In Android 7.0 and later, users can have multiple apps simultaneously displayed on their device screen with the new platform feature, multi-window. In addition to the default implementation of multi-window, Android also supports a few varieties of multi-window:

• Split-screen is the base implementation of multi-window and provides two activity panes for users to place apps.
• Freeform allows users to dynamically resize the activity panes and have more than two apps visible on their screen.
• Picture-in-picture (PIP) allows Android devices to continue playing video content in a small window while the user interacts with other applications.

To implement the multi-window feature, device manufacturers set a flag in the config file on their devices to enable or disable multi-window support.

Implementation

Multi-window support is enabled by default in Android 7.0 and later. To disable it, set the config_supportsMultiWindow flag to false in the config.xml file.

For devices that declare ActivityManager.isLowRam(), multi-window is disabled regardless of the value of config_supportsMultiWindow flag.

Split-screen

The default multi-window experience is split-screen mode, where the System UI is divided directly down the middle of the device in portrait or landscape. Users can resize the window by dragging the dividing line side-to-side or top-to-bottom, depending on the device orientation.

Then device manufacturers can choose if they want to enable freeform or PIP.

Freeform

After enabling standard multi-window mode with the flag config_supportsMultiWindow, device manufacturers can optionally allow freeform windowing. This mode is most useful for manufacturers of larger devices, like tablets.

To support freeform mode, enable the PackageManager#FEATURE_FREEFORM_WINDOW_MANAGEMENT system feature in /android/frameworks/base/core/java/android/content/pm/PackageManager.java and set config_freeformWindowManagement to true in config.xml.

<bool name="config_freeformWindowManagement">true</bool>

Picture-in-picture

After enabling standard multi-window mode with the flag config_supportsMultiWindow, device manufacturers can support picture-in-picture to allow users to continue watching video while browsing other activities. While this features is primarily targeted at Android Television devices, other device form factors may support this feature.

To support PIP, enable the PackageManager#FEATURE_PICTURE_IN_PICTURE system feature in /android/frameworks/base/core/java/android/content/pm/PackageManager.java.

System UI

Support all standard System UIs according to https://developer.android.com/guide/topics/ui/multi-window.html#testing

Applications

To support multi-window mode for preloaded apps, consult the Android developer documentation.

Validation

To validate their implementation of multi-window, device manufacturers should run CTS tests and follow the testing instructions for multi-window.