Operating mechanism of Android system

In standard Windows and Linux desktop operating systems, you can run multiple applications in different windows at the same time, with only one application at the current focus state, but other applications are an equal place. Users can switch each application at any time, and users are required to close the application when the application is not needed.

But Android OS applications are not in this way.

Only one application runs at the top of Android every time, except for the status bar where the current application will fill the entire screen. The most common application of the user is the home page of the app (home application), which mainly shows the background map and application shortcuts, widgets, etc., where the user can activate the application.

When a user runs an app on Android, Android launches the program and puts it on the front end, from which the user can launch another app, or the app's own other interface, one boot. While these programs and screens are recorded in the application stack (application stack) by the active management (Android activity Manager), the user can use the Back button to return to the previous application screen at any time. This is a bit like the browser's web browsing history feature, and users can use the Back button to return to the previous app screen.

Inside Android, each user interface represents an activity class, with each activity having its own life cycle, one or more activities per application.

In Android, each application is "active" even after its process is closed. In other words, the life cycle of its activities and the life cycle of its processes are not tied together, and the process is only a one-time container of activity, unlike the standard desktop operating systems of Windows and Linux. In standard Windows and Linux desktop operating systems, you can run multiple applications in different windows at the same time, with only one application at the current focus state, but other applications are an equal place. Users can switch each application at any time, and users are required to close the application when the application is not needed.

But Android OS applications are not in this way.

Only one application runs at the top of Android every time, except for the status bar where the current application will fill the entire screen. The most common application of the user is the home page of the app (home application), which mainly shows the background map and application shortcuts, widgets, etc., where the user can activate the application.

When a user runs an app on Android, Android launches the program and puts it on the front end, from which the user can launch another app, or the app's own other interface, one boot. While these programs and screens are recorded in the application stack (application stack) by the active management (Android activity Manager), the user can use the Back button to return to the previous application screen at any time. This is a bit like the browser's web browsing history feature, and users can use the Back button to return to the previous app screen.

Inside Android, each user interface represents an activity class, with each activity having its own life cycle, one or more activities per application.

In Android, each application is "active" even after its process is closed. In other words, the life cycle of its activities and the life cycle of its processes are not tied together, and the process is only a one-time container of activity, unlike the standard desktop operating systems of Windows and Linux.

Operating mechanism of Android system