JavaME + Android in action
Java Platforms for Mobility
CEJUG CCT
Coffee with Tapioca, December 2008
Vando Batista
Some Rights Reserved

Objectivity
Introduce the Java development platforms for
mobile devices,
JavaME and Android, performing
implementations activities for each one, in a
lab-style practice, with some APIs
Target audience: Java developers interested on
Mobile Platforms

Agenda
• Overview on Mobile Platforms
• Java ME in action
• Android in action
• Challenge

After this course you will…
• identify mobile platforms characteristics
• understand how to implement a JavaME
application
• understand how to implement a Android
application
• have implemented, at least, one application
for each platform
• maybe… win a book: Free Software and Digital
Inclusion (in Portuguese)

Applications…
• Location Based Systems
• m-commerce, collaboration, marketing
• Mobile Social Networks
• Military
• Search and safety
On the move apps
Improve user experience

Users: mobile vs. desktop
• India: Many more mobile than desktop Web users (4 to 1),
The Economic Times, Oct 2007

Motivation
• Evolution, popularization
– Device resources
– Connectivity
• Business applications for mobile devices
– Growing 102% per year, until 2012 - Mobile
Business Applications and Services, ABI Research
• New services, new opportunities

Mobile Ecosystem
Source: SDN - java.sun.com/javame

Mobile, Portable Devices

Mobile Networks
3G, 4G...

Development Platforms

Mobile Computing
“Computing that deals with connection
exploration on mobile devices”
Coulouris, Dellimore, Kindberg. Distributed Systems (4th edition)
Mobility transparency
allows the movement of resources and clients
within a system without affecting the
operation of users or programs. Two flavours:
migration and relocation

\"small is the better\"
• Challenges
– Devices
– Networks
– Limitations and heterogeneity
• Dependencies
– Power: battery autonomy
– Resource: connection availability
“Remember that there is no code faster than no
code” Taligent‘s Guide to Designing Programs

Mobile Development
• Software Development Kit (SDK)
– Emulator, Documentation, Tools, Services, etc.
• Integrated Development Environment (IDE)
• IDE Plugins

Are you ready?
Set your
environments!
http://www.cejug.org/display/cejug/Ambiente+para+os+mini-
cursos+de+JavaME+e+Android

Welcome to the…
JavaME
Development

Introduction
• Java Platform, Micro Edition
– Java Community Process (JCP) based
– Java Specification Request (JSR)
• Reference Implementation (RI)
• Test Compatibility Kit (TCK)
• Proprietary APIs
• Native Applications
• Since 2000
• 80% handsets: 1.2bi phones, 1200 models,
180 carriers

Architecture
• JVM, KVM
Source: SDN - java.sun.com/javame

Core APIs
• Configuration
– CLDC, CDC, BD-J
• Profile
– MIDP, IM, PP, PBP, FP
• Umbrella
– Fragmentation: Computational, Physical,
Functional
– JTWI, MSA (Full, Subset)

Development Infrastructure
• Many environments: handset dependency
• For this lab:
– SDK: Sun WTK 2.5.2, JME SDK 3.0
– IDE: Eclipse Ganymede (3.4)
– Plugin: Mobile Tools for Java 0.9
• Unified Emulator Interface (UEI)

Hello JavaME World!
• build, obfuscate, preverify, run, debug, and
deploy
• Create a project
• Project structure
• Create a MIDlet
– javax.microedition.midlet.MIDlet
• Over the Air (OTA) / installation
• On Device Deployment/Debug
• MIDlet.this.platformRequest(“tel:*”)

MIDlet Lifecycle
• Application Management Software (AMS)
– Java Application Manager (JAM)
• notifyDestroyed()
• notifyPaused()
• resumeRequest()

MIDlet Lifecycle
Coding
import javax.microedition.midlet.MIDlet;
public class HelloWorld extends MIDlet {
public HelloWorld() {
System.out.println(“MIDlet constructor\");
}
protected void destroyApp(boolean arg0) {
System.out.println(\" MIDlet destroyApp()\");
}
protected void pauseApp() {
System.out.println(\" MIDlet pauseApp()\");
}
protected void startApp() {
System.out.println(\" MIDlet startApp()\");
}
}

Application Packaging
• Profile dependent
• MIDlet Suite
– Java ARchive (.JAR)
– Java Application Descriptor (.JAD)
• Package generation

Application Configuration
• Java Application Descriptor (.JAD), Manifest
• MIDlets
• Permissions
• Properties:
– System
System.getProperty(“javax.microedition.*”)
– Application
MIDlet.this.getAppProperty(\"propertyName\")

Code Optimization
• Free objects
• String Vs. StringBuffer
• Arrays Vs. Collection
• Moderate use
– Synchronized
– Instance variables
– Parameter number
– Resources initiation
– Interfaces, internal classes
• JAR obfuscation, compression

GUI
Source: IBM - ibm.com

GUI
Coding
public class HelloWorld extends MIDlet {
private Display display;
private Form myForm;
// initialization on MIDlet constructor
public startApp() {
display = Display.getDisplay(this);
// display.getCurrent();
display.setCurrent(myForm);
}
...
}

Keyboard Handling
• Components
– javax.microedition.lcdui.CommandListener
– javax.microedition.lcdui.Command
• Registration
– setCommandListener(CommandListener l)
• Notification
– commandAction(Command c, Displayable d) {}
• Potential deadlock: operations such as IO and
networking should run on a separate thread

Keyboard Handling
Coding
public class HelloWorld extends MIDlet {
Displayable d = new TextBox(“Title”, “Body”,
20,TextField.ANY);
Command c = new Command(“Exit”, Command.EXIT, 0);
d.addCommand(c);
d.setCommandListener(new CommandListener() {
public void commandAction(Command c, Displayable
s) {
doSomeAction();
}
} );
}

Persistent Storage
• Record Management System (RMS)
– javax.microedition.rms.*
• RecordStore
• RecordEnumeration
• RecordComparator
• RecordFilter

Persistent Storage
Coding
...
RecordStore rs = null;
String value = \"Java ME in action\";
...
try {
rs = RecordStore.openRecordStore(“RecName”, true);
byte[] recData = value.getBytes();
rs.addRecord(recData, 0, recData.length);
String data = new String(rs.getRecord(1));
} catch (Exception e) {
...
}

Connectivity
• Generic Connection Framework (GCF)
– javax.microedition.io.*
• Remote (Infrastructured)
– HTTP, HTTPS
– TCP, UDP
– Wireless Messaging (JSR120, 205)
– Push Registry (MIDP)
– SIP (JSR180)
• Local (Ad hoc)
Source: SDN - java.sun.com/javame
– JABWT (JSR 82)
– Ad Hoc Networking API (JSR 259)

Connectivity
Coding
HttpConnection httpConn = null;
InputStream = null;
try {
httpConn = (HttpConnection)
Connector.open(\"http://www.cejug.org\");
httpConn.setRequestMethod(HttpConnection.GET);
httpConn.setRequestProperty(\"User-Agent\",
\"Profile/MIDP-2.0 Configuration/CLDC 1.1\");
is = httpConn.openInputStream();
int ch = -1;
while((ch = is.read()) != -1){
...
}
…

References
• Mobile and Embedded Guide to JavaOne 2008
– http://wiki.java.net/bin/view/Mobileandembedded/JavaO
ne2008
• A Survey of Java ME Today
– http://developers.sun.com/mobility/getstart/articles/surv
ey/
• Java ME Device Table
– http://developers.sun.com/mobility/device/
• JEDI course (DFJUG)
– http://jedi.wv.com.br

Welcome to the…
Android
Development

Open Handset Alliance
Manufactures
Semiconductors Carriers
Content Software

Introduction
• Software stack
– Operating System
• Linux Kernel (v2.6)
– Middleware
• Services
– Applications
HTC Dream (G1)
• Java
• Dalvik: custom virtual machine for embedded
• Since 2008

Characteristics
• Applications…
– without borders
– are created equal
– can run in parallel
– can easily embed the web
• Open source
– http://source.android.com
• Apache 2.0 and GLP v2 license

Architecture

Basic Components
• Activity
– UI component (Form like) typically corresponding
to one screen
• Intent Receiver
– Set and respond to an external event: notifications
or status changes. Can wake up your app
• Services
– Task without UI that runs in the background
• Content Provider
– Allow applications to share data

Packages
android.util android.telephony
android.os android.hardware
android.graphics
android.text android.net.wifi
android.database android.location
android.content android.media
android.view android.opengl
android.widget
android.app

Development Infrastructure
• Recommended environment
• For this lab:
– SDK: AndroidSDK 1.0
• QEMU-based (system image)
– IDE: Eclipse Ganymede (3.4)
– Plugin: Android Development Tool 0.8, WST
• Add to environment variable PATH
– tools directory
• A lot of XML for application, activity, intent,
layout, view, variable

Hello Android World!
• Create a project
• Create an Activity
– android.app.Activity
• Project structure
• LogCat
• Deployment/Debug

Application Configuration
• AndroidManifest.xml
• Application
– Activity, Intent Filter
• Permissions
<?xml version=\"1.0\" encoding=\"utf-8\"?>
<manifest
xmlns:android=\"http://schemas.android.com/apk/res/android\"
package=\"org.cejug.android\"
android:versionCode=\"1\"
android:versionName=\"1.0.0\"
android:screenOrientation=\"landscape\">
...

Application Anatomy
• Activity
– Can reuse functionality from other components by
making a request in the form of an Intent
– Can be replaced at any time by a new Activity
with an equivalent IntentFilter
• Intent
– Request to do something: move from screen to
screen. Activity.startActivity(myIntent)
• Intent Filter
– Description of Intent types

Application Configuration
...
<application android:icon=\"@drawable/icon\"
android:label=\"@string/app_name\">
<activity android:name=\".HelloActivity\"
android:label=\"@string/app_name\">
<intent-filter>
<action android:name=\"android.intent.action.MAIN\" />
<category android:name=\"android.intent.category.LAUNCHER\" />
</intent-filter>
</activity>
<activity android:name=\".HelloListActivity\"
android:label=\"ListActivity\">
</activity>
</application>
</manifest>

• Activities are
stacked
• Only one is
active
• Only one is
open

Application
Coding
public class HelloActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView tv = new TextView(this);
tv.setText(\"Hello, Android\");
setContentView(tv);
...
}
}
• onStart(), onResume(), onPause(), onStop(),
onRestart(), onDestroy()

SDK Tools
• Emulator
• Dalvik Debug Monitoring System (ddms)
• Android Debug Bridge (adb)
• Android Asset Packaging Tool (aapt)
• Android Interface Description Language (aidl)
• sqlite3
• Traceview
• mksdcard
• dx, activitycreator, and others

Application Packaging/Deployment
• APK file
– .DEX
• Log into a Linux server via a shell
• Installation
– adb install Application.apk
– Uninstall
• adb shell (remove file from /data/app/)

GUI
• Define in: code or XML
• res/layout
• Views
– Text, Edit, List
– Image, Web, Map
• Layouts
– Frame, Linear, Relative, Table, Absolute

res/layout/main.xml - Views
<LinearLayout
xmlns:android=\"http://schemas.android.com/apk/res/android\"
android:orientation=\"horizontal\"
android:layout_width=\"fill_parent\"
android:layout_height=\"wrap_content\"
android:background=\"@drawable/icon\">

res/layout/main.xml - Layouts
<Button android:id=\"@+id/callButton\"
android:layout_width=\"fill_parent\"
android:layout_height=\"wrap_content\"
android:text=\"Show Dialer\" />
<EditText android:id=\"@+id/phoneNumber\"
android:layout_width=\"fill_parent\"
android:layout_height=\"wrap_content\"
/>

Event Handling
Coding
…
final EditText phoneNumber = (EditText)
findViewById(R.id.phoneNumber);
Button callButton = (Button) findViewById(R.id.callButton);
callButton.setOnClickListener(new Button.OnClickListener()
{
public void onClick(View v) {
Intent CallIntent = new Intent(Intent.ACTION_CALL, Uri
.parse(\"tel:\" + “+5585\" + phoneNumber.getText()));
CallIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(CallIntent);
}
});

Emulator: No support for…
• Placing or receiving actual phone calls
• USB connections
• Camera/video capture (input)
• Audio input
• Determining connected state
• Determining battery charge level / AC state
• Bluetooth

References
• Android Documentation
– http://code.google.com/android
• Android A Programmers Guide (Jerome
DiMarzio, Mc Graw Hill)
• Professional Android Application Development
(Reto Meier, Willey Publishing)
• Many sites, forums, videos, screencasts,
presentations…

Would you like to be challenged?
Practice matters!

Challenge Requirements
• Based on our lab practice
• Create an application on JavaME or Android
platform following the requirement
– Receive a user text input through a wizard

Questions & Answers

Thank you!
Vando Batista
vandofb at gmail.com
msn: vfbatista at hotmail.com
skype: vfbatista