A Lap Around Android IBen Monro

June 26, 2010SoCalCodeCamp

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Overview

Platform Overview The Emulator & DDMS Hands on walk through

Activities UI Components Intents Resources Dialogs

Questions & Answers

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Android: The platform

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Applications in Android

Written in Java Bundled into APK packages that include:

Compiled Java code Data, files & other resources required for the application to

install & run Runs in its own isolated process & java VM. Have a manifest file that defines the way the OS Launches

& interacts with the Application. Components of an Android App:

Activities Services Broadcast Receivers Content Providers – Activated by Content Resolver Intents are Asynchronous system messages that tell the OS

when/how to do something.

Activated by “Intents”

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Activities

Activities are the core of Android App UIs. Made up of Views & View Groups (aka Layouts)

Examples of Views:▪ TextView / EditText▪ ListView / GridView▪ Gallery▪ Spinner▪ Button▪ ImageView▪ DatePicker

Layouts:▪ LinearLayout▪ RelativeLayout▪ TableLayout▪ AbsoluteLayout▪ Frame Layout▪ TabHost*

Can launch other Activities, Services & Broadcast Events

Built using XML, code or Both Supports Styles, Themes, Localization etc.

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Android Services

Services are processes that run in the background.

Not much unlike a windows service. Can be used to play music, communicate

with a server, perform long running processes etc.

Typically used to trigger notifications in the status bar.

Communication (IPC) can be done using AIDL – Android Interface Definition Language.

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Broadcast Receivers

Receive and react to broadcast announcements from the OS

No UI, but they may trigger an Activity

Examples: Time-zone has changed Battery is low Picture has been taken User has changed a system

preference

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Content Providers

Provide clean way for your application to expose its data to other applications on the device and visa versa.

Data can be stored in any way you want, Files, Preferences, SQL Lite DB or whatever other resource you need.

Content can be audio, video, images, contact information, etc.

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Home Screen Widgets

A small “slice” of an application that runs on the application home screen.

Limited functionality & set of Views/Layouts can be used.

Good for displaying things like stock tickers, status updates, weather forecasts, news headlines, etc.

Allows users to see a key piece of your app, without having to leave their home screen.

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Killer Development Environment

What you’ll need to create Android Apps: Java Development Kit (JDK) 6 Eclipse▪ Spring Tool Suite with Google (

http://www.springsource.com/products/springsource-google-download

)▪ Eclipse Classic 3.5 or greater will also work

Android SDK Android Development Tools (ADT) – eclipse

plug-in for Android development.

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Creating an Android Project in Eclipse File New Android Project

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Project Structure

• Source Code Directory• UI Layout Directory (XML) – validated by compiler w/ detailed error

messages• Application Manifest – tells OS how to interact w/ your app.• Icons / Graphics – can be bitmap or xml based• Strings / Styles / Themes

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The Flow of an Activity

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Demo time

Lets build a calculator!

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Resources

Main Android Dev Site: http://developer.android.com

Stack overflow: http://stackoverflow.com/questions/tagged/android

Google I/O Talks: http://www.youtube.com/googledevelopers

Tutorials & Forums: http://www.anddev.org/ http://www.androidpeople.com/ http://www.androidcentral.com/

Building Android Apps with Hudson & Ant: http://www.facebook.com/note.php?note_id=499519

075367

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Q&A

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