Briefly describes the reasons for priority ordering of the Android system foreground process, visible processes, service processes, background processes, and empty processes.

First High: foreground process

The foreground process is the most important process in the Android system and is the process of interacting with the user.

Second High: Visible process

Visible process refers to a part of the program interface can be seen by the user, but not in the foreground and user interaction.

Third High: Service process

A process that contains a started service is a service process, the service does not have a user interface, does not interact directly with the user, but is able to run in the background for a long time, providing important functions that the user cares about.

IV High: Background process

If a process does not contain any services that are already started, and there is no activity visible to the user, then the process is a background process.

V High: Empty process

An empty process is a process that does not contain any active components. When the system resources are tight, it is first clear.

Briefly describes the reasons for priority ordering of the Android system foreground process, visible processes, service processes, background processes, and empty processes.