I am writing a program using Swift 3.1 and Xcode 8.3.3. I want to create a class, responsible for moving entire view when keyboard appears and disappears. But I faced difficulties with creating custom Selector with parameters from string. To show or hide keyboard we need function:
func keyboardWillShow(notification: Notification) {
//Code moving view when keyboard appears
}
I am trying to create a selector like this:
let selector = Selector(("keyboardWillShow")
NotificationCenter.default.addObserver(view, selector: selector, name: .UIKeyboardWillShow, object: anyView.view.window)
It is compiling, but when keyboard appears, it crashes. Because it is independent class I cannot use this construction:
#selector(keyboardWillShow)
Because it transforms Swift function to Objective-C function (adding @objc). So question is: how to create a Selector form with parameters string?
P. S. I can put the whole code there but I don't want question to be very big, so I will edit question if somebody asks...
Here is what you want, Selector with string type and Notification parameter argument
Swift 4
NotificationCenter.default.addObserver(self, selector: Selector(("showKeyboard:")), name:NSNotification.Name.UIKeyboardWillShow, object: nil)
var keyboardHeight = 0.0
//-------------------
@objc func showKeyboard(_ sender: Notification) {
keyboardWillShow(sender: sender as NSNotification, adjustHeight: 150)
print("sender - \(sender)")
}
//-------------------
func keyboardWillShow(sender: NSNotification, adjustHeight: CGFloat) {
if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
keyboardHeight = Double(keyboardSize.height)
// do your calculations
}
}
Swift 3
NotificationCenter.default.addObserver(view, selector: Selector(("keyboardWillShow:")), name: .UIKeyboardWillShow, object: anyView.view.window)
func keyboardWillShow(_ notification: Notification) {
keyboardWillShow(sender: sender as NSNotification, adjustHeight: 150)
print("sender - \(sender)")
}
Here are normal selector, according to language support
Swift 4
NotificationCenter.default.addObserver(self, selector: #selector(self.showKeyboard(sender:)), name:NSNotification.Name.UIKeyboardWillShow, object: nil)
var keyboardHeight = 0.0
//-------------------
@objc func showKeyboard(sender: NSNotification) {
keyboardWillShow(sender: sender, adjustHeight: 150)
}
//-------------------
func keyboardWillShow(sender: NSNotification, adjustHeight: CGFloat) {
if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
keyboardHeight = Double(keyboardSize.height)
// your operations here
}
}
Swift 3
NotificationCenter.default.addObserver(self, selector: #selector(self.showKeyboard(sender:)), name:NSNotification.Name.UIKeyboardWillShow, object: nil)
var keyboardHeight = 0.0
//-------------------
func showKeyboard(sender: NSNotification) {
keyboardWillShow(sender: sender, adjustHeight: 150)
}
//-------------------
func keyboardWillShow(sender: NSNotification, adjustHeight: CGFloat) {
if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
keyboardHeight = Double(keyboardSize.height)
// your operations here
}
}