Ii 1300-java essentials for android

Java Essentials for Android

Presented by

Adrian Mikeliunas

[email protected]

TASKMobileSolutions.com

mailto:[email protected]


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MoDevAcademy

MoDevAcademy will offer professional training across platforms that include beginner, intermediate and advanced courses.

The format will be one day courses that can be taken individually or paired for a multi-day experience. The Academy intended to fill a much needed void in the market for in-depth mobile developer training.

Upcoming Classes

Schedule:

• January 22nd: Starting up with iOS Development

• January 23rd: Expert Objective-C

• January 24th: Advanced Xcode Development

Register at MoDevAcademy.com/Registration

Online Resources

The references in this presentation, and many other resources are available at:

http://Gomodev.com/MoDevAcademyResources


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Agenda

Java Similarities

Java Differences

Android Programming with Java in Eclipse

Resources Google Samples F-droid.org SourceFourge.net


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Android & Java ComparisonsSimilarities

Differences


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Android <> Java

Android is Google’s Operating System, combining Linux with their own version of Java, named Dalvik

Dalvik uses a subset of Harmony, an Apache Software Foundation project

Dalvik is open-source software. Is the name of a fishing village in Iceland

http://en.wikipedia.org/wiki/Dalvik_virtual_machine


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Android/Java Similarities

Android uses Java syntax

Android uses similar APIs

Android, supports a relatively large subset of the Java Standard Edition 5.0 library

Java files on Android are compiled into .class files and then in dalvik executables(.dex)

java.io - File and stream I/Ojava.lang - Language & exceptionsupportjava.math - Big numbers, rounding, precisionjava.net - Network I/O, URLs, socketsjava.nio - File and channel I/Ojava.security - Authorization, certificates, public keysjava.sql - Database interfacesjava.text - Formatting, natural language, collation…


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Android/Java Differences

Unlike Java VMs, which are stack machines, the Dalvik VM uses a register-based architecture

Dalvik does not align to Java SE nor Java ME class library profiles

Java is a programming language, while Android is a mobile phone platform


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Android/Java Differences

Android does not use the Abstract Window Toolkit nor the Swing library. User Interface is built using View objects

Android layout behavior is encoded in the containers using XML files, unlike Java where Layout managers can be applied to any container widget

Android relies on a master AndroidManifest.xml file There is no Main class You need to define default activity here THIS IS A MANUAL METHOD


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Android & EclipseSetup

Components

Development

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Android Development Setup - 1

Your Development Computer Install Java Development Kit (JDK)

www.oracle.com/technetwork/Java/javase/downloads/index.html

Install Eclipse Classic version www.eclipse.org/downloads

Requirements: Windows, Mac, or Linux

developer.android.com/sdk/requirements.html


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JDK

www.oracle.com/technetwork/Java/javase/downloads/index.html

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Eclipse

www.eclipse.org/downloads

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Android Development Setup - 2 Downloading the SDK Starter Package

Install Android SDK http://developer.android.com/sdk/index.html

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Android SDK Manager

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Android Development Setup – 3a

ADT Plugin for Eclipse Start Eclipse Select Help > Install New Software.... Click Add, in the top-right corner

In the Add Repository dialog that appears, enter "ADT Plugin" for the Name Location:

https://dl-ssl.google.com/android/eclipse/

Click OK.


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Android Development Setup – 3b

ADT Plugin for Eclipse In the Available Software dialog, select the

checkbox next to Developer Tools and click Next. In the next window, you'll see a list of the tools to

be downloaded. Click Next. Read and accept the license agreements, then

click Finish.

When the installation completes, Restart Eclipse!


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Android Development Setup – 3c

Select Window > Preferences...

Select Android from the left panel You may see a dialog asking whether you want to send

usage statistics to Google. If so, make your choice and click Proceed. You cannot continue with this procedure until you click Proceed.

For the SDK Location in the main panel, click Browse... & locate your downloaded SDK directory

Click Apply, then OK

http://developer.android.com/sdk/eclipse-adt.html#installing


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Android Development Tools (ADT)

The Android SDK includes several tools & utilities to help you create, test, & debug your projects

ADT plug-in conveniently incorporates most of these tools into the Eclipse IDE, where you can access them from the DDMS perspective


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ADT Inventory

The Android Emulator

Dalvik Debug Monitoring Service (DDMS)

Android Asset Packaging Tool (AAPT)

Android Debug Bridge (ADB)


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ADT Inventory-2

The following additional tools are also available:

SQLite3 A database tool

Traceview Graphical analysis tool

MkSDCard

dx: java bytecode to Dalvik executable

activityCreator Script


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Android SDK

android.jar

Documentation

Samples directory

Tools directory

usb_driver


• Eclipse Navigation

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• Package Explorer

• Code Editor• Outline View

• Eclipse Tools-DDMS

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Dalvik Debug Monitor Service


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Android Emulator

Create an Android Virtual Device

Run it!


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Android Architecture

Applications

Application framework

Libraries

Android Runtime (Dalvik VM)

Linux 2.6 Kernel

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Android Layers

Linux kernel provides drivers for the Android hardware, networking, file system access & inter-process-communication

Libraries are mostly written in C or C++

Core Libraries are the core development kit including utility, i.o. etc

Dalvik Virtual Machine is an optimized Java VM

Application Framework is the API to developers

Applications are user facing programs


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Android Applications

• Each application runs in its own process, gets unique identifier & runs its own instance of Dalvik VM

This way the processes are isolated & crash of one application does not bring down the whole system!


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Android Programming

System Level – modifying the Android system code & adapting it to various hardware platforms. It also involves creating additional services & features in the android system itself. C. C++

Application level – creating software products & services which sits on top of the Android software stack & interacts with the hardware through the underlying Android platform. Java.


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Application Development Basics

Activity Presents visual interface to the user Each activity has a separate window to draw the visual component but if required it can

use more than one window also

Services runs in the background and carries out some

background process while the other visual component s are running in the foreground


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Application Development Basics-2

Broadcast receivers responsible for receiving and reacting to broadcasted

messages

Content providers This provides specific set of data from one application to

other applications. Used in conjunction with Content resolver which provide methods for inter process communication

Widgets These are programs anchored to the home screen

providing information updated fairly frequently

Android ActivitiesEach Android application must designate a default activity within the Android manifest file

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Android Activity ClassThe Activity base class defines a series of events that governs the life cycle of an

activity:

onCreate() — Called when the activity is first created

onStart() — Called when the activity becomes visible to the user

onResume() —when the activity starts interacting with the user

onPause() —current activity is being paused & the previous activity is being resumed

onStop() —when the activity is no longer visible to the user

onDestroy() — Called before the activity is destroyed by the system (either manually or by the system to conserve memory)

onRestart() —when the activity has been stopped & is restarting

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Android Activity Class (2)

public void onStart(){super.onStart();Log.d(tag, “In the onStart() event”);}

public void onRestart(){super.onRestart();Log.d(tag, “In the onRestart() event”);}

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Android Activities To create an activity, you create a Java class that

extends the Activity base class:

package com.example.Activities;

import android.app.Activity;

import android.os.Bundle;

public class MainActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

}

}

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Android Activities-2

Your activity class would then load its UI component using the XML file defined in your res/layout folder. In this example, you would load the UI from the main.xml file:setContentView(R.layout.main);

Every activity you have in your application must be declared in your AndroidManifest.xml file

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Android Activities (3)<?xml version=”1.0” encoding=”utf-8”?><manifest xmlns:android=”http://schemas.android.com/apk/res/android” package=”com.example.Activities” android:versionCode=”1” android:versionName=”1.0”> <application android:icon=”@drawable/icon”

android:label=”@string/app_name”><activity android:name=”.MainActivity”

android:label=”@string/app_name”><intent-filter><action android:name=”android.intent.action.MAIN” /><categoryandroid:name=”android.intent.category.LAUNCHER” /></intent-filter>

</activity> </application> <uses-sdk android:minSdkVersion=”9” /></manifest>

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Android Layouts

An Android layout is a class that handles arranging the way its children appear on the screen Anything that is a View (or inherits from View) can be a

child of a layout

All of the layouts inherit from ViewGroup (which inherits from View) so you can nest layouts You could also create your own custom layout by making

a class that inherits from ViewGroup

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The Android Layouts are:

AbsoluteLayout

FrameLayout

LinearLayout

RelativeLayout

TableLayout


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Android Resources

Google Samples

F-droid.org

sourceforge.net


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Example: Timesheet

Timesheet is an application designed primarily for contractors and freelancers to track the time spent on different tasks. http://tastycactus.com/projects/timesheet/

f-droid.org/repository/browse/?fdfilter=timesheet&fdid=com.tastycactus.timesheetplay.google.com/store/apps/details?id=com.tastycactus.timesheet


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Q& A

Ii 1300-java essentials for android

Technology

java java

java essentials

androidandroid java

version of java

java syntax support

java se

java vms

library java files