How to make NSNotificationCenter only run when a certain UITextField is selected - ios

Question

I am using NSNotificationCenter to shift the main view frame up when a keyboard is shown.
However, I only want this to work for when one UITextField is selected.
Here is what I have so far:
func getKeyboardHeight(notification: NSNotification) -> CGFloat {
let userInfo = notification.userInfo
let keyboardSize = userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue
return keyboardSize.CGRectValue().height
}
func keyboardWillShow(notification: NSNotification) {
self.view.frame.origin.y -= getKeyboardHeight(notification)
}
func keyboardWillHide(notification: NSNotification) {
self.view.frame.origin.y += getKeyboardHeight(notification)
}
func subscribeToKeyboardNotifications() {
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
}
func unsubscribeToKeyboardNotifications() {
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
}
func subscribeToKeyboardHide() {
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)
}
func unsubscribeToKeyboardHide() {
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}
In ViewWillAppear()
self.subscribeToKeyboardNotifications()
self.subscribeToKeyboardHide()
In ViewWillDisappear()
self.unsubscribeToKeyboardNotifications()
self.unsubscribeToKeyboardHide()
How do I make the view shift up when I am only selecting one specific UITextField?

Answer 1

Try this
if yourTextfield.isEditing{}
Or this
if yourTextfield.isFirstResponder{}
To check is this is your textfield

Answer 2

You can create the following extension
extension UIView {
/**
Finds the first responder
:returns: the first responder, or nil if nothing found.
*/
private func findFirstResponder() -> UIView? {
if isFirstResponder() { return self }
else {
for view in subviews as! [UIView] {
if let responder = view.findFirstResponder() {
return responder
}
}
return nil
}
}
}
Then call it like this in your keyboardWillShow
let textField = UIApplication.sharedApplication().keyWindow?.findFirstResponder() as? UITextField
You can now use textField currently active.