One day Crash Course in Java ME Development. by Michael Sharon, Co-founder/CTO, Socialight

Transcription

1 One day Crash Course in Java ME Development by Michael Sharon, Co-founder/CTO, Socialight

2 sources: Platform Language Cost Learning Curve Emulator Availability Java ME Java FREE Average Free ~1.5bn Flash Lite AS Varies Average With IDE m Symbian C++ FREE STEEP! Free 120m.NET C#, C++, VB.NET $$$$ STEEP! IDE 4.5m BREW C++ $$$$ STEEP! Simulator???? Python Python FREE Gentle Add-on Nokia-only WAP / Mobile Web XHTML, WML FREE Gentle Free 2bn+

3 Java ME (J2ME)

4 Java ME / J2ME Java ME (formerly known as Java 2 Platform, Micro Edition or J2ME), is a collection of Java APIs for developing software on resource constrained devices such as PDAs, cell phones and other consumer appliances.

5 Java Sources Java Community Process - JSR specification requests reference implementations Sun - SDK, tools, community Manufacturer SDKs, community, device emulators

6 Java VM Other Apps Virtual Machine (KVM) Native Apps Operating System Hardware

7 A typical Java ME stack 1. Configurations - specifies minimum Java technology that we can expect for certain devices - Includes language, virtual machine features, core libraries 2. Profiles - layer defining APIs and specifications for a particular device or market - MIDP, FP - MIDlets 3. Optional Packages - includes additional functionality only supported by certain devices - e.g. Bluetooth API, Location API

8 1. Configurations: CLDC Connected Limited Device Configuration - specifies environment for mobile phone, pagers k of memory for Java - limited power / batteries - intermittent, low-bandwidth connectivity CLDC May 2000, JSR 30 - java.lang CLDC Dec 2002, JSR adds floating point support - bug fixes

9 2. Profiles: MIDP Mobile Information Device Profile MIDP December 2000, JSR 37 - java.microedition.midlet - java.microedition.rms - java.microedition.lcdui - java.microedition.io.httpconnection MIDP Nov 2002, JSR java.microedition.media - java.microedition.lcdui.game MIDP Q3 2006? No! Sometime

10 3. Optional Packages Bluetooth API (JSR 82) - communication with Bluetooth devices Wireless Messaging API (JSR 120, JSR 205) - SMS, MMS, multi-part messages Mobile Media API (JSR 135) - audio, video and multimedia Location API (JSR 179) - interface to location services

11 MIDP 3.0 AKA The Future Background MIDlets (remember TSRs?) Drawing to secondary displays Improved large screen support Auto-start MIDlets And much more... to forget about for the moment

12 MIDlets MIDlets are like Java applets for mobile devices. Has a lifecycle with four stages, created, started, paused, destroyed.

13 The Not-So-Secret Lives of MIDlets START PAUSED destroyapp() pauseapp() startapp() DESTROYED RUNNING destroyapp()

14 Your phone

15 Status Bar Viewport Soft key labels

16 Call Button (select, fire) Soft keys Hang up (suspend app) Joystick - 4 way - center fire/ select Menu button

17 Lightning tour of Java ME * NOT TO BE CONFUSED WITH AN ACTUAL PROGRAMMING COURSE

18 Java ME, classes, objects Object oriented language Multi-threaded Object is an instance of a class Object inherits/extends/implements from single class Methods accessed using dot notation Reveal the MIDP Reference docs

19 Sample Mobile Development Process What? How? Your idea Why? Pick one!! NB!!! Where? Who? Is this possible? Platforms Wireframes / IA Development Deployment Debugging Testing

20 Development Use IDE (Eclipse, Netbeans etc), Java Wireless Toolkit, Manufacturer SDK Create.java files Compile & preverify into.class files Create packaged MIDlet suite Run in emulator / deploy live

21 Packaging MIDlets Java Application Descriptor (JAD) - describes MIDlet suite - specifies name, icon, MIDlets, permissions Java Archives (JARs) - glorified zip file - contains class files, resources - contains MANIFEST.MF MIDlet Suite = 1 JAD file + 1 JAR file AMS - application management software

22 Tips n tricks: JAD Edition

23 Check The Details

24

25

26 Optional extras

27

28

29 Debugging

30 Tips Use System.out.println to print out to console What works in the emulator MAY NOT work identically on phone Emulator runs code much faster than device

31 Testing

32 Tips Do a quick check for known issues in MIDP on device Test in the emulator & device Multimedia applications which use camera, video etc, MUST be tested on device

33 Deployment!!!!

34 Deployment/Provisioning AKA getting it on the phone Over the Air (OTA) Web / WAP / Carrier Deck JAD file specifies location Create.htaccess, MIME-Types Bluetooth (OS X, Windows) Easy, quick installation USB cable expensive, sometimes difficult to obtain Web based - MPowerplayer, ME4SE

35 Tips n tricks: Deployment Bluetooth Drag + Drop on OS X OTA - upload to a server the URL [phone_number]@carrier_ _host.com Get list here:

36 Exercise 1 Create a HelloWorld-type application Run it in the emulator Deploy it to your phone Ensure it runs successfully Extra credit: add an icon

37 Part Deux

38 MIDlet UI 2 main options Abstraction High level classes, Screens (Alert, List, Form, Textbox) Discovery Low level classes - Canvas, GameCanvas javax.microedition.lcdui +.game

39 High Level Low Level Displayable Canvas GameCanvas Screen Alert List Form Textbox

40 Display & Displayable Display manages the screen Display d = Display.getDisplay(this); Displayable is shown on the display Like Easel & Canvas OR Frame & Painting Flexible event handling with Commands and CommandListener

41 Screens (Form, Alert,List, Textbox) Higher-level Standard widgets Implementation dependent Less control over UI Event handling via Commands

42 Canvases Low-level Discovery Key level event handling More control over UI Animation

43 TOP LEFT TOP HCENTER TOP RIGHT VCENTER LEFT VCENTER HCENTER VCENTER RIGHT BOTTOM LEFT BOTTOM HCENTER BOTTOM RIGHT

44 Quick recap

45 The Not-So-Secret Lives of MIDlets START PAUSED destroyapp() pauseapp() startapp() DESTROYED RUNNING destroyapp()

46 OR

47 A MIDlet s Life 1. Show a Displayable 2. Wait for input 3. Do something, then show next screen 4. Lather, rinse, repeat.

48 Idea = Zombie Detector Platform = Nokia N80 Wireframes / IA START DETECT RESULT Zombie Detector IA v0.1

49 Forms-A-Go-Go

50 TastingCanvas

51 Exercise 2 Write a multi-screen application that takes some input from the user, uses it and returns some type of response. Run it in the emulator Deploy it to your phone and run successfully Extra credit: make an animation!

52 Tips n tricks: Graphics edition

53 Images/Icons PNG Lossless competitor to GIF Supports >256 colours and alpha Only use indexed images! 8-bit or 4-bit Some support for transparency

54 Resolutions Nokia Series 60 3rd Edition = 352x216 - definitely not traditional Dual portrait + landscape modes

55 Resolutions 176w x variable height (mostly 208px) = current standard Portrait orientation Nokia Series 60 2nd Edition, Motorola RAZR, ROKR, PEBL, iden, Sony Ericsson 128w x variable height Old standard 96x - even older, painful to resize artwork

56 Tools Photoshop / Gimp / Pixel Debabelizer PNGCrush, PNGOut, TweakPNG Icon Studio

57 Part Three

58 Exceptions What are exceptions? an event that occurs in a program that disrupts the normal flow of operations Use try, catch, finally to handle 2 - Errors - serious errors 1 - Checked exceptions - IllegalArgumentException 3 - Runtime exception - NullPointerException

59 Why we love Exceptions Separate error handling code Aids in debugging Grouping and differentiating error types

60 Threads What are threads? Single sequential flow of control AKA sub processes which will do things for you Application = System thread + other threads J2ME is multithreaded

61 Threads (2) Every thread has a context Running thread is executing code Ready thread is ready to execute code Suspended thread is waiting on an external event. Terminated thread has finished executing code. Threads are scheduled (usually by OS)

62 Unthreaded MIDlet startapp() showmenu() dosomething() showmenu() System Thread Other process

63 Threaded MIDlet startapp() showmenu() dosomethingthread() showmenu() System Thread Other process

64 Threads (3) To use threads you need: 1. an instance of java.lang.thread 2. an object that implements java.lang.runnable

65 Using Threads public class DoSomething implements Runnable { public void run(){ // here is where you do something } } DoSomething doit = new DoSomething(); Thread mythread = new Thread( doit ); mythread.start();

66 Multimedia

67 MMAPI (JSR-135) MIDP 2.0 Audio playback / record Video playback / record Vibration

68 MMAPI Architecture,$-$.#"!"#$%#& '#(#)*+&,% &'(()*#& +$%$!"#$%& ("/0*+#&!/-%"/)& / -*.(&*"! "*-%$.!/0!11234!+$,5*6.,6%$.!!*7!+!,8+77!9*65!#:8;!76+6*,!&.65#<7=!+>>8*,+6*#:7!,+::#6!,$.+6.!+:

69 Player State Model /"#$$0,#+"'(!"#$%&'($)!"#$%&"'( #$%&'($),$0."'(,$0."'( /"#$$0,#+"'( )!"*"+,-'( -&0/$) *#$+$,-.$),$0."'(.+0)'( 0!1"2/ 0*13"/%#.+#!+'( /,%#,$),$0."'(!

70 MMAPI Usage Check device support(stage 1) Check Content-Type Audio - sampled files large MIDI small

71 MMAPI Camera Capture video (mostly stills) Draw to Form / Screen Create thumbnails Interesting applications Attack of the Killer Virus

72 Networking! (the good kind)

73 GCF Generic Connection Framework lives in javax.microedition.io HTTP required in MIDP 2.0

74 Partial GCF Diagram Connection InputConnection OutputConnection StreamConnection CommConnection ContentConnection HttpConnection HttpsConnection

75 HTTP Powers the dubdubdub AKA the Interweb Stateless protocol Required in MIDP 2.0

76 OPERATION: HTTP Requests + Responses GET, HEAD, POST HEAD - only headers get returned POST - parameters passed in body GET - parameters in URL (query string)

77 HTTP Gotchas POST is more complex Affects MIDlet Security Set Permissions Costs $$ [except for WiFi on N80 :-) ] javax.microedition.io.connector.http (and friends)

78 Exercise 3 Create a simple MIDlet which uses user input and (possibly) HTTP GET to return a useful response Run in the emulator Deploy it to your phone and run successfully Extra credit: display something crazy!

79 HTTP Part Deux: XML

80 XML parsing Use existing libraries kxml - NanoXML - Import libraries into code - /lib folder

81

82 Download & import kxml

83

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85 Export for emulation

86

87 Exercise 4 Create a MIDlet which consumes a data feed in an interesting way Run it in the emulator Deploy it to your phone and run successfully Extra credit: use pipes.yahoo.com

88 Optional topic: Games

89 Where Am I?

90 Finding yourself Many many ways Read Chris Heathcote s etech presentation 35 Ways to find your location A few more than that these days Location API (JSR-179) javax.microedition.location

91 Locating mobile devices GSM positioning OTD - Observer Time Difference EOTD - Enhanced - OTD TDOA - Time Difference of Arrival GPS / AGPS - Global Positioning System Galileo (soon)

92 Location + web Geocoding - via Yahoo!, Google, Ask.com, geocoder.us Reverse geocoding (via Autodesk, ESRI et al) TIGER / Line data Other GIS services

93 US Options Nextel / Boost (iden network) MIDP A-GPS Verizon BREW = boo! Cingular / T-Mobile = Bluetooth GPS (for now) J2ME access to the GPS device (for free!!)

94 iden SDK + GPS Demo

95 Obfuscation in da Nation

96 Obfuscation AKA bytecode obfuscator What is it? Software build tool What does it do? Reduces the size of your class files Makes it difficult to decompile your code Removes unused/unnecessary methods

97 Shrink, optimize, obfuscate Detect and remove unused classes, fields, methods, and attributes. Optimize bytecode and remove unused instructions. Rename the remaining classes, fields, and methods using short meaningless names. Resulting jars are smaller and harder to reverse-engineer. *(thanks Proguard docs!)

98 Smaller JAR files = reduced storage requirements = faster downloading of your application = faster loading & smaller memory footprints

99 3 Obfuscators Proguard Retroguard Jode

100 Exercise 5 Create a fun little game OR create a MIDlet which you would use every single day Run it in the emulator Deploy it to your phone and run successfully Extra credit: add a splashscreen!

101 Bluetooth

102 What is Bluetooth? Short range wireless networking Operates in the 2.45Ghz ISM band Named after a swedish King - Harald Blatand Cable replacement / short range serial Personal Area Network (PAN) piconet - 1 master + 7 slaves

103 Bluetooth Info 1 billion BT devices More than 5 million ways to use it?? (from the Bluetooth.org site) Bluetooth = 1Mbit/s - only 720kb for user applications Bluetooth 2.0 supports EDR (Enhanced Data Rate) allows for up to 3Mb of raw data (2.1 Mb for your apps) Much lower in practice ~ 100kb/s

104 Bluetooth - JSR 82 Java API for Bluetooth Wireless Technology Consists of two separate APIs 1. Java API for Bluetooth Communications via BT radio 2. Java API for OBEX The OBEX protocol Optional API

105 Bluetooth Implementation Java API for Bluetooth RFCOMM SDP L2CAP Host Controller Link Manager Protocol Link Controller Radio Hardware { Software Protocols + APIs { Firmware { Hardware

106 Bluetooth Pros & Cons Pros Local area networking Cons Slow handshaking Transfer media + files over standard protocol Complex implementation Communicates with numerous devices (GPS, phones, computers, PICs) Difficult to troubleshoot

107 Useful links Official Bluetooth Site (lots of technical info) Java Bluetooth JSR-82 Specification

108 Bluetooth Interactions 1. Discovery 2. Client activities / services 3. Server activities 4. Peer activities

109 Bluetooth Service Model s s Discovery (SDP) RFCOMM (Stream) L2CAP (Packet) s m s m s Client Service Master Slave

110 Devices + Services Services - identified by UUID UUID = Universally Unique Identifier 128 / 32 /16 bits Devices - identified by BluetoothAddress & FriendlyName ServiceRecord = entry in Service Discovery Database (SDDB) ServiceRecoed = ID + value

111 Your BT Stack Local BT Stack accessed with LocalDevice LocalDevice mydevice = LocalDevice.getLocalDevice() DiscoveryAgent.getFriendlyName() Methods int getdiscoverable() boolean setdiscoverable(int mode) static String getproperty(string property)

112 Properties bluetooth.api.version bluetooth.master.switch bluetooth.sd.attr.retrievable.max bluetooth.connected.devices.max bluetooth.l2cap.receivemtu.max bluetooth.sd.trans.max

113 Steps to connect 1. Access Local Device 2. Discover Devices (perform inquiry) 3. Discover Services (identified by UUID) 4. Connect with specific device / service

114 Concepts DiscoveryAgent DiscoveryAgent myda = LocalDevice.getInstance().getDiscoveryAgent(); Service level or device level discovery boolean startinquiry(int accesscode, DiscoveryListener listener) accesscode = General Inquiry Access Code (GIAC) or Limited Inquiry Access Code (LIAC) See