Android Programming
Tutorial No 4 :Activity & it's Lifecycle
About Activity
Introduction
The mobile-app experience differs from its desktop development in that a user's interaction with the app doesn't always begin in the same place. Instead, the user journey often begins non-deterministically. For instance, if you open an email app from your home screen, you might see a list of emails. By contrast, if you are using a social media app that then launches your email app, you might go directly to the email app's screen for composing an email.
We can consider activity as a landing page for the user.In Website Terminology it's a welcome page or in Desktop Application , we can cosider it as a Welcome Form.
How to create an activity
For this, Please refer the video : given on this link.
How to deaclare an activity
Whenever, you create any activity - It will be added automatically in manifest file
<application ... >
<activity android:name=".ExampleActivity" />
...
</application ... >
Activity Life Cycle
Acitivity Life Cycle
1. onCreate() :- This is the first method which will be called when the activity is first created.
2. onStart() :- This method is called when the activity becomes visible to the user.
3. onResume() :- This method is called when user starts interacting with the application.
4. onPause() :- This method is called when user works with another application.
5. onStop() :- This method is called when the activity is no longer visible.
6. onDestroy() :-
This method is called before the activity is destroyed by the system.
7. onRestart() :-
This method is called when the activity restarts after stopping it.
Important Methods