how to disable a navigation bar button item in iOS

Question

I have created a navigation controller. In the second view (which is pushed), I have some webservice call and placing a overlay view and setting

self.view.use

Answer 1

Navigation bar button items must be toggled by referring to them via the navigationItem property.

For example:

func setupNav() {
    let saveButton = UIBarButtonItem.init(barButtonSystemItem: .save, target: self, action: #selector(onSavePressed))
    navigationItem.rightBarButtonItem = saveButton
    saveButton.isEnabled = false
  }

func validateSave() {
     saveButton.isEnabled = isConditionMet // WON'T work
      navigationItem.rightBarButtonItem.isEnabled = isConditionMet // WORKS!
}