Java 2 Platform, Micro Edition           ( (J2ME               J2ME              1
Contents  What’sJ2ME?  J2ME core concepts     Configurations (CLDC, CDC(     Profiles (MIDP(  MIDlet,   MIDlet Suite ...
Introduction    Personalized and intelligent information appliances     are necessities in our life today.    Such appli...
Environment requirements  We   need an environment which is adapted for   constrained devices - devices that have   limit...
?So – what’s the solution  Because  of the vast   need, Sun has   decided to develop a   special edition of   Java - J2ME...
J2ME   6
Java Editions  Differentdevices have different   requirements and different expectations   of Java.  One platform (solut...
Java Editions  The  Java 2 Platform is split into three   editions.  Each edition provides a complete   environment for ...
Java Editions                            Java 2 Platform     Java2                       Java2               Java2 Standar...
Java Editions  Each   edition defines different sets of class   libraries.  There are thousands of core J2SE runtime   c...
PersonalJava and EmbeddedJava  J2ME  is not the first attempt at adapting   Java for constrained environments.  Personal...
PersonalJava and EmbeddedJava  EmbeddedJava    Makes  every behavior of the JVM and the     runtime classes optional - t...
J2ME Core Concepts  Configuration                                                          Profiles                      ...
J2ME Core Concepts J2ME is based on 3 core concepts:  Configurations  Profiles  Optional packages                    J2...
Configurations A  configuration is a complete Java   runtime environment, consisting of:    Java virtual machine (VM( to...
Configurations  The  set of core classes is normally quite   small and must be enhanced with   additional classes supplie...
Configurations                    Configuration                    Configuration          CLDC          CLDC              ...
CLDC vs. CDC    CLDC                             CDC       For very constrained             2 MB or more        device...
CLDC vs. CDC - VM  Features          missing in           The     CDC supports a  the CLDC VM:                     compl...
The KVM and CVM  KVM   - Java virtual machines for the CLDC  CVM - Java virtual machines for the CDC  Written specifica...
CLDC vs. CDC – J2SE Subset  TheCLDC includes      The  CDC includes  classes from:           17 packages    java.lang  ...
CLDC vs. CDC – J2SE Subset         J2SE    CDC   CLDC                J2ME          22
Handling I/O  J2SE   includes many classes for   performing input and output.  There are a large number of I/O classes  ...
Handling I/O in CLDC  The  CLDC has define a new set of APIs for I/O   called the Generic Connection Framework.  The GCF...
GCF - example  import java.io.*;  import javax.microedition.io.*;  StreamConnection conn = null;  InputStream is = null;  ...
Handling I/O in CDC  Since  the CDC is a superset of the   CLDC, it includes the GCF.  CDC also requires GCF support for...
J2ME Core Concepts J2ME is based on 3 core concepts:  Configurations  Profiles  Optional packages                    J2...
Profiles  Adds  domain-specific classes to a   configuration:     To fill in missing functionality     To support speci...
Profiles                            Profile                            Profile   MIDP   MIDP        PDAP               PDA...
MIDP – MID Profile  MIDP is targeted at a class of devices   known as mobile information devices   (MIDs).  Minimal char...
MIDP - Specification There   are two versions of the MIDP:   MIDP   1.0 - released in September    2000. Many devices cu...
MIDP - Specification  The  MIDP adds APIs to the basic APIs defined   by the CLDC. The new features include:    Support ...
MIDP - Specification  TheMIDP specification is silent about a   number of things:    No standard way to interface to the...
MIDP Applications restrictions  Memory     is a particularly scarce resource.       The early Motorola J2ME-enabled phon...
J2ME Core Concepts J2ME is based on 3 core concepts:  Configurations  Profiles  Optional packages                    J2...
Optional Packages  Set of APIs in support of additional,   common behaviors.  Have specific dependencies on a   particul...
What it all means  "J2ME   application" is an ambiguous term.  Configuration, profile and optional packages   should be ...
J2ME   38
…MIDlets – The heart of J2ME  MIDP   does not support the running of   applications that use a static main   method as th...
…MIDlets – The heart of J2ME  Every application must extend  javax.microedition.midlet.MIDlet class  to allow the applica...
…MIDlets – The heart of J2ME  The  extending class is the main class of   the application.  The MIDlet class defines abs...
MIDlet Suite  One  or more MIDlets are packaged   together into a MIDlet suite, composed   of:    JAR (Java archive) fil...
MIDlet Suite  The  JAR file must also include a   manifest that describe the MIDlets in the   suite.  The application de...
Creating a MIDlet                J2ME   44
Creating a MIDlet            Importing MIDP                                specific                               packages...
Creating a MIDlet                               Extends MIDlet                                Implements                  ...
Creating a MIDlet                                         Creating the                                         form, addin...
Sample MIDP classes API  MIDlet  Form  Command    CommandListener    ItemCommandListener  Item                      ...
Sample classes API MIDlet   – Base class  Form  Command    CommandListener    ItemCommandListener  Item             ...
MIDlet class API protected abstract void startApp() protected abstract void pauseApp() protected abstract void  destroy...
Sample classes API  MIDlet Form  Command    CommandListener    ItemCommandListener  Item                       J2ME ...
Form class A  Form is a Screen that contains an arbitrary   mixture of items: images, read-only text fields,   editable t...
Form class API Item   management   public int append(Item item)   public Item get(int itemNum) Layout  publicvoid  se...
Sample classes API  MIDlet  Form Command    CommandListener    ItemCommadListener  Item                       J2ME  ...
Command class  The Command class represents the semantic   meaning of an action. Command objects are   presented in the u...
Command class  Command label   public String getLabel()  Command type   public int getCommandType()  Command priority...
CommandListener class API  Thisobject is a listener for Commands  that are attached to a Displayable.  public void  comm...
ItemCommandListener class API  When   a command (attached to an Item)   is invoked, the application is notified by   havi...
Sample classes API  MIDlet  Form  Command    CommandListener    ItemCommandListener Item                       J2ME ...
Item class A  superclass for components that can be   added to a Form.  All Item objects have a label field  Choose the...
Item class API  public void   setDefaultCommand(Command cmd)  public void   setItemCommandListener(ItemCom   mandListene...
…Getting Started   1st      step: Download sun’s J2ME    Wireless Toolkit from:    http://java.sun.com/products/j2mewtool...
….After the installation  Shortcuts   are available from the start menu.  New  directories   created                    ...
Using KToolbar            J2ME   64
Creating a new Application  Press  “New Project”.  Enter the project’s name and the MIDlet’s   class name.  New directo...
Where to place your files? J2ME/apps/{proj}       source, resource, and binary                        files J2ME/apps/{pro...
And then what?  Choose      the target platform  Write your code Java Technology for the Wireless      JTWI - conforms t...
Distribution to actual devices  Create  a package  Place your code somewhere on the net.  Update .jad file  Download t...
Some other issues  OTA  provisioning  Using Servlets  Working with EclipseME  Web services                   J2ME     69
!The END   J2ME    70
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  • Stat with: Who doesn’t own a cellphone? Say that it is different than anything we knew until today.
  • The main difference is the size of libraries. 10-20 megabytes – too big for the majority of devices. Fewer classes – especially the smaller devices.
  • The Java runtime environment can only be used by the implementor and cannot be exposed to third parties
  • Class files are processed by an off-device class verifier, a process called preverification . At runtime, the VM uses information inserted into the class files by the preverifier to perform the final verification steps. Files that have not been processed by the preverifier are not loaded since they cannot be verified.
  • Many device manufacturers license the KVM or CVM from Sun Microsystems to serve as the core of their J2ME implementation, they are not required for J2ME compliance.
  • Only selected classes from each package are included: for example, the java.util.Vector and java.util.Hashtable classes are included, but none of the collection classes are. The largest package is the java.lang package, which defines the classes that are fundamental to any java application, classes like java.lang.Object or java.lang.Integer. The java.io subset only includes abstract and memory-based classes and interfaces like java.io.DataInput or java.io.ByteArrayInputStream. The java.util subset only includes a few utility classes.
  • It defines interfaces and a factory class for creating objects that implement those interfaces.
  • The code above assumes that the device knows how to map the "socket" protocol in the URL to an object that implements the GCF's StreamConnection interface, which defines methods for obtaining the input and output streams of a socket connection. It should be noted, however, that the CLDC does not actually define any I/O implementations. In other words, the CLDC defines the interfaces of the GCF, but the implementation classes -- the ones that do the actual I/O -- are left to the profiles and/or the device vendor to define. For example, the Mobile Information Device Profile (MIDP) -- a CLDC-based profile -- requires support for a subset of HTTP 1.1 and so it recognizes the "http" protocol in URLs and returns objects that implement the GCF's ContentConnection interface.
  • By itself, the CLDC is a limited programming platform. Because it does not define any user interface classes or implement any I/O models, about all you can do for output is write to the System.out stream, which may or may not be captured to a console or file. You really need the extra classes defined by a J2ME profile (like those of the MIDP) or device-specific classes (like those on the RIM BlackBerry devices or certain Japanese i-Mode phones) to do anything interactive.
  • Several profiles in various stages of development: Mobile Information Device Profile (MIDP) - CLDC-based, used for running applications on cellphones and interactive pagers with small screens, wireless HTTP connectivity, and limited memory. Personal Digital Assistant Profile (PDAP) – CLDC-based, extends MIDP with additional classes and features for more powerful handheld devices. Foundation Profile (FP) – CDC-based, extends the CDC with additional J2SE classes. Personal Basis Profile (PBP) - extends the FP with lightweight (AWT-derived) user interface classes and a new application model. Personal Profile extends the PBP with applet support and heavyweight UI classes.
  • Almost any wireless device built these days fits the definition of a MID, including low-end cellphones. Personal digital assistants (PDAs) can also be considered to be MIDs because wireless networking is now an option for most PDAs, but MIDP doesn't target these devices. Personal digital assistants (PDAs) can also be considered to be MIDs because wireless networking is now an option for most PDAs, but MIDP doesn't target these devices specifically: PDAs have more memory, larger screens, and interesting information management capabilities that are more effectively exploited using other profiles.
  • The MIDP 1.0 specification was defined by an expert group consisting of all the major players in the wireless and handheld device arena, including familiar names like Motorola, Nokia, Ericsson, Research in Motion, and Symbian. It has a lot of support in the telecommunications industry, and handset manufacturers like Motorola and Nokia in particular are devoting a lot of development effort to supporting MIDP in a wide range of their devices.
  • J2ME enabled phones raised to 100K on more recent models
  • Have minimum requirements. RMI – Remote Method Invocation JDBC – Java Data Base Connectivity
  • The first concept we have to understand is the MIDlet
  • Extends MIDlet like extending Applet class
  • A Java Application Descriptor (JAD) file. This file contains a predefined set of attributes that allows the device application management software to identify, retrieve, and install the MIDlets. A Java Archive (JAR) file. The JAR file contains Java classes for each MIDlet in the suite and Java classes that are shared between MIDlets. The JAR file also contains resource files used by the MIDlets and a manifest file.
  • Show manifest and jad files
  • Show the DEMO – HelloSuite.
  • The items contained within a Form may be edited using append, delete, insert, and set methods. Items within a Form are referred to by their indexes An item may be placed within at most one Form Items Layout - Layout policy in Form is organized around rows . Forms grow vertically and scroll vertically as necessary. The height of a Form varies depending upon the number of rows and the height of each row. An implementation may choose to lay out Items in a left-to-right or right-to-left direction depending upon the language conventions in use. You can use LAYOUT_LEFT, LAYOUT_RIGHT,LAYOUT_CENTER, considering row-breaks etc.
  • Displayable: (an object that has the capability of being placed on the display(Screen,Canvas)
  • Possible Command types: The defined types are BACK , CANCEL , EXIT , HELP , ITEM , OK , SCREEN , and STOP .
  • CommandListener – attaching the listener to the entire screen, the command can be of type SCREEN or anything else…
  • ItemCommandListener attaching the listener to a specific item, the command should be of type ITEM. A listener type for receiving notification of commands that have been invoked on Item objects.
  • Item has many layouts, including LAYOUT_DEFAULT , LAYOUT_LEFT , LAYOUT_RIGHT , LAYOUT_CENTER , LAYOUT_TOP , LAYOUT_BOTTOM , LAYOUT_VCENTER , LAYOUT_NEWLINE_BEFORE , LAYOUT_NEWLINE_AFTER , LAYOUT_SHRINK, LAYOUT_VSHRINK , LAYOUT_EXPAND , LAYOUT_VEXPAND , LAYOUT_2 Sizes: the implementor can set the sizes of an item. If the application attempts to lock a preferred size dimension to a value smaller than the minimum or larger than the maximum, the implementation may disregard the requested value and instead use either the minimum or maximum as appropriate. If this occurs, the actual values used must be visible to the application via the values returned from the getPreferredWidth and getPreferredHeight methods. Appearance: The StringItem and ImageItem classes have an appearance mode attribute that can be set in their constructors. This attribute can have one of the values PLAIN, HYPERLINK, or BUTTON
  • There’s sun’s download center Choose the relevant operating system. Available for windows, linux, solaris. (not for OS X, although MIDP is available). You need java sdk 1.3 or higher Install the toolkit in a directory with no space in its name…
  • KToolbar is the main working tool to handle J2ME applications You can create a new project, open an existing one, choose the emulator device, change the settings, build (compile and preverify) and run the simulation.
  • When creating a new project, you have to give it a name ( the name of the project will be the name of the directory under apps), and give the name of the MIDlet class.
  • Target setting - The project settings information and tabs change based on the selection you choose for the target platform. Some project settings are not applicable for a selected target platform. Building using the KToolbar – creating the classes and the .jad file Preverify – makes sure that the .jad is updated with the .jar files. That the used classes in the application are available in the chosen target platform. Doing so allows the device using the application without further checking which require more memory and cpu. Run – with the emulator, from the KToolbar
  • Finally, MIDlets are bundled into MIDlet suites for distribution to actual devices. This process entails JARing the MIDlet suite class files and the resource files, and putting some extra information in the JAR manifest. Again, these chores are best left to the J2ME Wireless Toolkit. To bundle up your MIDlet suite, select Project | Package from the menu. The .jad and .jar files for the MIDlet suite will be generated and placed in the bin directory of the project. The .jad file should contain the correct address of where the files are located on the net.
  • Once your application is in a stable state, you are ready to see how your application performs in a more realistic environment, that is the downloading and running of your application onto a mobile device from a browser or server. At this point, you will want to run your application using Over-The-Air (OTA) provisioning. The J2ME Wireless Toolkit simulates OTA provisioning, that allows you to test the functionality of your application and demonstrate the full provisioning process of your MIDlet suite from a web server to a device. With simulated OTA provisioning in the Wireless Toolkit, the MIDlet suite is packaged in the JAR and JAD format, deployed to the provisioning server, and downloaded to an emulated device.
  • J2me

    1. 1. Java 2 Platform, Micro Edition ( (J2ME J2ME 1
    2. 2. Contents  What’sJ2ME?  J2ME core concepts  Configurations (CLDC, CDC(  Profiles (MIDP(  MIDlet, MIDlet Suite  Basic classes API  Installation and using the Toolkit  Demos!!! J2ME 2
    3. 3. Introduction  Personalized and intelligent information appliances are necessities in our life today.  Such appliances can be:  cellphones  two-way pagers  smart cards  personal organizers  palmtops  These appliances tend to be special-purpose, limited-resource, network-connected devices. J2ME 3
    4. 4. Environment requirements  We need an environment which is adapted for constrained devices - devices that have limitations on what they can do when compared to standard desktop or server computers.  The constraints are:  extremely limited memory  small screen sizes  alternative input methods  slow processors J2ME 4
    5. 5. ?So – what’s the solution  Because of the vast need, Sun has decided to develop a special edition of Java - J2ME (Java 2 Micro Edition). J2ME 5
    6. 6. J2ME 6
    7. 7. Java Editions  Differentdevices have different requirements and different expectations of Java.  One platform (solution( cannot address all the market segments (web server, video games etc.(  Users/developers want flexibility. They want to choose what they want to use and what they do not. J2ME 7
    8. 8. Java Editions  The Java 2 Platform is split into three editions.  Each edition provides a complete environment for running Java-based applications, including the Java virtual machine (VM( and runtime classes.  The three editions target different kinds of applications running on different kinds of devices. J2ME 8
    9. 9. Java Editions Java 2 Platform Java2 Java2 Java2 Standard Edition Enterprise Edition Micro Edition (J2SE™) (J2EE™) (J2ME™) Standard desktop & Heavy duty server Small & memory workstation applications systems constrained devices J2ME 9
    10. 10. Java Editions  Each edition defines different sets of class libraries.  There are thousands of core J2SE runtime classes, taking up to 10-20 megabytes of space.  J2ME-based devices have J2EE fewer classes. J2SE J2ME J2ME 10
    11. 11. PersonalJava and EmbeddedJava  J2ME is not the first attempt at adapting Java for constrained environments.  PersonalJava  Uses the basic Java 1.1 runtime classes with a few features from Java 2.  Implementation still requires a couple of megabytes of memory and a fast processor to run. J2ME 11
    12. 12. PersonalJava and EmbeddedJava  EmbeddedJava  Makes every behavior of the JVM and the runtime classes optional - the implementor can choose exactly which classes and methods are required.  The limitation: "write once, run anywhere". J2ME 12
    13. 13. J2ME Core Concepts  Configuration Profiles J2ME  Minimum platform Profile required for a group of devices J2ME  Profile Libraries Configuration  Addresses specific Java Language needs of a certain device family Java Virtual Machine  Optional Packages Host Operating System J2ME 13
    14. 14. J2ME Core Concepts J2ME is based on 3 core concepts:  Configurations  Profiles  Optional packages J2ME 14
    15. 15. Configurations A configuration is a complete Java runtime environment, consisting of:  Java virtual machine (VM( to execute Java bytecode  Native code to interface to the underlying system  Set of core Java runtime classes  Touse a configuration, a device must meet certain minimum requirements. J2ME 15
    16. 16. Configurations  The set of core classes is normally quite small and must be enhanced with additional classes supplied by J2ME profiles or by configuration implementor.  Configurations do not define any user interface classes. J2ME 16
    17. 17. Configurations Configuration Configuration CLDC CLDC CDC CDC Connected Limited Connected Device Device Configuration Configuration J2ME 17
    18. 18. CLDC vs. CDC  CLDC  CDC  For very constrained  2 MB or more devices memory for Java  160 - 512 KB of total platform memory  32-bit processor  16-bit or 32-bit  High bandwidth processor network connection,  Low power most often using consumption and TCP/IP often operating with battery power  Connectivity with limited bandwidth J2ME 18
    19. 19. CLDC vs. CDC - VM  Features missing in  The CDC supports a the CLDC VM: complete, full- featured Java 2  Floating point types virtual machine  Object finalization  JNI or reflection  Thread groups or daemon threads  User Class loaders  Change in classfile verification  preverification J2ME 19
    20. 20. The KVM and CVM  KVM - Java virtual machines for the CLDC  CVM - Java virtual machines for the CDC  Written specifically to work in the constrained environment of a handheld or embedded device and to be easily ported to different platforms.  CLDC and CDC specifications do not require the use of the KVM or the CVM. J2ME 20
    21. 21. CLDC vs. CDC – J2SE Subset  TheCLDC includes  The CDC includes classes from: 17 packages  java.lang  Includes more  java.io classes even in the  java.util shared packages  Onlyselected classes from each package are included J2ME 21
    22. 22. CLDC vs. CDC – J2SE Subset J2SE CDC CLDC J2ME 22
    23. 23. Handling I/O  J2SE includes many classes for performing input and output.  There are a large number of I/O classes and they tend to encapsulate I/O models that are not necessarily found on all devices.  For example, some handheld devices do not have file systems. Socket support is not universal, either. J2ME 23
    24. 24. Handling I/O in CLDC  The CLDC has define a new set of APIs for I/O called the Generic Connection Framework.  The GCF, part of the new javax.microedition.io package, defines interfaces for the different kinds of I/O that are possible.  The CLDC does not actually define any I/O implementations these are left to the profiles and/or the device vendor to define. J2ME 24
    25. 25. GCF - example import java.io.*; import javax.microedition.io.*; StreamConnection conn = null; InputStream is = null; String url = "socket://somewhere.com:8909"; try { conn = (StreamConnection) Connector.open( url ); is = conn.openInputStream(); .... // etc. etc. }… J2ME 25
    26. 26. Handling I/O in CDC  Since the CDC is a superset of the CLDC, it includes the GCF.  CDC also requires GCF support for two specific connection types: files and datagrams.  The reason: CDC includes the relevant classes from java.io and java.net packages. J2ME 26
    27. 27. J2ME Core Concepts J2ME is based on 3 core concepts:  Configurations  Profiles  Optional packages J2ME 27
    28. 28. Profiles  Adds domain-specific classes to a configuration:  To fill in missing functionality  To support specific uses of a device  Most profiles define user interface classes for building interactive applications.  To use a profile, the device must meet the minimum requirements of the underlying configuration and of the profile. J2ME 28
    29. 29. Profiles Profile Profile MIDP MIDP PDAP PDAP FP FP PBP PBP PP PP Mobile Personal Foundation Personal PersonalInformation Digital Profile Basis Profile Profile Device Assistant Profile Profile J2ME 29
    30. 30. MIDP – MID Profile  MIDP is targeted at a class of devices known as mobile information devices (MIDs).  Minimal characteristics of MIDs:  Enough memory to run MIDP applications  Display of at least 96 X 56 pixels, either monochrome or color  A keypad, keyboard, or touch screen  Two-way wireless networking capability J2ME 30
    31. 31. MIDP - Specification There are two versions of the MIDP: MIDP 1.0 - released in September 2000. Many devices currently on the market support it. MIDP 2.0 - currently in proposed final draft form. No devices yet support it. J2ME 31
    32. 32. MIDP - Specification  The MIDP adds APIs to the basic APIs defined by the CLDC. The new features include:  Support for application lifecycle management similar to the way applets are defined in J2SE.  Persistent storage of data.  HTTP-based network connectivity based on the CLDCs GCF.  Simple user interface support, with enough flexibility to build games or business applications. J2ME 32
    33. 33. MIDP - Specification  TheMIDP specification is silent about a number of things:  No standard way to interface to the devices phonebook, in order to initiate voice calls.  How MIDP applications are loaded onto a device and how they are activated or deactivated. J2ME 33
    34. 34. MIDP Applications restrictions  Memory is a particularly scarce resource.  The early Motorola J2ME-enabled phones limited the size of an application to 50K. Some Nokia phones limit them to even less, about 30K.  MIDP 1.0 applications cannot share classes.  Placing part of the application in a web or application server (as a servlet, typically) that the MIDP application calls is almost a requirement for anything serious. J2ME 34
    35. 35. J2ME Core Concepts J2ME is based on 3 core concepts:  Configurations  Profiles  Optional packages J2ME 35
    36. 36. Optional Packages  Set of APIs in support of additional, common behaviors.  Have specific dependencies on a particular configuration and/or one or more profiles.  Examples of optional packages :  RMI Optional Package  Bluetooth Optional Package  JDBC Optional Package J2ME 36
    37. 37. What it all means  "J2ME application" is an ambiguous term.  Configuration, profile and optional packages should be chosen.  CDC-based profiles make development simpler due to J2SE-like APIs, but don’t suit the low-end devices.  CLDC-based profiles makes the development task harder, especially when trying to shrink the size of the application to run on many of the small devices. J2ME 37
    38. 38. J2ME 38
    39. 39. …MIDlets – The heart of J2ME  MIDP does not support the running of applications that use a static main method as their entry point, nor calling the System.exit method in order to terminate.  Instead, we use a MIDlet, which is a MID Profile application. J2ME 39
    40. 40. …MIDlets – The heart of J2ME  Every application must extend javax.microedition.midlet.MIDlet class to allow the application management software to:  control the MIDlet  be able to retrieve properties from the application descriptor  notify and request state changes J2ME 40
    41. 41. …MIDlets – The heart of J2ME  The extending class is the main class of the application.  The MIDlet class defines abstract methods that the main class implements (for example: startApp(), destroyApp(), notifyDestroyed()). J2ME 41
    42. 42. MIDlet Suite  One or more MIDlets are packaged together into a MIDlet suite, composed of:  JAR (Java archive) file  JAD (Java Application Descriptor) file  Allthe user-defined classes and resources required by the suites MIDlets must be in the JAR file. J2ME 42
    43. 43. MIDlet Suite  The JAR file must also include a manifest that describe the MIDlets in the suite.  The application descriptor (JAD) contains similar information, and is used by devices to obtain information about a MIDlet suite without having to download and install the MIDlet suite first. J2ME 43
    44. 44. Creating a MIDlet J2ME 44
    45. 45. Creating a MIDlet Importing MIDP specific packages import javax.microedition.lcdui.*; import javax.microedition.midlet.*; J2ME 45
    46. 46. Creating a MIDlet Extends MIDlet Implements CommandListener public class HelloMIDlet extends MIDlet implements CommandListener { J2ME 46
    47. 47. Creating a MIDlet Creating the form, adding the Commands public HelloMIDlet() { mMainForm = new Form("HelloMIDlet"); mMainForm.append(new StringItem(null, "Hello, Seminar Software Design!")); mMainForm.addCommand(new Command("Exit", Command.EXIT, 0)); mMainForm.setCommandListener(this); } J2ME 47
    48. 48. Sample MIDP classes API  MIDlet  Form  Command  CommandListener  ItemCommandListener  Item J2ME 48
    49. 49. Sample classes API MIDlet – Base class  Form  Command  CommandListener  ItemCommandListener  Item J2ME 49
    50. 50. MIDlet class API protected abstract void startApp() protected abstract void pauseApp() protected abstract void destroyApp(boolean unconditional) public final String getAppProperty(String key) public final void notifyDestroyed() J2ME 50
    51. 51. Sample classes API  MIDlet Form  Command  CommandListener  ItemCommandListener  Item J2ME 51
    52. 52. Form class A Form is a Screen that contains an arbitrary mixture of items: images, read-only text fields, editable text fields, editable date fields, gauges, choice groups, and custom items.  In general, any subclass of the Item class may be contained within a form.  The implementation handles layout, traversal, and scrolling. J2ME 52
    53. 53. Form class API Item management public int append(Item item) public Item get(int itemNum) Layout  publicvoid setItemStateListener(ItemState Listener iListener) J2ME 53
    54. 54. Sample classes API  MIDlet  Form Command  CommandListener  ItemCommadListener  Item J2ME 54
    55. 55. Command class  The Command class represents the semantic meaning of an action. Command objects are presented in the user interface.  The action itself is implemented in a CommandListener object.  The CommandListener is associated with a Displayable or an Item.  Once the Command is called – the CommandListener is invoked, and the action is performed. J2ME 55
    56. 56. Command class  Command label public String getLabel()  Command type public int getCommandType()  Command priority public int getPriority() J2ME 56
    57. 57. CommandListener class API  Thisobject is a listener for Commands that are attached to a Displayable.  public void commandAction(Command c, Displayable d) J2ME 57
    58. 58. ItemCommandListener class API  When a command (attached to an Item) is invoked, the application is notified by having the commandAction() method called on the ItemCommandListener that had been set on the Item.  public void commandAction(Command c, Item item) J2ME 58
    59. 59. Sample classes API  MIDlet  Form  Command  CommandListener  ItemCommandListener Item J2ME 59
    60. 60. Item class A superclass for components that can be added to a Form.  All Item objects have a label field  Choose the Item’s layout, size, and appearance  Attach Commands J2ME 60
    61. 61. Item class API  public void setDefaultCommand(Command cmd)  public void setItemCommandListener(ItemCom mandListener listener)  public void notifyStateChanged()  public int getPreferredWidth() J2ME 61
    62. 62. …Getting Started 1st step: Download sun’s J2ME Wireless Toolkit from: http://java.sun.com/products/j2mewtoolkit/d ownload-2_1.html 2nd step: Make sure you have J2SE SDK installed 3rd step: Install the J2ME Toolkit. J2ME 62
    63. 63. ….After the installation  Shortcuts are available from the start menu.  New directories created J2ME 63
    64. 64. Using KToolbar J2ME 64
    65. 65. Creating a new Application  Press “New Project”.  Enter the project’s name and the MIDlet’s class name.  New directories will automatically be created. J2ME 65
    66. 66. Where to place your files? J2ME/apps/{proj} source, resource, and binary files J2ME/apps/{proj}/bin JAR, JAD, unpacked manifest files. J2ME/apps/{proj}/lib external class libraries, (JAR or ZIP) for a specific project J2ME/apps/{proj}/res resource files J2ME/apps/{proj}/src source files external class libraries, (JAR or J2ME/apps/lib ZIP) for all KToolbar projects. J2ME 66
    67. 67. And then what?  Choose the target platform  Write your code Java Technology for the Wireless JTWI - conforms to Industry (JSR-185).  Save MIDP1.0 - includes MIDP 1.0 and CLDC 1.0 Custom - user defined settings, you can select project  Build profile, configurations and various APIs. (Compile + Preverify)  Run J2ME 67
    68. 68. Distribution to actual devices  Create a package  Place your code somewhere on the net.  Update .jad file  Download the application to your mobile  Start playing…  J2ME 68
    69. 69. Some other issues  OTA provisioning  Using Servlets  Working with EclipseME  Web services J2ME 69
    70. 70. !The END J2ME 70

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