Can we override NAVIGATION BACK BUTTON press in Xamarin.forms?

Question

Can we override navigation back button pressed in Xamarin.forms? I have one navigation back button and the one save button in navigation bar.Save button hits the web service and saves in asynchronous way. While saving although i used progressing bar, navigation back button can be pressed and hence the app crashes due to index out of range exception on navigation stack.I tried using OnDisappearing() , did not work. I wanna cancel the PopUpAsync(),if the save is not done completely, but failed to achieve that. Is there any solution for this scenario? Can we override the navigation back button press event using any custom renderer ?

Answer 1

For controlling the back button to do what I want, I used this method in Xamarin:

   public override bool OnKeyDown(Keycode HWkeyCode, KeyEvent e)
    {
        if (HWkeyCode == Keycode.Back)
        {
            StartActivity(typeof(FrontPageActivity));
            return true;
        }
        return false;
    }