViewController when pressed twice












2














I'm trying to make my UITabBarController scroll to the top of the page when pressed twice. I have tried several times to get this to work with no luck. As of now, I only have one class for the UITabBarController on the storyboard that is linked to the code. Am I supposed to link UITabBar as well? Here's my code that I've attempted so far.



  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) {
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
}
}









share|improve this question





























    2














    I'm trying to make my UITabBarController scroll to the top of the page when pressed twice. I have tried several times to get this to work with no luck. As of now, I only have one class for the UITabBarController on the storyboard that is linked to the code. Am I supposed to link UITabBar as well? Here's my code that I've attempted so far.



      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) {
    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
    }
    }









    share|improve this question



























      2












      2








      2







      I'm trying to make my UITabBarController scroll to the top of the page when pressed twice. I have tried several times to get this to work with no luck. As of now, I only have one class for the UITabBarController on the storyboard that is linked to the code. Am I supposed to link UITabBar as well? Here's my code that I've attempted so far.



        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) {
      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
      }
      }









      share|improve this question















      I'm trying to make my UITabBarController scroll to the top of the page when pressed twice. I have tried several times to get this to work with no luck. As of now, I only have one class for the UITabBarController on the storyboard that is linked to the code. Am I supposed to link UITabBar as well? Here's my code that I've attempted so far.



        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) {
      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
      }
      }






      swift xcode uiviewcontroller uitabbarcontroller uitabbar






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      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 13 '18 at 4:47

























      asked Nov 13 '18 at 3:13









      Nigel Denny

      697




      697
























          2 Answers
          2






          active

          oldest

          votes


















          1














          For example:



             var pressedCount: Int = 0

          func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem) {

          pressedCount += 1
          if pressedCount > 1 {
          scrollToTop(view: self.view)
          } else {
          //do something for first press
          }
          }





          share|improve this answer





















          • Do I make a new controller for UITabBar or do I implement this into the rest of my code
            – Nigel Denny
            Nov 13 '18 at 4:40










          • try typing in func tabBarController(_ and look for didSelectItem
            – Alex Bailey
            Nov 13 '18 at 4:42












          • if you know how to call an action if the tab bar is pressed once just use this code to increment on that action.
            – Alex Bailey
            Nov 13 '18 at 4:43










          • I've edited my code and I can now track when the tab bar is pressed, where would I implement your code
            – Nigel Denny
            Nov 13 '18 at 4:48










          • inside the function where the tab bar is pressed add pressedCount += 1 if pressedCount > 1 { scrollToTop(view: self.view) } else { //do something for first press } }
            – Alex Bailey
            Nov 13 '18 at 4:49



















          0














          Customize the UITabBar and then use the notification time to make the outside world respond!Or record the number of clicks through the UITabBarController agent and then notify the outside world to respond!






          share|improve this answer

















          • 1




            A little new to coding, could you give me an example of this?
            – Nigel Denny
            Nov 13 '18 at 3:59











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          2 Answers
          2






          active

          oldest

          votes








          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          1














          For example:



             var pressedCount: Int = 0

          func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem) {

          pressedCount += 1
          if pressedCount > 1 {
          scrollToTop(view: self.view)
          } else {
          //do something for first press
          }
          }





          share|improve this answer





















          • Do I make a new controller for UITabBar or do I implement this into the rest of my code
            – Nigel Denny
            Nov 13 '18 at 4:40










          • try typing in func tabBarController(_ and look for didSelectItem
            – Alex Bailey
            Nov 13 '18 at 4:42












          • if you know how to call an action if the tab bar is pressed once just use this code to increment on that action.
            – Alex Bailey
            Nov 13 '18 at 4:43










          • I've edited my code and I can now track when the tab bar is pressed, where would I implement your code
            – Nigel Denny
            Nov 13 '18 at 4:48










          • inside the function where the tab bar is pressed add pressedCount += 1 if pressedCount > 1 { scrollToTop(view: self.view) } else { //do something for first press } }
            – Alex Bailey
            Nov 13 '18 at 4:49
















          1














          For example:



             var pressedCount: Int = 0

          func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem) {

          pressedCount += 1
          if pressedCount > 1 {
          scrollToTop(view: self.view)
          } else {
          //do something for first press
          }
          }





          share|improve this answer





















          • Do I make a new controller for UITabBar or do I implement this into the rest of my code
            – Nigel Denny
            Nov 13 '18 at 4:40










          • try typing in func tabBarController(_ and look for didSelectItem
            – Alex Bailey
            Nov 13 '18 at 4:42












          • if you know how to call an action if the tab bar is pressed once just use this code to increment on that action.
            – Alex Bailey
            Nov 13 '18 at 4:43










          • I've edited my code and I can now track when the tab bar is pressed, where would I implement your code
            – Nigel Denny
            Nov 13 '18 at 4:48










          • inside the function where the tab bar is pressed add pressedCount += 1 if pressedCount > 1 { scrollToTop(view: self.view) } else { //do something for first press } }
            – Alex Bailey
            Nov 13 '18 at 4:49














          1












          1








          1






          For example:



             var pressedCount: Int = 0

          func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem) {

          pressedCount += 1
          if pressedCount > 1 {
          scrollToTop(view: self.view)
          } else {
          //do something for first press
          }
          }





          share|improve this answer












          For example:



             var pressedCount: Int = 0

          func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem) {

          pressedCount += 1
          if pressedCount > 1 {
          scrollToTop(view: self.view)
          } else {
          //do something for first press
          }
          }






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 13 '18 at 4:36









          Alex Bailey

          370316




          370316












          • Do I make a new controller for UITabBar or do I implement this into the rest of my code
            – Nigel Denny
            Nov 13 '18 at 4:40










          • try typing in func tabBarController(_ and look for didSelectItem
            – Alex Bailey
            Nov 13 '18 at 4:42












          • if you know how to call an action if the tab bar is pressed once just use this code to increment on that action.
            – Alex Bailey
            Nov 13 '18 at 4:43










          • I've edited my code and I can now track when the tab bar is pressed, where would I implement your code
            – Nigel Denny
            Nov 13 '18 at 4:48










          • inside the function where the tab bar is pressed add pressedCount += 1 if pressedCount > 1 { scrollToTop(view: self.view) } else { //do something for first press } }
            – Alex Bailey
            Nov 13 '18 at 4:49


















          • Do I make a new controller for UITabBar or do I implement this into the rest of my code
            – Nigel Denny
            Nov 13 '18 at 4:40










          • try typing in func tabBarController(_ and look for didSelectItem
            – Alex Bailey
            Nov 13 '18 at 4:42












          • if you know how to call an action if the tab bar is pressed once just use this code to increment on that action.
            – Alex Bailey
            Nov 13 '18 at 4:43










          • I've edited my code and I can now track when the tab bar is pressed, where would I implement your code
            – Nigel Denny
            Nov 13 '18 at 4:48










          • inside the function where the tab bar is pressed add pressedCount += 1 if pressedCount > 1 { scrollToTop(view: self.view) } else { //do something for first press } }
            – Alex Bailey
            Nov 13 '18 at 4:49
















          Do I make a new controller for UITabBar or do I implement this into the rest of my code
          – Nigel Denny
          Nov 13 '18 at 4:40




          Do I make a new controller for UITabBar or do I implement this into the rest of my code
          – Nigel Denny
          Nov 13 '18 at 4:40












          try typing in func tabBarController(_ and look for didSelectItem
          – Alex Bailey
          Nov 13 '18 at 4:42






          try typing in func tabBarController(_ and look for didSelectItem
          – Alex Bailey
          Nov 13 '18 at 4:42














          if you know how to call an action if the tab bar is pressed once just use this code to increment on that action.
          – Alex Bailey
          Nov 13 '18 at 4:43




          if you know how to call an action if the tab bar is pressed once just use this code to increment on that action.
          – Alex Bailey
          Nov 13 '18 at 4:43












          I've edited my code and I can now track when the tab bar is pressed, where would I implement your code
          – Nigel Denny
          Nov 13 '18 at 4:48




          I've edited my code and I can now track when the tab bar is pressed, where would I implement your code
          – Nigel Denny
          Nov 13 '18 at 4:48












          inside the function where the tab bar is pressed add pressedCount += 1 if pressedCount > 1 { scrollToTop(view: self.view) } else { //do something for first press } }
          – Alex Bailey
          Nov 13 '18 at 4:49




          inside the function where the tab bar is pressed add pressedCount += 1 if pressedCount > 1 { scrollToTop(view: self.view) } else { //do something for first press } }
          – Alex Bailey
          Nov 13 '18 at 4:49













          0














          Customize the UITabBar and then use the notification time to make the outside world respond!Or record the number of clicks through the UITabBarController agent and then notify the outside world to respond!






          share|improve this answer

















          • 1




            A little new to coding, could you give me an example of this?
            – Nigel Denny
            Nov 13 '18 at 3:59
















          0














          Customize the UITabBar and then use the notification time to make the outside world respond!Or record the number of clicks through the UITabBarController agent and then notify the outside world to respond!






          share|improve this answer

















          • 1




            A little new to coding, could you give me an example of this?
            – Nigel Denny
            Nov 13 '18 at 3:59














          0












          0








          0






          Customize the UITabBar and then use the notification time to make the outside world respond!Or record the number of clicks through the UITabBarController agent and then notify the outside world to respond!






          share|improve this answer












          Customize the UITabBar and then use the notification time to make the outside world respond!Or record the number of clicks through the UITabBarController agent and then notify the outside world to respond!







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 13 '18 at 3:46









          itzhangbao

          1




          1








          • 1




            A little new to coding, could you give me an example of this?
            – Nigel Denny
            Nov 13 '18 at 3:59














          • 1




            A little new to coding, could you give me an example of this?
            – Nigel Denny
            Nov 13 '18 at 3:59








          1




          1




          A little new to coding, could you give me an example of this?
          – Nigel Denny
          Nov 13 '18 at 3:59




          A little new to coding, could you give me an example of this?
          – Nigel Denny
          Nov 13 '18 at 3:59


















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