·                     HTTP Networking

javax.microedition.io.HttpConnection is used for working with HTTP connections. MIDP 2.0 enabled device must support the HTTP 1.1 servers and services.

·                     Secure Connections

javax.microedition.io.HttpsConnection is used for working with secure connections.

·                     Low Level Networking Support

The MIDP 2.0 specification also supports the TCP/IP sockets and the UDP/IP datagrams.

·                     Push Applications Support

MIDP 2.0 includes the support for PushRegistry. The PushRegistry maintains a list of inbound connections. Whenever the application management software receives a notification for a MIDlet that has registered itself for inbound notifications the particular MIDlet is started by the application management software. This feature can be used for chat, news and ERP applications.

·                     Serial Port Connections

We can access the local serial port in form of a stream connection with the help of the interface javax.microedition.io.CommConnection.

The networking support in this package is based on the Generic Connection Framework provided to us in the Connected, Limited Device Configuration. 

public interface CommConnection

What is it?

o    A logical serial port connection is defined by the interface javax.microedition.io.CommConnection. A logical serial port may be a RS – 232 port or an IrDA IRCOMM port. One serial port can be used by only one application at a particular time.

o    Methods

·         public int getBaudRate()

This method returns the baud rate of the connection.

·         public int setBaudRate(int baudrate)

This method is used for setting the baud rate for a serial port connection. This method returns the previous baud rate of the connection.

public class Connector

What is it?

Connector is a factory class for creating new Connection objects. This class dynamically returns the appropriate type on Connection based upon the value of the arguments in its open method.

o    Fields

·         public static final int READ

The field for the access mode READ.

Value: 1

·         public static final int READ_WRITE

READ_WRITE is the field for the access mode READ_WRITE.

Value: 3

·         public static final int WRITE

WRITE is the field for the access mode WRITE.

Value: 2 

o    Methods

·         public static javax.microedition.io.Connection open(String name)

This method returns a new Connection object.

·         public static javax.microedition.io.Connection open(String name, int mode)

This method returns a new Connection object.

·         public static javax.microedition.io.Connection open(String name, int mode, boolean timeouts)

This method returns a new Connection object

·         public static java.io.DataInputStream openDataInputStream(String name)

This method returns a DataInputStream.

·         public static java.io.DataOutputStream openDataOutputStream(String name)

This method returns a DataOutputStream.

·         public static java.io.InputStream openInputStream(String name)

This method returns an InputStream.

·         public static java.io.OutputStream openOutputStream(String name)

This method returns an OutputStream.

public interface HttpsConnection

What is it?

HttpsConnection defines the necessary methods and constants to establish a secure network connection.

o    Methods

·         public int getPort()

This method returns the network port number of the URL for this HttpsConnection. If no port number is passed in the string is passed to Connector.open then the default HTTPS port number (443) is returned.

·         public SecurityInfo getSecurityInfo()

This method returns the security information associated with this open connection.

public interface SecureConnection

What is it?

o    SecureConnection interface defines the secure socket stream connection. A CertificateException is thrown if the secure connection cannot be established due to errors related to certificates.

o    Methods

·         public SecurityInfo getSecurityInfo()

This method returns the security information associated with this open connection.

public interface SecurityInfo

What is it?

o    SecurityInfo interface provides us with the methods to access information about a secure network connection. This interface provides the following:

·   Protocol

·   Version

·   Certificate

·   Cipher suite

o    Methods

·         public java.lang.String getCipherSuite()

This method returns a String containing the name of the cipher suite in use.

·         public java.lang.String getProtocolName()

This method returns the name of the secure protocol.

The following are the return values for the respective connections:

·   TLS (RFC 2246) /WAP TLS Profile and Tunneling (WAP-219-TLS)

Return value: “TLS” 

·   SSL V3 (The SSL Protocol Version 3.0)

Return value: “SSL” 

·   WTLS (WAP 199)

Return value: “WTLS”.

·         public java.lang.String getProtocolVersion()

This method returns a String containing the version of the protocol.

·         public javax.microedition.pki.Certificate getServerCertificate()

This method returns the Certificate used to establish the secure connection with the server.

public interface ServerSocketConnection

What is it?

o    ServerSocketConnection interface defines the server socket stream connection.

o    Methods

·         public java.lang.String getLocalAddress()

This method returns the local address to which this socket is bound.

·         public int getLocalPort()

This method returns the local port number to which the socket is connected.

public interface SocketConnection

What is it?

o    SocketConnection defines the socket stream connection.

o    Fields

• public static final byte DELAY

·         public static final byte KEEPALIVE

·         public static final byte LINGER

·         public static final byte RCVBUF

·         public static final byte SNDBUF

o    Methods

• public java.lang.String getAddress()

This method returns the remote address to which the socket is bound.

·         public java.lang.String getLocalAddress()

This method returns the local address to which the socket is bound.

·         public int getLocalPort()

This method returns the local port number to which this socket is connected.

·         public int getPort()

This method returns the remote port number to which this socket is connected.

·         public int getSocketOption(byte option)

This method returns numeric value for specified option or -1 if the value is not available.

·         public void setSocketOption(byte option, int value)

This method is used for setting a socket option for the connection.

public interface UDPDatagramConnection

What is it?

o    UDPDatagramConnection interface defines a datagram connection. This protocol is transaction oriented and the delivery can not be guaranteed.

o    Methods

• public String getLocalAddress()throws Exception

This method returns the local address to which the datagram connection is bound.

·         public int getLocalPort()throws Exception

This method returns the local port number to which this datagram connection is connected.

public class PushRegistry

What is it?

This class maintains a list of inbound connections. An application can register for the inbound connections by the following ways:

·   Entry in the application descriptor file

·   By calling the registerConnection method

When an application is not running, the application management software (AMS) keeps the track for inbound notification requests. When a notification arrives for a MIDlet that has registered itself, AMS will start that MIDlet normally through the startApp method. When the application is running, the application is responsible for all input and output operations associated with the inbound connection.

o    Methods

• public static java.lang.String  getFilter(String connection)

This method returns a filter string indicating which senders are allowed to cause the MIDlet to be launched. If the connection was not registered by the current MIDlet suite or if the connection argument was containing null this method will return null.

• public static java.lang.String getMIDlet(String connection)

This method returns class name of the MIDlet to be launched when the new external data is available. If the connection was not registered by the current MIDlet suite or if the connection argument was containing null this method will return null.

• public static java.lang.String[] listConnections(boolean available)

This method returns array of registered connection strings.

• public static long registerAlarm(String midlet, long time)

This method returns the time at which the most recent execution of this MIDlet was scheduled to occur. The format is the same as returned by Date.getTime()

• public static void registerConnection(String connection, String midlet, Stringfilter)

This method register’s a dynamic connection with the application management software (AMS). Once a connection is registered, the dynamic connection acts just like a connection pre-allocated from the descriptor file.

• public static boolean unregisterConnection(String connection)

This method returns true if the un-registration process was successful or it returns false if the connection was not registered or if the connection argument was null.

javax.microedition.lcdui

In MIDP 2.0 many new changes have been introduced in javax.microedition.lcdui package. Some classes have been introduced for the first time. All the methods and fields have been given for such classes. Some of the existing classes and interfaces have also been changed. For these classes and interfaces, I have at some places given only the additions made by MIDP 2.0 and at some other places given all the methods or fields as the need arose. For example in case of Alert only the new additions are given while in case of Canvas all the methods are given for a better understanding. I would also recommend you to read the appendix D of this book which contains the short description and a list of all the fields and methods of each and every interface and class in MIDP 1.0.

public class Alert

What is it

The alert class is a kind of screen that shows some data to the user. It waits for a certain period of time before proceeding to the next Displayable. It is basically a sort of simple dialog box that only gives some information. 

            

o    Fields

• public static final Command DISMISS_COMMAND

DISMISS_COMMAND is a Command that is delivered to a command listener to indicate that the Alert has been dismissed. 

o    Methods

·         public javax.microedition.lcdui.Gauge getIndicator()

This method returns a reference to this Alert's activity indicator. It returns null if there is no indicator in the alert.

·         public void removeCommand (javax.microedition.lcdui.Command cmd)

The important thing to keep in mind while using this method is that calling this method with DISMISS_COMMAND as the parameter has no effect.

·         public void setIndicator (javax.microedition.lcdui.Gauge indicator)

This method sets an activity indicator on this Alert. 

public abstract class Canvas

What is it?

This class is the base class for applications that need to handle low-level events and to issue graphics calls for drawing to the display. This class is very useful for graphics programming.

o    Methods

·         public int getGameAction(int keyCode)

This method returns the game action for this key. It will return 0 if no game action is there for the key.

• public int getHeight()

This method returns height of the displayable area. The value returned by this method can change during the execution of the application due variety of factors. The sizeChanged method has been added in MIDP 2.0 to notify us when the size of the displayable area is changed.

• public int getKeyCode(int gameAction)

This method returns a key code corresponding to the game action given in the argument.

• public java.lang.String getKeyName(int keyCode)

This method returns a string name for the key specified in the keyCode argument.

• public int getWidth()

This method returns width of the displayable area. The value returned by this method can change during the execution of the application due variety of factors. The sizeChanged method has been added in MIDP 2.0 to notify us when the size of the displayable area is changed.

• public boolean hasPointerEvents()

This method returns true if device supports pointer events.

• public boolean hasPointerMotionEvents()

This method returns true if device supports pointer motion events.

• public boolean hasRepeatEvents()

This method returns true if device supports repeat events

• public protected void hideNotify()

This method is called shortly after the Canvas has been removed from the display.

• public boolean isDoubleBuffered()

This method returns true if double buffering is there else this method will return false.

• protected void keyPressed(int keyCode)

This method is called when a key is pressed.

• protected void keyReleased(int keyCode)

This method is called when a key is released.

• protected void keyRepeated(int keyCode)

This method is called when a key is repeated (held down).

• protected abstract void paint(Graphics g)

This method is called for rendering the Canvas.

• protected void pointerDragged(int x, int y)

This method is called when the pointer is dragged.

• protected void pointerPressed(int x, int y)

This method is called when the pointer is pressed.

• protected void pointerReleased(int x, int y)

This method is called when the pointer is released.

• public void repaint()

This method requests a repaint for the entire Canvas.

• public void repaint(int x, int y, int width, int height)

This method is requests a repaint for the specified region of the Canvas.

• public void serviceRepaints()

This method forces any pending repaint requests to be serviced immediately.

·         public void setFullScreenMode(boolean mode)

This method provides us with a much desired control over the full screen mode of the Canvas. For setting the full screen mode the argument should be true otherwise it should be false.

• protected void showNotify()

The showNotify () method is called immediately prior to this Canvas being made visible on the display.

• protected void sizeChanged(int w, int h)

This method is called when the area of the Canvas which can be used for drawing upon has been changed. This method can be called due to a variety of factors.

public interface Choice

What is it?

This interface defines the characteristics of a user interface component implementing selection from predefined number of choices.

o    Fields

• public static final int EXCLUSIVE

This field stands for EXCLUSIVE choice. This kind of user interface element has exactly one element selected at one time.

• public static final int IMPLICIT

This field stands for IMPLICIT choice. In this kind of user interface element the currently focused element is selected when a Command is initiated.

• public static final int MULTIPLE

This field stands for MULTIPLE choices. This kind of user interface element can have an arbitrary number of elements selected at a given time.

• public static final int POPUP

This is a new field that has been added in MIDP 2.0. This is kind of a choice having exactly one element selected at one time and only this selected option is displayed until the user performs the particular action that will make all the elements visible. This choice type is not valid type for List class.

• public static final int TEXT_WRAP_DEFAULT

This is a new field that has been added in MIDP 2.0. This field indicates that the application has no preference as to wrapping or truncation of text element contents and that the implementation should use its default behavior.

• public static final int TEXT_WRAP_OFF

This is a new field that has been added in MIDP 2.0. This field indicates that text element contents should be limited to a single line.

• public static final int TEXT_WRAP_ON

This is a new field that has been added in MIDP 2.0. This field indicates that text element contents should be wrapped to multiple lines if necessary to fit available content space.

o    Methods

• public void deleteAll()

This method deletes all the elements from this Choice.

• public int getFitPolicy()

This method gets the application’s preferred policy for fitting Choice element contents to the available screen space. This method will return one of the 3 options given below: 

·   public static final int TEXT_WRAP_DEFAULT

·   public static final int TEXT_WRAP_OFF

·   public static final int TEXT_WRAP_ON

• public Font getFont(int elementNum)

This method returns the preferred font to use to render the specified element.

• public void setFitPolicy(int fitPolicy)

This method sets the application’s preferred policy for fitting Choice element contents to the available screen space. This method can contain one of the 3 options given below in its argument:

·   public static final int TEXT_WRAP_DEFAULT

·   public static final int TEXT_WRAP_OFF

·   public static final int TEXT_WRAP_ON

• public void setFont(int elementNum, Font font)

This method sets the preferred font for rendering the specified element of this Choice.

public class ChoiceGroup

What is it?

The changes in ChoiceGroup are mainly due to the changes in Interface Choice which is implemented in ChoiceGroup and class Item, which is the super class of ChoiceGroup. The changes in Choice and Item are given in detail in there respective texts.

public class Command

What is it?

This class encapsulates the semantic information of an action. The implementation of Command is device dependent. On some devices the commands are displayed on soft keys while on others they are shown in form of menus and lists. Thus care should be taken of testing the reaction of devices on adding commands. Generally the devices add the first 2 commands above the soft keys.

o    Constructors

• public Command(String shortLabel, String longLabel, int commandType,int priority)

This constructor constructs a new command object with the given long and short labels, type and priority.

o    Methods

• public java.lang.String getLongLabel()

This method returns the Command's long label. If the command has no long label a null is returned.

public abstract class CustomItem

What is it?

One of the problems in MIDP 1.0 was that we could not create customized items. To eliminate this problem the CustomItem has been introduced. This class is customizable by sub classing to introduce new kinds of visual and interactive elements into Forms. This class is very similar to the Canvas class but it has been written keeping in mind that sub classes of this class will be appended to forms.

o    Constructors

·         public protected CustomItem(String label)

This constructor has been provided so that the CustomItem subclass can specify its label.

o    Fields

• protected public static final  int KEY_PRESS

Value: 4.

• protected public static final  int KEY_RELEASE

Value: 8.

• protected public static final  int KEY_REPEAT

Value: 0x10.

• protected public static final  int NONE

Value: 0.

• protected public static final  int POINTER_DRAG

Value: 0x80.

• protected public static final  int POINTER_PRESS

Value: 0x20.

• protected public static final  int POINTER_RELEASE

Value: 0x40.

• protected public static final  int TRAVERSE_HORIZONTAL

Value: 1.

• protected public static final  int TRAVERSE_VERTICAL

Value: 2.

o    Methods

·         public int getGameAction(int keyCode)

This method returns the game action corresponding to the key specified in this argument. It returns 0 if no game action is there for this key.

• protected int getInteractionModes()

This method returns a bit mask of the available interaction modes

• protected abstract int getMinContentHeight()

This method returns the minimum content height in pixels.

• protected abstract int getMinContentWidth()

This method returns the minimum content width in pixels.

• protected abstract int getPrefContentHeight(int width)

This method returns the preferred content height in pixels.

• protected abstract int getPrefContentWidth(int height)

This method returns the preferred content width in pixels.

• protected void hideNotify()

This method is called by the system to notify that the item is now completely invisible. No further calls to the paint() method will be made on this item until after a showNotify() has been called again.

• protected void invalidate()

This method signals that the CustomItem's size and traversal location need to be updated.

• protected void keyPressed(int keyCode)

This method is called by the system when a key is pressed.

• protected void keyReleased(int keyCode)

This method is called by the system when a key is released.

• protected void keyRepeated(int keyCode)

This method is called by the system when a key is repeated.

• protected abstract void paint(Graphics g, int w, int h)

This method will be called to render the sub class of CustomItem. This method will be called only if the height and width of the CustomItem is greater than 0.

• protected void pointerDragged(int x, int y)

This method is called by the system when a pointer drag action has occurred within the item. The x and y coordinates of this method are relative to the origin of the item.

• protected void pointerPressed(int x, int y)

This method is called by the system when a pointer down action has occurred within the item. The x and y coordinates of this method are relative to the origin of the item.

• protected void pointerReleased(int x, int y)

This method is called by the system when a pointer up action has occurred after a pointer down action had occurred within the item. The x and y coordinates of this method are relative to the origin of the item.

• protected void repaint()

This method is called by subclass code to request that the item needs to be repainted.

• protected void repaint(int x, int y, int w, int h)

This method is called by subclass code to request that the specified rectangular area of the item needs to be repainted.

• protected void showNotify()

This method is called by the system to notify the item that it is now at least partially visible.

• protected void sizeChanged(int w, int h)

This method is implemented by the subclass in order to handle size change events.

• protected boolean traverse(int dir, int viewportWidth, int viewportHeight,int[] visRect_inout)

This method is called by the system when traversal has entered the item or has occurred within the item.

• protected void traverseOut()

This method is called by the system when traversal has occurred out of the item.

public class Display

What is it?

The class Display represents the manager of the display and input devices of the system and it also includes methods for retrieving properties of the device and for requesting that objects be displayed on the device.

o    Fields

• public static final  int ALERT

This field represents the Image type for Alert image.

• public static final  int CHOICE_GROUP_ELEMENT

This field represents the Image type for ChoiceGroup element image.

• public static final  int COLOR_BACKGROUND

This field specifies the color type for use with getColor method. This field specifies the background color of the screen.

• public static final  int COLOR_BORDER

This field specifies the color type for use with getColor method. This field specifies the color for boxes and borders when the object is to be drawn in a non-highlighted state.

• public static final  int COLOR_FOREGROUND

This field specifies the color type for use with getColor method. This field specifies the foreground color, for text characters and simple graphics on the screen.

• public static final  int COLOR_HIGHLIGHTED_BACKGROUND

This field specifies the color type for use with getColor method. This field specifies the color for the focus or focus highlight, when it is drawn as a filled in rectangle.

• public static final  int COLOR_HIGHLIGHTED_BORDER

This field specifies the color type for use with getColor method. This field specifies the color for boxes and borders when the object is to be drawn in a highlighted state.

• public static final  int COLOR_HIGHLIGHTED_FOREGROUND

This field specifies the color type for use with getColor method. This field specifies the color for text characters and simple graphics when they are highlighted.

• public static final  int LIST_ELEMENT

This field represents the Image type for List element image.

o    Methods

·         public void callSerially(Runnable r)

This method causes the r (Runnable object) to have its run () method called later, serialized with the event stream soon after the completion of repaint cycle.

• public boolean flashBacklight(int duration)

This method requests a flashing effect for the device’s backlight. This method is quite useful in games and can be used to attract the user’s attention or as a special effect for games.

• public int getBestImageHeight(int imageType)

This method returns the best image height for the image type. The return value may be zero if there is no best size. The return value will never be negative.

• public int getBestImageWidth(int imageType)

This method returns the best image width for the image type. The return value may be zero if there is no best size. The return value will never be negative.

• public int getBorderStyle(boolean highlighted)

This method returns the stroke style for drawing the border. This method will return either of the following:

·   Graphics.DOTTED

·   Graphics.SOLID

• public int getColor(int colorSpecifier)

This method returns specified kind of color from high level user interface color scheme in the form of 0x00RRGGBB.

• public Displayable getCurrent()

This method returns the MIDlet's current Displayable object

• public static Display getDisplay(javax.microedition.midlet.MIDlet m)

This method returns the display object that application can use for its user interface.

• public boolean isColor()

This method returns true if the display supports color else it will return false.

• public int numAlphaLevels()

This method returns number of alpha transparency levels supported. This method will at least return a value of 2 which stands for full transparency and full opacity. In case alpha blending is supported this value will be greater than 2.

• public int numColors()

This method returns number of colors a device can support. If the isColor () method has returned false then this method will give the number of grayscale values this device supports.

• public void setCurrent(Alert alert, Displayable nextDisplayable)

This method requests that this Alert be made current Displayable and that next Displayable be made current after the Alert is dismissed.

• public void setCurrent(Displayable nextDisplayable)

This method requests that a different Displayable object shall be made visible on the display.

• public void setCurrentItem(Item item)

This method requests that the Displayable that contains this Item be made current. This method scrolls the Displayable so that this Item is visible and if possible assigns the focus to the Item passed in the argument.

• public boolean vibrate(int duration)

This method is used for vibrating the device for a specified number of milliseconds. If we want to switch off the vibrator then we should pass 0 in the argument for this method. This method returns true if the vibrator can be controlled by the application and this display is in the foreground else it returns false. 

public abstract class Displayable

What is it?

Any class which needs to be placed on the display should be a sub class of this class. A Displayable object may have the following:

·   Title

·   Ticker

·   Zero or more commands

·    A command listener associated with it.

The sub classes of this class define the contents to be displayed and their interaction with the users.

o    Methods

·         public void addCommand(Command cmd)

This method adds the specified command to the Displayable. One command can not be added more than once on a Displayable even by calling this method repeatedly.

• public int getHeight()

This method returns height of the area available to the application.

• public Ticker getTicker()

This method returns ticker object used. This method returns a null value if no ticker is present in this Displayable.

• public java.lang.String getTitle()

This method returns the title. It returns a null if no title is there.

• public int getWidth()

This method returns width of the area available to the application.

• public boolean isShown()

This method returns true if this Displayable is currently visible.

• public void removeCommand(Command cmd)

This method removes the specified command from the Displayable. If the same command is repeatedly removed from the Displayable this method will have no effect.

• public void setCommandListener(CommandListener l)

This method sets a listener for Commands to this Displayable, replacing any previous CommandListener.

• public void setTicker(Ticker ticker)

This method sets a ticker for use with this Displayable. In the process it removes any previous ticker.

• public void setTitle(String s)

This method sets the title of the Displayable. If null is given is the argument this method removes the title.

• protected void sizeChanged(int w, int h)

The implementation calls the sizeChanged (int w, int h) method when the available area of the Displayable has changed.

public final class Font

What is it?

One peculiar feature of MIDP 1.0 as well as MIDP 2.0 is that applications can not create there own fonts. The application can only demand particular kind of fonts and if they are there on the device they will returned. If the desired font is not there an approximate match is returned. This class is used to represent fonts and font metrics.

o    Fields

• public static final  int FONT_INPUT_TEXT

This field specifies a Font to be used to draw text input by a user.

Value: 1.

• public static final  int FONT_STATIC_TEXT

This field specifies a default Font to be used to draw Item and Screen contents.

Value: 0

o    Methods

• public static Font getFont(int fontSpecifier)

This method returns font that corresponds to the Font passed in the argument.

public class Form

What is it?

The Form contains an arbitrary mixture of items namely:

·   Images

·   Read-only text fields

·   Editable text fields

·   Editable date fields

·   Gauges

·   Choice groups

·   Custom items.

o    Methods

• public void deleteAll()

This method deletes all the items from this Form leaving it without any items.

• public int getHeight()

This method returns the height of the displayable area of the Form in pixels.

• public int getWidth()

This method returns the width of the Form in pixels.

public class Gauge

What is it?

This item shows an integer value in a graphical display. Some devices implement it in form of a bar graph while other show it as a progress screen.

o    Fields

• public static final  int CONTINUOUS_IDLE

This field represents the continuous idle state of a non-interactive Gauge with an indefinite range.

• public static final  int CONTINUOUS_RUNNING

This field represents the continuous running state of a non-interactive Gauge with an indefinite range.

• public static final  int INCREMENTAL_IDLE

This field represents the incremental idle state of a non-interactive Gauge with indefinite range.

• public static final  int INCREMENTAL_UPDATING

This field represents the incremental updating state of a non-interactive Gauge with indefinite range.

• public static final  int INDEFINITE

This field represents a special value used for the maximum value in order to indicate that the Gauge has indefinite range.

public class Graphics

What is it?

This class acts as a pen/brush for drawing. It provides us with a simple 2D geometric rendering capability.

o    Fields

• public static final  int BASELINE

This field is the constant for positioning the anchor point at the baseline of text.

• public static final  int BOTTOM

This field is the constant for positioning the anchor point of text and images below the text or mage.

• public static final  int DOTTED

This field is the constant for the DOTTED stroke style.

• public static final  int HCENTER

This field is the constant for centering text and images horizontally around the anchor point.

• public static final  int LEFT

This field is the constant for positioning the anchor point of text and images to the left of the text or image.

• public static final  int RIGHT

This field is the constant for positioning the anchor point of text and images to the right of the text or image.

• public static final  int SOLID

This field is the constant for the solid stroke style.

• public static final  int TOP

This field is the constant for positioning the anchor point of text and images above the text or image.

• public static final  int VCENTER

This field is the constant for centering images vertically around the anchor point.

 o    Methods

• public void copyArea(int x_src, int y_src, int width, int height, int x_dest, int y_dest, int anchor)

This method copies the contents of a rectangular area (given by first 4 co-ordinates) to a destination area whose anchor point identified by the variable anchor is located at the variables represented by ‘x_dest’ and ‘y_dest’.

• public void drawRegion(Image src, int x_src, int y_src, int width, int height, int transform, int x_dest, int y_dest, int anchor)

This method copies a region of the specified source image to a location within the destination, possibly transforming (rotating and reflecting) the image data using the chosen transform function.

• public void drawRGB(int[] rgbData, int offset, int scanlength, int x, int y, int width, int height, boolean processAlpha)

This method renders a series of device-independent color values in a specified region. The values are stored in the integer array ‘rgbData’ in a format with 24 bits of RGB and an eight-bit alpha value (0xAARRGGBB), with the first value stored at the specified offset.

• public void fillTriangle(int x1, int y1, int x2, int y2, int x3, int y3)

This method is used for drawing filled rectangles. This method fills the specified triangle will the current color. The lines connecting each pair of points are included in the filled triangle.

• public int getDisplayColor(int color)

This method returns the corresponding color that will be displayed on the device’s screen (in 0x00RRGGBB format). This method is useful as the programmer can determine the actual drawing color that will be used due to the device constraints instead of the color he/she has given as the current color.

public class Image

What is it?

The Image class is used to hold graphical image data. This class holds the data in off-screen memory and it is not painted in the Display till an explicit call is not made to display it either by low level user interface classes like Canvas or high level user interface classes like the Form

o    Methods

• public static Image createImage(Image image, int x, int y, int width, int height, int transform)

This method returns the created image from the specified co-ordinate area of the source image and suitably transforms it according to the transform parameter.

• public static Image createImage(java.io.InputStream stream)

This method returns the created image from the decoded data obtained from an InputStream.

• public static Image createRGBImage(int[] rgb, int width, int height, boolean processAlpha)

This method returns the created image from a sequence of ARGB values.

• public void getRGB(int[] rgbData, int offset, int scanlength, int x, int y, int width, int height)

This method obtains ARGB pixel data from the specified region of this image and stores it in the array of integers provided in the method signature.

public class ImageItem

What is it?

ImageItem is an item that can contain an image.

o    Constructors

• public ImageItem(String label, Image image, int layout, String altText, int appearanceMode)

Creates a new ImageItem object with the given label, image, layout directive, alternate text string, and appearance mode. Either label or alternative text may be present or null.

o    Methods

• public int getAppearanceMode()

This method returns the appearance mode value which can be one of the following values: Item.PLAIN, Item.HYPERLINK or Item.BUTTON

public abstract class Item

What is it?

This is the super class for all the components that can be added to a Form

o    Field

• public static final  int BUTTON

A field which stands for an appearance mode value indicating that the Item is to appear as a button.

• public static final  int HYPERLINK

A field which stands for an appearance mode value indicating that the Item is to appear as a hyperlink.

• public static final  int LAYOUT_2

A field which stands for a layout directive indicating that new MIDP 2.0 layout rules are in effect for this Item. If this bit is clear it indicates that MIDP 1.0 layout behavior applies to this Item.

• public static final  int LAYOUT_BOTTOM

A field which stands for a layout directive indicating that this Item should have a bottom-aligned layout.

• public static final  int LAYOUT_CENTER

A field which stands for a layout directive indicating that this Item should have a horizontally centered layout.

• public static final  int LAYOUT_DEFAULT

A field which stands for a layout directive indicating that this Item should follow the default layout policy of its container.

• public static final  int LAYOUT_EXPAND

A field which stands for a layout directive indicating that this Item's width may be increased to fill available space.

• public static final  int LAYOUT_LEFT

A field which stands for a layout directive indicating that this Item should have a left-aligned layout.

• public static final  int LAYOUT_NEWLINE_AFTER

A field which stands for a layout directive indicating that this Item should the last on its line or row, and that the next Item (in case there is any) in the container should be placed on a new line or row.

• public static final  int LAYOUT_NEWLINE_BEFORE

A field which stands for a layout directive indicating that this Item should be placed at the beginning of a new line or row.

• public static final  int LAYOUT_RIGHT

A field which stands for a layout directive indicating that this Item should have a right aligned layout.

• public static final  int LAYOUT_SHRINK

A field which stands for a layout directive indicating that this Item's width may be reduced to its minimum width.

• public static final  int LAYOUT_TOP

A field which stands for a layout directive indicating that this Item should have a top aligned layout.

• public static final  int LAYOUT_VCENTER

A field which stands for a layout directive indicating that this Item should have a vertically centered layout.

• public static final  int LAYOUT_VEXPAND

A field which stands for a layout directive indicating that this Item's height may be increased to fill available space.

• public static final  int LAYOUT_VSHRINK

A field which stands for a layout directive indicating that this Item's height may be reduced to its minimum height.

• public static final  int PLAIN

This field indicates that the item should have a normal appearance.

o    Methods

·         public void addCommand(Command cmd)

This method adds a context sensitive Command to the item.

• public int getLayout()

This method returns a combination of layout directive values

• public int getMinimumHeight()

This method returns the minimum height of this item.

• public int getMinimumWidth()

This method returns the minimum width of this item.

• public int getPreferredHeight()

This method returns the preferred height of this Item.

• public int getPreferredWidth()

This method returns the preferred width of this Item.

• public void notifyStateChanged()

This method causes this Item's containing Form to notify the Item's ItemStateListener.

• public void removeCommand(Command cmd)

This method removes the context sensitive command from this item.

• public void setDefaultCommand(Command cmd)

This method sets default Command for this Item.

• public void setItemCommandListener(ItemCommandListener l)

This method sets a listener for Commands to this Item replacing any previous ItemCommandListener.

• public void setLayout(int layout)

This method sets the layout directives for this item.

• public void setPreferredSize(int width, int height)

This method sets the preferred width and height for this Item.

public interface ItemCommandListener

What is it?

This is a new form of event listener which has been introduced in MIDP 2.0 for receiving notification of commands that have been invoked on Item objects.

o    Methods

·         public void commandAction(Command c, Item item)

This method is called by the system to indicate that a command has been invoked on a specific item. 

public class List

What is it?

List is a Screen containing list of choices. This class gives us a very good user interface element for situation where a user has to choose between different choices or choose some elements among many. An example of an application where a list can be particularly useful is a restaurant menu application where a user can choose items to order for home delivery.

o    Methods

• public int getFitPolicy()

This method gets the application’s preferred policy for fitting Choice element contents to the available screen space.

• public Font getFont(int elementNum)

This method returns the preferred font to use to render the specified element.

• public void removeCommand(Command cmd)

This method overrides the removeCommand method in Displayable.

• public void setFitPolicy(int fitPolicy)

This method sets the application’s preferred policy for fitting Choice element contents to the available screen space.

• public void setFont(int elementNum, Font font)

This method sets the application’s preferred font for rendering the specified element of this Choice.

• public void setSelectCommand(Command command)

This method sets the Command to be used for an IMPLICIT List selection action. This method will have no effect for other types of Lists. Setting a null value is allowed. The command should be null only if you want to have no select command for the List.

public abstract class Screen

What is it?

Screen is the common super class of all high-level user interface classes. The contents that are displayed and their interaction with the user are defined by subclasses of Screen. In MIDP 2.0 the 4 methods of Screen that were there in MIDP 1.0 have been shifted to Displayable.

public class Spacer

What is it?

A Spacer is a blank, non-interactive item that has a settable minimum size.

o    Constructors

·         public Spacer(int minWidth, int minHeight)

This constructor creates a new Spacer with the given minimum size.

o    Methods

·         public void addCommand(Command cmd)

Spacers can not contain Commands. Therefore this method will always throw IllegalStateException whenever it is called for a Spacer.

• public void setDefaultCommand(Command cmd)

Spacers can not contain Commands. Therefore this method will always throw IllegalStateException whenever it is called for a Spacer.

• public void setLabel(String label)

Spacers can not contain labels. Therefore this method will always throw IllegalStateException whenever it is called for a Spacer.

• public void setMinimumSize(int minWidth, int minHeight)

This method sets the minimum size for this spacer. The Form will not be allowed to make the Spacer smaller than this size. The minimum size of Spacer must be zero or greater.

To do List

public class StringItem

What is it?

o    Constructors

• public StringItem(String label, String text, int appearanceMode)

This constructor is a new edition in MIDP 2.0. It creates a new object with the given label, textual content and appearance mode. The label or text elements may be present or they may have null value.

o    Methods

·         public int getAppearanceMode()

This method returns the appearance mode value. The value may be one of the following:

·   Item.PLAIN

·   Item.HYPERLINK

·   Item.BUTTON

• public Font getFont()

This method returns the preferred font of the application that will be used to render this StringItem

• public void setFont(Font font)

This method sets the application’s preferred font for rendering this StringItem.

public class TextBox

What is it?

The TextBox class is a Screen that allows the user to enter and edit text.

o    Methods

• public void setInitialInputMode(String characterSubset)

This method sets a hint to the implementation as to the input mode that should be used when the user initiates editing of this TextBox.

public class TextField

What is it?

 A TextField is an editable text component that may be placed into a Form. 

o    Fields

• public static final  int DECIMAL

When you use this field the user is allowed to enter numeric values with optional decimal fractions.

• public static final  int INITIAL_CAPS_SENTENCE

This flag is a hint to the implementation that during text editing of the contents of TextField the initial letter of each sentence should be capitalized.

• public static final  int INITIAL_CAPS_WORD

This flag is a hint to the implementation that during text editing of the contents of TextField the initial letter of each word should be capitalized.

• public static final  int NON_PREDICTIVE

This field indicates that the text entered by the user would not consist of words that are likely to be found in dictionaries typically used by predictive input schemes.

• public static final  int SENSITIVE

This field indicates that the text entered is sensitive data. The device must never store into a dictionary or table for use in predictive, auto-completing or other accelerated input schemes. A security ID is an example of sensitive data.

• public static final  int UNEDITABLE

This field indicates that editing is currently disallowed. When this flag is set the device will prevent the user from changing the text contents of this object.

o    Methods

• public void setInitialInputMode(String characterSubset)