Improved Back button support in custom mobile apps for Android
In a custom mobile app for Android, you can press the Back hardware button to go back, instead of exiting the app. Custom mobile apps now function in the same way as native Android apps. For example, you can close a dialog box, dismiss an overlay, or collapse an expanded section by pressing the Back hardware button. On the home screen, pressing the Back hardware button displays a confirmation message before you can exit the app.