"Android" Learning Diary first Knowledge activity

I. Introduction to the activity:

Activity is the most basic and most commonly used component of Android components, in an Android application, each activity is usually a page, and each activity is implemented as a separate class that can be understood as a JSP page in the Java EE. And each activity component inherits from the activity's base class, which will display a user interface consisting of several views controls and respond to the event

You can navigate from one screen to another by calling the StartActivity () method, and the conditions for opening the activity are encapsulated in intent.

When a new screen is opened, the previous screen is paused and saved in the history stack, and the user can return to the previous screen in the history stack, which can also be removed from the history stack when the screen is no longer in use, and by default Android will retain the run screen from the home screen to each app.

"Android" Learning Diary first Knowledge activity