Introduction of Activity Lifecycle

This section describes the android.app.Activity class which represents an activity you allow the user to interact with on the screen. An activity has 4 states: Active, Paused, Stopped and Destroyed.

In the last chapter, we learned how to access the Android application environment information using the java.lang.System and android.os.Environment classes. Now let's take a closer look at the starting class of our simple applications created so far: android.app.Activity.

The android.app.Activity class represents an activity you allow the user to interact with on the screen. The android.app.Activity class takes care of creating an empty window for you to place visual content using the setContentView() method.

An Activity object has four states:

Android reference document provides the following diagram to illustrate the lifecycle of an Activity object:
Android Application Activity Object Lifecyle

The entire lifecycle of Activity object is divided into 3 nested lifetime periods:

See next tutorials on you can add code logics when the activity entering or leaving a lifetime period.

Last update: 2015.

Table of Contents

 About This Book

 Installing JDK 1.8 on Windows System

 Installation of Android SDK R24 and Emulator

 Installing Apache Ant 1.9 on Windows System

 Developing First Android Application - HelloAndroid

 Android Application Package (APK) Files

 Android Debug Bridge (adb) Tool

 Android File Systems

 Android 4.0.3 File Systems

 AboutAndroid - Application to Retrieve System Information

android.app.Activity Class and Activity Lifecycle

Introduction of Activity Lifecycle

 onCreate() and Other Callback Methods

 ActivityLog - Application to Create Log File

 Viewing Activity Log File with "cat" Command in "adb shell"

 Implementing Activity Callback Methods

 ActivityLog Test - Activity Terminated by User

 ActivityLog Test - Activity Stopped and Restarted

 ActivityLog Test - Activity Paused and Resumed

 View Objects and Layout Resource Files

 Using "adb logcat" Command for Debugging

 Build Process and Package File Content

 Building Your Own Web Browser

 Android Command Line Shell

 Samsung Galaxy Tab 3 Mini Tablet

 USB Debugging Applications on Samsung Tablet

 Android Tablet - LG-V905R

 USB Debugging Applications on LG-V905R Tablet

 Android Phone - LG-P925g

 USB Debugging Applications on LG-P925g Phone

 Outdated Tutorials

 References

 PDF Printing Version