Jetpack WindowManager Sample

This sample demonstrates how to use the new Jetpack WindowManager library. This library allows an application to support new device form factors as well as provide a common API surface for new Window Manager features throughout old and new platform versions. The initial release as well as this sample focuses on foldable devices, and will be extended to support more display types and window features.

Introduction

New foldable devices are appearing on the market that provide a set of unique hardware features. Optimizing your app for these new devices and form-factors allow you to bring a differentiating experience and allow your users to take full advantage of whatever device they are on. The Jetpack WindowManager library allows you to handle all of these devices through a common API as well as through different versions of Android.

You can determine what DisplayFeaturess are available on the device and their Rect location. The alpha02 release introduces a new DisplayFeature class with an updated callback contract to notify your application when a DisplayFeature changes. You can register/unregister the callback using these methods:

registerLayoutChangeCallback(@NonNull Executor executor, @NonNull Consumer<WindowLayoutInfo> callback)
unregisterLayoutChangeCallback(@NonNull Consumer<WindowLayoutInfo> callback)

The WindowLayoutInfo contains a list of the instances of DisplayFeature that are located within the window.

The FoldingFeature class implements the DisplayFeature interface, which includes information about these types of features:

TYPE_FOLD
TYPE_HINGE

And their possible folding states:

STATE_FLAT
STATE_HALF_OPENED
STATE_FLIPPED

To access the new state you can use the FoldingFeature information returned to the registered callback:

class LayoutStateChangeCallback : Consumer<WindowLayoutInfo> {
    override fun accept(newLayoutInfo: WindowLayoutInfo) {
        // TODO
        // Check newLayoutInfo. getDisplayFeatures()
        // to see if it is a FoldingFeature and retrieve the information
    }
}

You can see an example of this in the SplitLayoutActivity class.

WindowMetrics

The WindowManager library includes a new WindowMetrics API to get information about your current window state and the maximum window size for the current state of the system.

The API results don’t include information about the system insets such as the status bar or action bar, since those values aren’t available before the first layout pass. These bounds also don’t react to any changes in layout params that might occur when your layout is inflated. If you are looking for specific information for laying out views you should get the width/height from the Configuration object or the DecorView.

To access these APIs, you need to get an instance of the WindowManager object.

var windowManager = WindowManager(this /* context */)

From here you now have access to the WindowMetrics APIs and can easily call

windowManager.currentWindowMetrics
windowManager.maximumWindowMetrics

Notes

This is the second Alpha release of the library so the API surface may still change and grow with time. Any feedback is greatly appreciated on things you would like to see added or changed!

For more information on the Jetpack Window Manager library, see the Jetpack Window Manager release page.

Pre-requisites

• Android SDK 30
• Android Studio 4.1.2
• Android Support Repository

Getting Started

This sample uses the Gradle build system. To build this project, use the "gradlew build" command or use "Import Project" in Android Studio.

Support

• Stack Overflow: http://stackoverflow.com/questions/tagged/android

If you've found an error in this sample, please file an issue: https://github.com/android/user-interface

Patches are encouraged, and may be submitted by forking this project and submitting a pull request through GitHub. Please see CONTRIBUTING.md for more details.