What is an Android DecorView?

Question

http://developer.android.com/reference/android/view/Window.html#getDecorView():

Retrieve the top-level window decor view (containing the standard window

Answer 1

Decor view appears to contain screen resolution? I get 1920.

var verticalScreenRes = act.window.decorView.height.toFloat() // 1920

then verify

adb -s emulator-5554 shell wm size
Physical size: 1080x1920

Answer 2

Seems that one of the places where it's best defined is in Romain Guy's Blog:

The DecorView is the view that actually holds the window’s background drawable. Calling getWindow().setBackgroundDrawable() from your Activity changes the background of the window by changing the DecorView‘s background drawable. As mentioned before, this setup is very specific to the current implementation of Android and can change in a future version or even on another device.