Android Component

1. PRESENTATION
TITLE
dimif51044@cnogs.com

2. AGENDA
Introduction
Primary goals
Areas of growth
Timeline
Summary
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3. ACTIVITIES IN ANDROID
Activities are said to be the presentation layer of our
applications. The UI of our application is built around one
or more extensions of the Activity class. By using
Fragments and Views, activities set the layout and display
the output and also respond to the user’s actions. An
activity is implemented as a subclass of class Activity.
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4. THE CONCEPT
OF ACTIVITIES

5. THE CONCEPT OF ACTIVITIES
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• The activity serves as the entry point for an app's interaction with the user.
• An activity provides the window in which the app draws its UI.
• Each activity can then start another activity in order to perform different
actions.
• each activity is only loosely bound to the other activities
• To use activities in your app, you must register information about them in
the app’s manifest, and you must manage activity lifecycles appropriately.

6. ACTIVITY-LIFECYCLE
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7. ACTIVITY-LIFECYCLE
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• onCreate() - This is the first callback and called when the activity is first created.
• onStart() - This callback is called when the activity becomes visible to the user.
• onResume() - This is called when the user starts interacting with the application.
• onPause() - The paused activity does not receive user input and cannot execute any code and
called when the current activity is being paused and the previous activity is being resumed.
• onStop() - This callback is called when the activity is no longer visible.
• onDestroy() - This callback is called before the activity is destroyed by the system.
• onRestart() - This callback is called when the activity restarts after stopping it.

8. EXAMPLE
This example will take you through simple steps to show Android
application activity life cycle. Follow the following steps to modify the
Android application we created in Hello World Example chapter
• You will use Android studio to create an Android application and
name it as HelloWorld under a package com.example.helloworld
as explained in the Hello World Example chapter.
• Modify main activity file MainActivity.java as explained below.
Keep rest of the files unchanged.
• Run the application to launch Android emulator and verify the
result of the changes done in the application.
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9. THANK YOU
dimif51044@cnogs.com
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