Ionic Capacitor hardware back button is automatically closing the app

Question

My current setup is:

@capacitor/core: 3.0.0, @ionic-native/core: 5.0.7

I'm trying to change the behavior of my app to not close the app, but go back in the navigation stack. To my knowledge, the hardware back button on Android devices did not automatically close the app until I upgraded Capacitor to 3.0.0

What is confusing me though, is how I have absolutely 0 code for handling the back button functionality, and from everything I'm searching online shows the back button doing nothing by default, not automatically closing the app as the default (as mine seems to be doing). I've searched all the project files for anything to do with "platform", "backButton", and "App.Exit" and was unable to find any code that may be causing the app to close.

I've tried subscribing to the back button press event using the below code and it is never ran. The app closes instead of showing the alert dialog. I've changed the priority from 0, 10, and 99 (all priorities listed in the Ionic documentation)

this.platform.backButton.subscribeWithPriority(10, () => {
  alert('Back button pressed!');
});

Answer 1

1. Install capacitor app.

   npm install @capacitor/app

2. Import it.

   import { App as CapacitorApp } from '@capacitor/app';

3. Add back listener if can go back then we can push to back or exit the app.

   CapacitorApp.addListener('backButton', ({canGoBack}) => {
     if(!canGoBack){
       CapacitorApp.exitApp();
     } else {
       window.history.back();
     }
   });
   

Answer 2

So, I feel a bit dumb after realizing this, but it is because I had to run the below commands, because I apparently didn't update them when upgrading Capacitor a while back. Make sure all of your plugins are fully updated, yours may be different than mine.

npm install @capacitor/app
npx cap sync