Android ActivityManager vs WindowManager

Question

Can someone please explain below in detail,

1- What is the use of ActivityManager & WindowManager?
2- What is the difference between ActivityManager & WindowManager?

Answer 1

Window Manager :- It is responsible for organizing the screen. It allocates surface and decide where they(Applications) go and how they are layered. At create surface for all the applications and they draw directly into the surface without going through the Window Manager.

Activity Manager:- Using the Activity Manager, the Android System manages a stack of activities which are in different states (starting, running, paused, stopped, destroyed).

Some basic things regarding activitys, windows and surfaces.

-An activity has one or more windows (e.g. dialogs)
-A window has one or more surfaces (e.g. surface views)
-However, in window manager, a window is called a session
-A surface is called a window
-And an activity becomes roughly a token

for getting information regarding Applications key concepts, activities and resources check this link