The latest Beta 2 for the upcoming Android 15 release introduces desktop windowing for tablets as a developer preview. The new feature makes it possible to manage "freeform windows" that users can create to display multiple apps and resize or move around similarly to what they would do on a desktop computer.
Desktop windowing on Android tablets creates new opportunities for your apps, particularly around productivity and multitasking. The possibility to resize and reposition multiple app windows allows users to easily compare documents, reference information while composing emails, and multitask efficiently.
The desktop windowing feature includes a refreshed System UI and new APIs for developers that make it possible to run multiple apps side-by-side simultaneously, with each app contained in its own window. Similarly to desktop UIs, app windows include an header bar to minimize, maximize, and move them. Apps can also customize the header bar content, for example by displaying tabs, buttons, a dropdown menu, and so on.
To better manage all the windows a user creates, the System UI provides a fixed Taskbar showing running apps as well as shortcuts to quickly launch apps that are used more often. Users can also quickly and easily switch between full-size mode, Android's default where each app is displayed fullscreen, and destop windowing mode.
For developers, making their apps ready to take advantage of desktop windowing means implementing layout optimizations to adapt to different screen sizes and device configurations. This requirement corresponds to what Google labels Tier 2 support for large screens, which is less demanding than the top tier, Tier 1, where apps are specifically designed for different form factors, including tablets, foldables, and ChromeOS. Besides being responsive or adaptive, Tier 2 apps must also support different input devices, such as keyboard, mouse, and trackpad.
For Tier 3 apps, which run full screen, developers will need to implement support for window size classes to adapt layout, content, and interaction to different windows dimensions and make sure they persist layout configuration change across sessions.
In addition to this, freeform windows naturally lead to run multiple apps simultaneously, says Google, so that developers should make their apps ready for drag and drop and avoid requiring exclusive access to resources like camera and microphone, which could also be used by other concurrent apps.
A new possibility made possible by desktop windowing is running multiple instances of the same app in separate windows, e.g., side by side. If an app supports this possibility, it can set the multi instance property for the System UI to let users launch it multiple times.
Finally, apps compatible with desktop windowing should be aware that the window header bar is always shown and app content should be lay out taking into account its coordinates so it does not get obscured.
As mentioned, desktop windowing is part of the Android 15 QPR1 Beta 2 release and can be enabled by selecting the "Enable freeform windows" option in "Developer options".