iOS - UIButton become first responder to open keyboard - ios

Question

I need to open keyboard on button click for UIButton (not using/for UITextField). I have tried to create custom button by overriding variable canBecomeFirstResponder but it's not working.
Is there any other way to do so?
Note: I want to set UIPIckerView as an input view of UIButton in key board frame.
Here is my code.
class RespondingButton: UIButton {
override var canBecomeFirstResponder: Bool {
return true
}
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
commonInit()
}
private func commonInit() {
// common init
}
}
In my view controller, I connected button action.
class TestViewController: UIViewController {
#IBAction func testBecomeFirstResponder(button: RespondingButton){
button.becomeFirstResponder() // Not working.
}
}

Answer 1

Here is what I would do.
Create transparent textField 1x1px, lets say it is myTextField.
Then add your desired button. In the button action make the myTextField.becomeFirstResponder().
Create view:
let pvBackground: UIView = {
let v = UIView(frame: CGRect(x: 0, y: 0, width: 10, height: 10))
v.backgroundColor = .white
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
In viewDidLoad:
pvBackground.addSubview(yourPickerView)//add the picker into the pvBackground
myTextField.inputView = pvBackground
I added the pickerView into the another view to be able to customize it more.

Answer 2

Add conformance to UIKeyInput like this. It should work.
class RespondingButton: UIButton, UIKeyInput {
override var canBecomeFirstResponder: Bool {
return true
}
var hasText: Bool = true
func insertText(_ text: String) {}
func deleteBackward() {}
}