The the back button does different things, depending on which page is currently showing. For example, in the login page there is a 2-step process: first the user enters the username and presses “Next”, and then the password input shows up. If the user hits the hardware back button then it goes back to the username prompt. It’s just part of the requirements for the mobile app that I’m building. I don’t have the option of using something other than the hardware back button, because that is what is specified.
Having a single back-button callback registered globally when the app loads is going to be tricky. The callback code is going to have to somehow reach in to the Vue.JS components that are currently active and perform complex logic. Doing all that in a global callback means exposing all the inner workings of the various views/pages so they can be manipulated by a global callback. Yuck…