Android Life Cycle Methods

Hai Friends Now we are going to discuss about some Android Life Cycle Methods.

The Android Life Cycle Methods are

• onCreate()
• onRestart()
• onStart()
• onResume();
• onPause()
• onStop()
• onDestroy()
• onSaveInstanceState()

Not we are going to discuss here for all methods.

onSaveInstanceState():

It called if the activity is stopped. it used to save data.

it can restore it states if it restarted.

onPause():

It always called if the activity ends, can be used to release or save data.

onResume()

Called if the activity is re-started.

it can be used to initialize fields.

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R. Partha Sarathy

About Dalvik Virtual Machine

• Its Simlarly like Java's JVM(Java Virtual Machine)
• DVM have own bytecode format

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R. Partha Sarathy

Android Application Architecure

Hai friends now we are going to see Android Application Architecture.

AndroidManifest.xml:
                                The Components and Settings of android application are described in this xml file.
This is also contains required permissions.

R.java & Resources:

• It Genertes reference class
• its under "gen" folder
• That resource must be defined under "res" folder. like image etc..
• if we create new resource its automatically generated in R.java file.

Assests:

• Its Structured Value.
• Its used to store any type of data.
• we can access this via AssetsManager

Activities & Layouts:

• The activity is defined via Layout
• The Activity include widgets
• The layout can be declared via xml or java code. (mostly we use xml)
• It Specified at res/layout folder(main.xml)
• we can use View id

                             

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R. Partha Sarathy

Overview of Android Programming Development Process

Hai friends now i am going to share about Android Development Process.
I think below image will explain the process.

• Android programming is written by Java code. the Java source code converted into .class file by using Java Compiler.
• Android Provides tool "dx". It converts Java class file into dex
• All class files are converted and compressed into one application. which is in dex format.
• During conversion of .dex the reduent information has been optimized.
• So its very smaller then smaller.
• The dex file and resource of android packed into .apk(Android Package) format.
• This process done by AAPT(Android Asset Package Tool)
• The .apk file contain all detail. This run by ABT(Android Bridge Tool)

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R. Partha Sarathy

What is Android Development Tools (ADT)

Hai friends now we will might discuss about Android Development Tools

• It provides ADT plugins together work with Eclipse IDE
• ADT Contains all required funtions such as create, compile, Debug & Deploy.
• Its Provides Emulator.
• The Emulator used to test our application without real device..

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R. Partha Sarathy

Android Components

Hai friends now we are going to discuss about List of Android Components.

1. Activity
2. Views & View Groups
3. Intents
4. Services
5. Content Provider
6. Broadcast Receiver
7. Widgets (Home Screen)
8. Others

Activity :

• Its Presentation Layer
• Its Simply defined as front Screen.
• It Can Display Dialog
• it may have several Activities.

Views & View Groups :

• Views are User interface Widgets
• Base Class android.View.view.views

View Group:

• Its used to arrange Views.
• Its Layout Manager

Intent:

• Its used to get Some functionality from other applications
• Application has to register them self intents via IntentFilter

Services:

• Its Perform background task without provide user interface

Content Provider:

• Its Structure Interface to application data.
• The user can share data with other applications.
• SQLite database uses Content Provider.

Broadcast Receiver:

• Its used to receive System messages & Intents

Widgets:

• Widgets are Interactive components.
• Its display some data the user perform some task via that. for example Email Reading

Others:

 Live Folder and Live Wall Papers.

     

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R. Partha Sarathy

Android Security and Permissions

Hai Android Coders now i am going to share about Security Features of Android

• During Deployment on Android Application. it will create unique Id and User for Android Application.
• Other Android Applications cannot access these files.
• Normally Android application starts with it own process.
• If data to be share the application must do via Service or Content Provider.
• It have Permission System.
• It have some predefined permission but we have to define some additional permission for our application.
• These permissions have different levels. Some Permissions granted by android System. like Internet State permission. Some Permission may granted by User like internet Access permission.
• The User may reject user permission.
• In Most cases the requested permission will be present before install Application. The User will decide about permission.

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R. Partha Sarathy

What is Google Play or Android Market

A brief Notes about Google Play :

• Its an Application. Its used to install android application into mobile.
• All Android Mobiles having Google Play Service. 
• Its also notify updates for already existed applications.

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R. Partha Sarathy

Advantages and Disadvantages of Android

Hai friends Now i am going to share about advantages and disadvantages of Android. 

Advantages :

• Allows Background Processing
• Provides Rich User Interface
• Supports 2D & 3D Graphics
• Access the File System
• Using SQLite Database
• It Can reuse already existed Applications

Disadvantages:

• It will not support for .avi and .gif format files
• It takes only Java Syntax but provide own library files.

Difference Between Apple IOS and Android

Hai Friends here i am going to share the difference between Apple IOS and Android..
The IOS is a Competitor of Android.

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R. Partha Sarathy

List Of Android OS Versions

Hai Friends Here i am going to share about versions of Android.

About Android

Its Mobile Operating System based on Linux OS and Java Programming.

Android OS:

                  Its not only Operating System. it includes many extra features..

Android Programming: 

                                Android Programming inherits the concepts from Java Programming. So Java Programmers easily can develop android apps. Android Program also have own separate concepts.

Android SDK- Android Software Development Kit:

                       It Provides all necessary tools to develop android application such as Compiler, Debugger, Device Emulator and have own Virtual Machine (DVM- Dalvik Virtual Machine).

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R. Partha Sarathy

History of Android

A brief History of Android:

Actually Android is small software company. they developed mobile oriented applications for their clients. In 2005 the Google bought Android Company for such amount. They Formed OHA (Open Handset Alliance) for Android OS Development. 

There are 34 members for OHA. Members like Motorola  Sony Ericsson  t-mobile etc. .Finally Google released First android G-mobile in 2008.

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R. Partha Sarathy