ios - Action to Navigation bar back button

Question

I want to show an alert with Confirmation when user clicks on back button. This is how I'm trying to add action.

self.navigationItem.hidesBackButton = true
let newBackButton = UIBarButtonItem(title: "<", style: UIBarButtonItemStyle.plain, target: self, action: #selector(ViewController.save(sender:)))
self.navigationItem.leftBarButtonItem = newBackButton

This is working fine but I want the default back button image in it and not the custom title. How to do that ?

I tried following code as well :

self.navigationItem.backBarButtonItem?.action = #selector(ViewController.save(sender:))

...but the action is not performed, too.

Answer 1

This might help. This wont override back action, but you can do additional task.

Objective c

-(void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    if(self.isMovingFromParentViewController)
    {
        //On click of back or swipe back
    }
    if(self.isBeingDismissed)
    {
        //Dismissed
    }
    NSLog(@"%d",self.isBeingDismissed);
    NSLog(@"%d",self.isMovingFromParentViewController);
}

Swift

override func viewWillDisappear(_ animated: Bool)
{
    super.viewWillDisappear(animated);
    if self.isMovingFromParentViewController
    {
        //On click of back or swipe back
    }
    if self.isBeingDismissed
    {
        //Dismissed
    }
}