view move up in particular textfield delegate - swift

Question

I have to move the UIView in only last UITextField in Swift 3.0 on mentioned below delegate method using tag,
func textFieldDidBeginEditing(_ textField: UITextField) {
if (textField.tag == 4){
//UIView Up
}
}
func textFieldShouldEndEditing(_ textField: UITextField) -> Bool {
if (textField.tag == 4){
//UIView Down
}
return true
}
I tried many codes but none of them are working like notification,..etc.

Answer 1

You need to add Observers into the NotificationCenter for listening to both when Keyboard goes up and down (i'll assume your textfield outlet is lastTextField for this example to work but this obviously have to be adapted to whatever name you've had provide for it)
IBOutlet weak var passwordTextField: UITextField!
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(_:)), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(_:)), name: .UIKeyboardWillHide, object: nil)
(Code above can be added in viewDidLoad())
Then you add methods to be executed when those notifications arrive, like this:
func keyboardWillShow(_ notification:Notification) {
if view.frame.origin.y >= 0 && lastTextField.isFirstResponder {
view.frame.origin.y -= getKeyboardHeight(notification)
}
}
func keyboardWillHide(_ notification:Notification) {
if view.frame.origin.y < 0 {
view.frame.origin.y += getKeyboardHeight(notification)
}
}
Validations within those methods prevent double execution like moving up/down twice when moving between textfields without resigning first responder which is common in cases like your (i assume your doing this for a form hence the clarification you only need it for the fourth textfield). Notice i'm only doing validation in for the specified textfield (with its outlet lastTextField) in the keyboardWillShow method, this in case you move thor another textfield while the keyboard is shown and resign responder from it in which case, even though it isn't the original place where you started, the view will return to its original place when the keyboard is hidden.
You'll also need a method for getting keyboard's height, this one can help with that:
func getKeyboardHeight(_ notification:Notification) -> CGFloat {
let userInfo = notification.userInfo
let keyboardSize = userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue // of CGRect
return keyboardSize.cgRectValue.height
}
Let me know how it goes but i just tested this same code on my app and it works so you should be fine.
PS: pay close attention to the storyboard (if you're using it) and that delegate for textfields are set up properly.

Answer 2

The problem you are trying to remedy is rather complicated, because it requires you to:
Find the textField which is firstResponder
Calculate where that TextField is relative to it's superViews
Determine the distance for the animation, so that the containing
superview doesnt jump out of the window, or jumps too
much/repeatedly
Animate the proper superView.
As you can see.. it's quite the algorithm. But luckily, I can help. However, this only works for a hierarchy which has the following layout:
superView (view in the case of UIViewController) > (N)containerSubviews > textFields
where N is an integer
or the following:
superView (view in the case of UIViewController) > textFields
The idea is to animate superView, based on which textField is firstResponser, and to calculate if it's position inside of the SCREEN implies that it either partially/totally obstructed by the Keyboard or that it is not positioned the way you want for editing. The advantage to this, over simply moving up the superView when the keyboard is shown in an arbitrary manner, is that your textField might not be positioned properly (ie; obstructed by the statusbar), and in the case where your textfields are in a ScrollView/TableView or CollectionView, you can simply scroll the texfield into the place you want instead. This allows you to compute that desired location.
First you need a method which will parse through a given superView, and look for which of it's subViews isFirstResponder:
func findActiveTextField(subviews : [UIView], textField : inout UITextField?) {
for view in subviews {
if let tf = view as? UITextField {
guard !tf.isFirstResponder else {
textField = tf; break
return
}
} else if !subviews.isEmpty {
findActiveTextField(subviews: view.subviews, textField: &textField)
}
}
}
Second, to aleviate the notification method, also make a method to manage the actual animation:
func moveFromDisplace(view: UIView, keyboardheight: CGFloat, comp: #escaping (()->())) {
//You check to see if the view passed is a textField.
if let texty = view as? UITextField {
//Ideally, you set some variables to animate with.
//Next step, you determine which textField you're using.
if texty == YourTextFieldA {
UIView.animate(withDuration: 0.5, animations: {
self./*the proper superView*/.center.y = //The value needed
})
comp()
return
}
if texty == YourTextFieldB {
// Now, since you know which textField is FirstResponder, you can calculate for each textField, if they will be cropped out by the keyboard or not, and to animate the main view up accordingly, or not if the textField is visible at the time the keyboard is called.
UIView.animate(withDuration: 0.5, animations: {
self./*the proper superView*/.center.y = //The Value needed
})
comp()
return
}
}
}
Finally, the method which is tied to the notification for the keyboardWillShow key; in this case, i have a UIViewController, with an optional view called profileFlow containing a bunch of UITextFields
func searchDisplace(notification: NSNotification) {
guard let userInfo:NSDictionary = notification.userInfo as NSDictionary else { return }
guard let keyboardFrame:NSValue = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as? NSValue else { return }
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
let keybheight = keyboardHeight
var texty : UITextField? //Here is the potential textfield
var search : UISearchBar? //In my case, i also look out for searchBars.. So ignore this.
guard let logProfile = profileFlow else { return }
findActiveTextField(subviews: [logProfile], textField: &texty)
//Check if the parsing method found anything...
guard let text = texty else {
//Found something.. so determine if it should be animated..
moveFromDisplace(view: searchy, keybheight: keybheight, comp: {
value in
search = nil
})
return
}
//Didn't find anything..
}
Finally, you tie in this whole logic to the notification:
NotificationCenter.default.addObserver(self, selector: #selector(searchDisplace(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
I can't provide more content to the code, since it all depends on your view hierarchy, and how you want things to animate. So it's up to you to figure that out.
On a side note, usually, if you have so many textfields that to lay them out properly means they overstep the length of the screen.. it's probable that you could simplify your layout. A way to make this algorithm better would be to make sure you have all your textfields in one containing view, which again can become heavy for when, say, you use AutoLayout constraints. Odds are if you're in this situation, you can probably afford to add a flow of several views etc.
There is also the fact that i've never really needed to use this for iPhone views, more for iPad views, and even then for large forms only (e-commerce). So perhaps if you're not in that category, it might be worth reviewing your layout.
Another approach to this, is to use my approach, but to instead check for specific textFields right in the findActiveTextField() method if you only have a handful of textfields, and to animate things within findActiveTextField() as well if you know all of the possible positions they can be in.
Either way, i use inout parameters in this case, something worth looking into if you ask me.