material-components_material-components-android/docs/foundations/PredictiveBack.md

Predictive Back

Predictive Back is a navigation pattern tied to gesture navigation which shows the user a glimpse of where swiping back will bring them. Before completing a swipe, the user can decide to continue to the previous view or stay in the current view.

In Android T (13), the OS introduced support for predictive back-to-home, which shows the user a preview of the home screen when swiping back to exit an app.

With Android U (14), the OS adds support for in-app predictive back, which apps can take advantage of to show the user previous destinations when swiping back within the app itself.

Design & API documentation

• Material Design guidelines: Predictive Back (coming soon)
• Framework & AndroidX Predictive Back developer guide

Usage

To opt in to predictive back, apps must:

1. Migrate from the legacy back handling APIs (Activity#onBackPressed, KeyEvent.KEYCODE_BACK, etc.) to the more recently introduced "back callback" APIs (OnBackAnimationCallback, OnBackPressedCallback, etc.). This involves flipping the android:enableOnBackInvokedCallback manifest flag to true, and registering callbacks to handle back pressed on Android T and above. More details on this general back migration can be found at the Framework & AndroidX Predictive Back developer guide.

2. Upgrade to MDC-Android library version 1.10.0-alpha01 (coming soon) or above.

Once completing these steps, you will get most of the predictive back animations within Material Components for free on Android U devices. See the section below to understand which components support predictive back and to learn about special considerations for each component.

Predictive Back Material Components

The following Material Components support predictive back behavior and animations:

• Search bar
• Bottom sheet
• Side sheet (support coming soon)
• Navigation drawer
• Navigation bar / Bottom navigation view (support coming soon)
• Navigation rail (support coming soon)