An‘do-it-yourself’droid

Praveen Kumar Pendyala

Outline• Brief intro to the Droiddevelopement

• Setting up the Life saviors - Development tools

• ‘Hello Droid’ application

• Application structure

• Intelligence and beauty – Java code and UI (XMLs)

• Our best pals – APIs, In-built libraries

• Group chat app UI and Java code OnclickListeners Intents Multithreading Network actions Changing views from Java code Permissions

• Exporting and signing your application

• Web app code

Intro• Why Android ?

Intro• Android versions and

StatsVersion Codename API Distribution

1.6 Donut 4 0.2%

2.1 Eclair 7 2.4%

2.2 Froyo 8 9.0%

2.3 - 2.3.2

Gingerbread

9 0.2%

2.3.3 - 2.3.7 10 47.4%

3.1Honeycomb

12 0.4%

3.2 13 1.1%

4.0.3 - 4.0.4Ice Cream Sandwich 15 29.1%

4.1Jelly Bean

16 9.0%

4.2 17 1.2%

5.0 ? Key lime pie ? -

Development tools - Intro• Eclipse

Requires Java Runtime Environment (JRE) Like an advanced notepad/Gedit you used for C/C++ A general development tool for Java programming (not limited to

android)

• Android SDK Contains the necessary tools to create, compile and package

Android application

• ADT (Android Development Tools) A set of components (plug-ins) which extend the Eclipse IDE with

Android development capabilities

Development tools - setup• JRE

• Run and install the JRE software that came with your bundle

• What about Eclipse, ADT, Android SDK ?• Lucky you are…• Google now bundled everything and gives you as a package which

can be used directly after JRE installation ! (You may not appreciate this, as you haven’t been through earlier setup process)

‘Hello Droid’ applicationIn eclipse,1. File New Android Application Project (or) File New other Android Android

Application Project

‘Hello Droid’ application

Enter these valuesApplication Name : HelloDroidProject Name : HelloDroidPackage Name : com.myfirstapp.hellodroid

Website of your application in reverse

Press Next twice………………..

‘Hello Droid’ application

Play with the Names, Images and Shapes. I suggest, you select your fav pic, for feel

Press Next twice again…..(Yeah you have to select BlankActivity)

‘Hello Droid’ application

Leave the values as they are for this session

Finish……

Simple…..Isn’t it ??

Application structure

All Java code

All images used

The UI design elements

All the words you see in the app and colors that appear

Your application details-Name, What should come 1st, Version, Services used-Permissions that are needed, Activities(IMPORTANT !!)

Manifest.xml

This is what gives an Idea of what your application is, what it uses and ….What not ? Almost every info

Strings and colors

UI design

Java code, Libraries, APIs

API – Application Program Interface

Groupchat application - UI

<app> res layout activity_main.xml

Groupchat application - Strings<app> res values strings.xml

Groupchat application – OnclickListeners & Intents

<app> src MainActivity.java

Now lets setup an action for our button. Going to a new screen on click

Groupchat application – Creating new XMLs and classes

Lets now create an Activity and corresponding Layout XML for messaging

1. Goto <app> res layout• Right click on layout New Android XML file Name it ‘messaging.xml’ and

finish

2. Goto <app> src com.<packagename>• Right click on package New Class Name it ‘Messaging’ and finish

Groupchat application – More on UI

<app> res layout messaging.xml

Add these two as childs to the main LinearLayout

Groupchat application – Starting threads

<app> src <package> Messaging.java

Lets receive the Nick and do some settings

Groupchat application – Multithreading<app> src <package> Messaging.java

• Network activity always on a background thread

• No UI changes in this thread !! (IMP)

Groupchat application – Network data reception

<app> src <package> Messaging.java

<app> src <package> Messaging.javaGroupchat application – Network data sending

Groupchat application – Changing views from Java code

<app> src <package> Messaging.java

Groupchat application – Extras (Special characters support)

<app> src <package> Messaging.java

Groupchat application – Activities, Permissions<app> src <package> Messaging.java

• Is that it ? Will it work ? Of course not….

Add Internet permission

Declare your class as an activity

Groupchat application – Ready to go….<app> src <package> Messaging.java

Just seconds away to see it live….

• In package explorer Click on your project Click Run Android application Select your device (or) Start emulator

• Problem ?? Device not detected ??• Just explore to the ‘bin’ folder in your application.• Copy and transfer <app>.apk file to your device

Export and signing your application

• By default when you press run apps are signed using debug key• Debug key signed apps not allowed in the market

• To Export your application for publishing in Android market• File Export Android (Export And…) Create a Keystroke

Create an alias Save the apk Finish

Groupchat application – Web endputData.php

This is just the beginning ...

I look forward to see awesome apps from you all…Please do keep me posted if you make an app in future

Hope you all enjoyed

Thank you