Here are some important points about the Android Framework, which will be of great benefit to the understanding and research of the Android Framework in the future.
The Android system is divided into four layers: Application layer 2, FrameWork layer 3, Library layer +Android Runtime 4, Linux Kernel
AndroidFramework is in the second layer, which abstracts some basic services or devices to make Api calls to Application applications. This is using the lowest level of Java code in Android. Inside, JNI calls C, C ++ (Library) to deal with the device, and eventually to the Linux kernel. The AndroidFramework contains the following modules: ActivityManagerService: this is an Activity manager that manages the life cycle of all activities. WindowManagerService: It is the manager of the mobile phone screen, managing the details of the screen, all screen operations are ultimately through it, controlling the display, hide, and hierarchy of the screen. ComtentProvider: A content provider that gives Android the ability for one application to access another application’s data. ViewSystem: System attempts to measure, arrange, and draw lists, grids, text, and buttons. Notification Manager The Notification Manager is responsible for managing notifications. PackageMangerService Manages package information. Telephoney Manager Communication Manager Resoure Manager Location Manager Location Manager Xmpp Manager Push Manager. Java is responsible for layout arrangement, drawing, measurement and event distribution, keystroke events. ActivityManagerService. Java management all application Activity such as WindowManagerService. Java assign all application Windows, and manage these Windows.