Multi-window on Android was present in different forms even prior to the release of Android Nougat's multi-window functionality. But then Google gave Android a predictable and uniform implementation of multi-window support with three different multi-window modes: split-screen, freeform, and picture-in-picture (available for phones in Android Oreo).

However, the split-screen functionality, as was introduced in the past, continues to suffer from one grave limitation. While you can open two apps in split-screen view and better utilize your evergrowing screen real estate, you cannot run the two apps simultaneously. When two apps are opened in split-screen, only one app is retained as the active app at a time while the other app is paused. Users would need to manually swap app states by interacting with the app that they want as active as there was no way provided in stock Android to retain both apps as active.

While Google did provide certain recommendations on how to support multi-window to still allow for an actually useful experience, a significant number of apps did not handle the paused state according to those recommendations, leading to issues like videos getting paused or stopped or instant messages not getting updated when an app was relegated to the paused state.

This is all set to change. Thanks to Android's recently added support for foldable smartphones, Google is introducing a new feature called "multi-resume" which is set to become mandatory in Android Q.

Multi-Resume

The multi-resume feature now makes it possible for multiple apps to be open and actually be running at the same time. Google is now allowing manufacturers to keep all apps resumed/active when in multi-window. Samsung already makes this possible on their devices with the "MultiStar" module in Good Lock, but now native support is coming to all Android devices.

Multi-Window Splitscreen with Multi-Resume

Since Android Pie has already shipped, both the OEM and the app will have to opt-in in order to test this feature on an existing Android Pie device. This means that the OEM has to roll out an update to include support for multi-resume on the particular smartphone, and the app developer also needs to include a special tag in their Manifest to enable functionality for their particular app.

meta-data android:name="android.allow_multiple_resumed_activities" android:value="true"

If both the criterion are satisfied (for each app), all top activities will remain resumed on an Android Pie device.

Google expects to make multi-resume support the mandatory behaviour in the next version of Android, aka Android Q. While the feature will certainly find a lot of use on foldable devices, our current generation devices with tall displays will also stand to benefit from these improvements to multitasking.