MediaProjection is an Android class that facilitates capturing the screen and recording system audio.
The android.media.projection classes were introduced in Android API 21 to allow applications to record still images, video, and (potentially) audio from the device. In previous releases, applications were only allowed to capture their own rendering, and different approaches were required for View-based UI and OpenGL ES rendering.
Because capturing content outside of the current application has security implications, applications wishing to use these features must get permission from the user first. This is handled through the MediaProjectionManager.
An official screen capture example can be found on github.
The images captured by the MediaProjection are sent to a virtual display, which takes a Surface as an argument. The Surface can be provided by a SurfaceView (for immediate display), an ImageReader (for access from software), constructed from a SurfaceTexture (for use as an OpenGL ES texture), or by MediaCodec/MediaRecorder (for video encoding).
