BlackBerry

Developers

Richard Evers, Editor

Most applications can be written using a fairly common subset of the available API. To follow is a brief tutorial on the most commonly used methods from the BlackBerry and MIDP APIs.

Package	Class	Method
javax.microedition.io	Connector	open
net.rim.device.api.ui.component	DateField	( constructor )
net.rim.device.api.ui.component	DateField	GetDate
net.rim.device.api.ui.component	DateField	SetEditable
net.rim.device.api.ui.component	Dialog	Alert
net.rim.device.api.ui.component	Dialog	Ask
net.rim.device.api.ui.component	EditField	( constructor )
net.rim.device.api.ui.component	EditField	SetEditable
net.rim.device.api.ui.component	EditField	SetFilter
net.rim.device.api.ui	Graphics	DrawText
net.rim.device.api.ui	Graphics	DrawPoint
net.rim.device.api.ui	Graphics	getScreenWidth
net.rim.device.api.ui	Graphics	SetColor
net.rim.device.api.system	KeyListener	KeyDown
net.rim.device.api.system	KeyListener	KeyRepeat
net.rim.device.api.system	KeyListener	KeyStatus
net.rim.device.api.system	KeyListener	KeyUp
net.rim.device.api.ui.component	LabelField	( constructor )
net.rim.device.api.ui.container	MainScreen	NextFocus
net.rim.device.api.ui	MenuItem	( constructor )
net.rim.device.api.ui.component	ObjectChoiceField	( constructor )
net.rim.device.api.ui.component	ObjectChoiceField	setChangeListener
net.rim.device.api.ui.component	ObjectChoiceField	getChoice
net.rim.device.api.ui.component	ObjectChoiceField	setChoices
net.rim.device.api.ui.component	ObjectChoiceField	setSelectedIndex
net.rim.device.api.ui.component	ObjectChoiceField	getSize
net.rim.device.api.util	Persistable
javax.microedition.rms	RecordStore	addRecord
javax.microedition.rms	RecordStore	closeRecordStore
javax.microedition.rms	RecordStore	deleteRecordStore
javax.microedition.rms	RecordStore	enumerateRecords
javax.microedition.rms	RecordStore	openRecordStore
net.rim.device.api.i18n	ResourceBundle	getBundle
net.rim.device.api.i18n	ResourceBundle	getString
net.rim.device.api.system	TrackwheelListener	trackWheelClick
net.rim.device.api.system	TrackwheelListener	trackWheelRoll
net.rim.device.api.system	TrackwheelListener	trackWheelUnclick
net.rim.device.api.ui	UiApplication	enterEventDispatcher
net.rim.device.api.ui	UiApplication	getActiveScreen
net.rim.device.api.ui	UiApplication	getUiApplication
net.rim.device.api.ui	UiApplication	invokeLater
net.rim.device.api.ui	UiApplication	PopScreen
net.rim.device.api.ui	UiApplication	pushScreen

javax.microedition.io.Connector.open()

Description:

Basic type of generic connection.
Used to create and open most connection types including HTTP, SMS and file.

Syntax:

public static Connection open(String URL)

Parameter:

URL: connection string

Returns:

new Connection object

Throws:

IllegalArgumentException if a parameter is invalid
ConnectionNotFoundException if connection not found
IOException if some other kind of I/O error occurs

Example:

public static final String httpURL = "http://www.mywebsite.com";
HttpConnection http = null;

synchronized(this) {
    try {
        //create an HTTP connection with
        // an InputStream
        http = (HttpConnection)Connector.open(httpURL);
        http.setRequestMethod(HttpConnection.POST);

net.rim.device.api.ui.component.DateField()

Description:

Constructs a new DateField instance with label, initial value, and format.

Syntax:

public DateField
(
    String field_label,
    long initial_date,
    DateFormat format
)

Parameters:

Field Label
Initial date value
Format to specify how the value looks: DATE (year, month, day) TIME (hour, minute, second) DATE_TIME (yr, month, day, hour, min, sec)

Returns:

DateField

Example:

// set date
long date = _receipt.getDateAsLong();

if ( date == 0 )
    date = Calendar.getInstance().getTime().getTime();

_dateField = new DateField(_resources.getString(EXP_DATE), date,DateField.DATE);

net.rim.device.api.ui.component.DateField.getDate()

Description:

Retrieves the absolute value of field in ticks
Returns number of milliseconds since the epoch (midnight Jan 1, 1970) represented by field's date

Syntax:

public long getDate()

Parameter:

void

Returns:

If time represented in field, returns value between 0 and (24*60*60*1000)
If field's value is unspecified, returns Long.MIN_VALUE

Example:

private boolean saveSettings() {
    _receipt.setDate(_dateField.getDate());

net.rim.device.api.ui.component.DateField.setEditable()

Description:

Sets editable state of field
Overrides setEditable in class Field

Syntax:

public void setEditable(boolean editable)

Parameter:

editable (true == editable, false == read only)

Returns:

void

Example:

_dateField.setEditable(true);
add(_dateField);

net.rim.device.api.ui.component.Dialog.alert()

Description:

Creates an alert dialog
Uses an exclamation mark bitmap

Syntax:

public static void alert(String message)

Parameter:

Text message to display in the alert

Returns:

void

Example:

Dialog.alert(_resources.getString(ERROR_CONNECTION));

net.rim.device.api.ui.component.Dialog.ask()

Description:

Creates a standard inquiry dialog
Uses a question mark bitmap

Syntax:

public static int ask(int type)

Parameter:

Standard inquiry dialog type:

  D_OK
  D_SAVE
  D_DELETE
  D_YES_NO

Returns:

Integer set as follows:

  Dialog.SAVE
  Dialog.CANCEL
  Dialog.DISCARD

Example:

int response = Dialog.ask(Dialog.D_SAVE);

if (Dialog.SAVE == response ||  Dialog.CANCEL == response)
    return false;

if ( Dialog.DISCARD == response )
    _report.deleteReceipt(_receiptId);

net.rim.device.api.ui.component.EditField()

Description:

Builds an Field.EDITABLE edit field with a specified label and initial contents that can hold up to BasicEditField.DEFAULT_MAXCHARS characters

Syntax:

public EditField(String label, String initialValue)

Parameters:

Field label
Initial text value to show in field

Returns:

EditField

Example:

private void addFields() {
    _emailField = new EditField(_resources.getString( FIELD_USER_EMAIL ),_reportDatastore.getUserEmail());

net.rim.device.api.ui.component.EditField.setEditable()

Description:

Set editable state of field
Change style by adding or removing EDITABLE style
Method inherited from class net.rim.device.api.ui.Field

Syntax:

public void setEditable(boolean editable)

Parameter:

editable == True then make field editable
editable == False then make non-editable

Returns:

void

Example:

_emailField.setEditable(true);
add(_emailField);

net.rim.device.api.ui.component.EditField.setFilter()

Description:

Sets the text filter for field
Method inherited from class net.rim.device.api.ui.component.BasicEditField

Syntax:

public void setFilter(TextFilter filter)

Parameter:

Text filter for field:

  DEFAULT
  EMAIL
  HEXADECIMAL
  INTEGER
  LOWERCASE
  NUMERIC
  PHONE
  UPPERCASE
  URL

Returns:

void

Example:

_emailField = new EditField(_resources.getString(FIELD_USER_EMAIL), _reportDatastore.getUserEmail());
_emailField.setFilter(EMAIL);

net.rim.device.api.ui.Graphics.drawText()

Description:

Use to draw a text character
Renders character's glyph using default font
Crops to fit if glyph too large for current clipping region

Syntax:

public int drawText(char character, int x, int y, int flags, int width)

Parameters:

Character to draw
Horizontal (x) and Vertical (y) positions of drawing anchor
Combination of constant drawing position flags
Width, in pixels, of region available for drawing

Returns:

Glyph block width in pixels including width of clipped pixels

Example:

public void paint( Graphics graphics, int yPos ) {
    int xpos = 0;
    int n = _spaces.length;

    for (int i = 0; i < n; ++i) {
        graphics.drawText( _texts[i], xpos, yPos, graphics.ELLIPSIS, _spaces[i] );
        xpos += _spaces[i];

        if (i < n - 1)
            xpos += _buffer;
    }
}

net.rim.device.api.ui.Graphics.drawPoint()

Description:

Draws a pixel at passed coordinate

Syntax:

public void drawPoint(int x, int y)

Parameters:

Horizontal (x) position of the point to draw
Vertical (y) position of the point to draw

Returns:

void

Example:

// p
le
// this gives us a greyed out effect.
protected void subpaint(Graphics graphics) {
    super.subpaint(graphics);

    if (!_focusable) {
        graphics.setColor(Graphics.WHITE);
        int w = getWidth();
        int h = getHeight();

        for (int i=0; i < w ;++i) {
            for (int c=0; c < h; ++c) {
                if ((i+c)%2 == 0 ) {
                    graphics.drawPoint(i,c);
                }
            }
        }
        graphics.setColor(Graphics.BLACK);
    }
}

net.rim.device.api.ui.Graphics.SetColor()

Description:

Sets the current color
All subsequent rendering done in displayable color nearest to specified color

Syntax:

public void setColor(int RGB)

Parameter:

RGB color to use, of the form 0x00RRGGBB

Returns:

void

Example:

protected void subpaint(Graphics graphics) {
    super.subpaint(graphics);

    if (!_focusable) {
        graphics.setColor(Graphics.WHITE);
        int w = getWidth();
        int h = getHeight();

        for (int i=0; i < w ;++i) {
            for (int c=0; c < h; ++c) {
                if ((i+c)%2 == 0 ) {
                    graphics.drawPoint(i,c);
                }
            }
        }

        graphics.setColor(Graphics.BLACK);
    }
}

net.rim.device.api.ui.Graphics.getScreenWidth()

Description:

Retrieves total drawing width of the screen

Syntax:

public static int getScreenWidth()

Parameter:

void

Returns:

Width in pixels of the device screen's drawable area

Example:

public int getPreferredWidth( ListField listField) {
    return Graphics.getScreenWidth();
}

net.rim.device.api.system.KeyListener.keyDown()

Description:

Invoked when a key has been pressed.
Using Keypad.key(keycode) gets the key pressed; alphabetic keys are always upper case.
Using keypad.status(keycode) gets the modifier key status at the time of the keypress.
Applications such as games will want to use this function as it provides information about which key was actually pressed, regardless of locale and any key mappings applied.

Syntax:

public boolean keyDown( int keycode, int time )

Parameters:

Key scan code of the character before any effects of the ALT or SHIFT keys
Number of milliseconds since the device was turned on

Returns:

True if the event was consumed

Example:

public boolean keyDown(int keycode,int time) {
    return false;
}

net.rim.device.api.system.KeyListener.keyRepeat()

Description:

Invoked when a key has been repeated
Similar to keyDown

Syntax:

public boolean keyRepeat( int keycode, int time )

Parameters:

Key scan code before effects of ALT or SHIFT keys
Number of milliseconds since device was turned on

Returns:

True if event was consumed

Example:

public boolean keyRepeat( int keycode, int time ) {
    return false;
}

net.rim.device.api.system.KeyListener.keyStatus()

Description:

Invoked when ALT or SHIFT status has changed

Syntax:

public boolean keyStatus( int keycode, int time )

Parameters:

Key scan code before effects of ALT or SHIFT keys
Number of milliseconds since device was turned on

Returns:

True if event was consumed

Example:

public boolean keyStatus( int keycode, int time ) {
    return false;
}

net.rim.device.api.system.KeyListener.keyUp()

Description:

Invoked when a key has been released
Events are disabled by default for performance reasons and must be explicitly enabled via Application.enableKeyUpEvents(boolean)

Syntax:

public boolean keyUp( int keycode, int time )

Parameters:

Key scan code before effects of ALT or SHIFT keys
Number of milliseconds since device was turned on

Returns:

True if event was consumed

Example:

public boolean keyUp( int keycode, int time ) {
    return false;
}

net.rim.device.api.ui.component.LabelField()

Description:

Constructs a new LabelField instance with initial text

Syntax:

public LabelField(Object text)

Parameter:

Label text: can be a String, StringBuffer, char[] or byte[] and may be null for an empty label

Returns:

void

Example:

// Constructs a new ReportScreen object,
// and populates the screen with all the
// available information
public ReportScreen(ReportDataStore rds) {
    _reportDatastore = rds;
    setTitle(new LabelField(_resources.getString(TITLE_MAIN)));

    _list = new ListField();
    _list.setCallback(new CallBack());

    // add the list field to the screen
    add(_list);

net.rim.device.api.ui.container.MainScreen.nextFocus()

Description:

Returns index of the next field to be given focus
Called by framework during TW (track wheel) focus move operation
Method inherited from class net.rim.device.api.ui.Manager

Syntax:

protected int nextFocus(int direction, boolean alt)

Parameters:

Direction focus is moving within field (+1 forward, -1 back)
True if ALT-rolling the trackwheel else false

Returns:

Index of next field to have focus (-1 to exit)

Throws:

IllegalArgumentException if direction parm != 1 or -1

Example:

import net.rim.device.api.ui.container.*;
import net.rim.device.api.ui.*;

abstract class MainScreenWithMenus extends MainScreen {
    abstract public MenuItem[] getMenuItems();

    public int nextFocus( int direction, boolean alt ) {
        return super.nextFocus(direction, alt);
    }
}

net.rim.device.api.ui.MenuItem()

Description:

Constructs a new MenuItem

Syntax:

public MenuItem( ResourceBundle bundle, int id, int ordinal, int priority )

Parameters:

Resource bundle to support internationalization
Menu item ID / key value for menu item's associated resource bundle string
Ordering parameter, lower values towards top of menu
Priority of menu item

Returns:

void

Example:

menuItems[index++] = new MenuItem( _resources, MENUITEM_CLOSE, 200000, 20000 ) {
    public void run() {
        if (exit()) {
            ((ExpenseScreen)UiApplication.getUiApplication().getActiveScreen()).exit();
        }
    }
};

net.rim.device.api.ui.component.ObjectChoiceField()

Description:

Builds a new object choice field, and sets the initially selected value based on index parameter
If passed array is null then method ignores index parameter and sets initially selected index to zero

Syntax:

public ObjectChoiceField( String label, Object[] choices, int initialIndex )

Parameters:

Field label
Field choices - if null, empty object choice field is created
Index of the initially selected value

Returns:

void

Example:

private int _currentType;

private void initTypeChoices() {
    _typeChoices = new String[6];
    _typeChoices[Receipt.MEALS] = "Expense Type Meals";
    ...
}

_typeField = new ObjectChoiceField( _resources.getString(FIELD_EXPENSE_TYPE), _typeChoices, _currentType );

net.rim.device.api.ui.component.ObjectChoiceField.getChoice()

Description:

Retrieves object by index
Overrides getChoice in class ChoiceField

Syntax:

public Object getChoice(int index)

Parameter:

Index position in list of object you wish to retrieve

Returns:

Object at the index you specify

Throws:

IllegalArgumentException

Example:

// cannot use
// ChoiceField.setSelectedIndex(Object)
// because it does not invalidate the field
private int getChoiceIndex(ObjectChoiceField field, Object obj) {
    for (int i=field.getSize()-1;i>=0;--i) {
        if (field.getChoice(i).equals(obj))
            return i;
    }
    return -1;
}

net.rim.device.api.ui.component.ObjectChoiceField.setSelectedIndex()

Description:

Sets the currently chosen value

Syntax:

public void setSelectedIndex(int index)

Parameter:

Index of the selected value

Returns:

void

Throws:

IllegalArgumentException if index is out of bounds

Example:

switch (f.getSelectedIndex()) {
    case Receipt.MILEAGE:
        _gvf.setFocusable(false);

    case Receipt.HOTEL:
    case Receipt.TRANSPORTATION: {
        int index = getChoiceIndex(_glField, otherChoice);

        if (index != -1)
            _glField.setSelectedIndex(index);
        break;
 }

net.rim.device.api.ui.component.ObjectChoiceField.getSize()

Description:

Retrieves number of choices in field

Syntax:

public int getSize()

Parameter:

void

Returns:

Number of choice values in field's list

Example:

// cannot use
// ChoiceField.setSelectedIndex(Object)
// because it does not invalidate the field
private int getChoiceIndex(ObjectChoiceField field, Object obj) {
    for (int i=field.getSize()-1;i>=0;--i) {
        if (field.getChoice(i).equals(obj))
            return i;
    return -1;
}

net.rim.device.api.ui.component.ObjectChoiceField.setChangeListener()

Description:

Specifies a listener for field changes
Method inherited from class net.rim.device.api.ui.Field
Each field can have only one change listener object
To provide a new change listener for a field, first invoke setChangeListener(null)

Syntax:

public void setChangeListener(FieldChangeListener listener)

Parameter:

Object to listen for field changes

Returns:

void

Throws:

IllegalStateException when listener already set and !null

Example:

ChoiceFieldListener CFL = new ChoiceFieldListener();
...
_glField.setChangeListener(CFL);

net.rim.device.api.ui.component.ObjectChoiceField.setChoices()

Description:

Provides a new list of choices for field
Selected choice reset to first value in the list

Syntax:

public void setChoices(Object[] choices)

Parameter:

New list of choices for field

Returns:

void

Example:

public void refresh() {
    // an existing receipt
    if (_receiptId>=0) {
        if (_receipt.getGLCode() !=_glField.getChoice(0)) {
            _glField.setChoices(getListAsArray(_glCodeList, _receipt.getGLCode()));
        }
    }
}

javax.microedition.rms.RecordStore.addRecord()

Description:

Adds a new record to persistent storage before returning

Syntax:

public int addRecord(byte[] data, int offset, int numBytes)

Parameters:

Data to be stored in record: null for no data
Index into data buffer of first relevant byte for record
Number of bytes of data buffer to use for record (>=0)

Returns:

recordId for new record

Throws:

RecordStoreNotOpenException if record store is not open
RecordStoreException if related exception occurred
RecordStoreFullException if has no more room

Example:

try {
    // open the rms, add the record,
    // and close the rms
    RecordStore rms = RecordStore.openRecordStore( name, true );

    rms.addRecord(data, _start, data.length);
    rms.closeRecordStore();
} catch (Exception e) {

javax.microedition.rms.RecordStore.closeRecordStore()

Description:

Called when MIDlet requests record store closure
Not closed until closeRecordStore() count equals openRecordStore() count
All listeners removed on close

Syntax:

public void closeRecordStore()

Parameter:

void

Returns:

void

Throws:

RecordStoreNotOpenException if record store is not open.
RecordStoreException if related exception occurred

Example:

try {
    RecordStore rms = RecordStore.openRecordStore(name, true);
    RecordEnumeration enum = rms.enumerateRecords(null,null, false );

    if (enum.hasNextElement())
        result = enum.nextRecord();
    else
        result = null;

    rms.closeRecordStore();
    enum.destroy();
} catch (Exception e) {

javax.microedition.rms.RecordStore.deleteRecordStore()

Description:

Deletes named record store
MIDlet suites only allowed to operate on their own record stores, including deletions

Syntax:

public static void deleteRecordStore(String recStoreName)

Parameter:

The MIDlet suite unique record store to delete

Returns:

void

Throws:

RecordStoreNotOpenException if record store is not open.
RecordStoreException if related exception occurred

Example:

static boolean save( byte[] data, String name ) {
    try {
        RecordStore.deleteRecordStore(name);
    } catch (RecordStoreException rse) {
}

javax.microedition.rms.RecordStore.enumerateRecords()

Description:

Returns an enumeration for traversing a set of records in the record store in an optionally specified order
The filter, if non-null, is used to determine what subset of the record store records will be used
If both the filter and comparator are null, enumeration will traverse all records in the store in an undefined order

Syntax:

public RecordEnumeration enumerateRecords( RecordFilter filter, RecordComparator comparator, boolean keepUpdated )

Parameters:

RecordFilter is an interface with one method, boolean matches(byte[] candidate)
RecordComparator is an interface with one method, int compare(byte[] rec1, byte[] rec2)
The keepUpdated parameter tells whether the enumeration has to keep track of inserts and deletes that happen while the enumeration is open

Returns:

All records for which the filter returns true, in the order defined by the RecordComparator

Throws:

RecordStoreNotOpenException if record store is not open

Example:

try {
    RecordStore rms = RecordStore.openRecordStore(name, true);
    RecordEnumeration enum = rms.enumerateRecords(null,null, false );

    if (enum.hasNextElement())
        result = enum.nextRecord();
    else
        result = null;

    rms.closeRecordStore();
    enum.destroy();
} catch (Exception e) {

javax.microedition.rms.RecordStore.openRecordStore()

Description:

Open/Create a record store associated with MIDlet suite

Syntax:

public static RecordStore openRecordStore( String recordStoreName, boolean createIfNecessary )

Parameters:

MIDlet suite unique name (max 32 char length)
If true, record store will be created if necessary

Returns:

If method called when record store is already open by a MIDlet in the MIDlet suite, returns a reference to the same object

Throws:

RecordStoreException if a record store-related exception occurred
RecordStoreNotFoundException if record store could not be found
RecordStoreFullException if record store is full

Example:

try {
    RecordStore rms = RecordStore.openRecordStore(name, true);

    RecordEnumeration enum = rms.enumerateRecords(null,null, false );

    if (enum.hasNextElement())
        result = enum.nextRecord();
    else
        result = null;

    rms.closeRecordStore();
    enum.destroy();
} catch (Exception e){

net.rim.device.api.i18n.ResourceBundle.getBundle()

Description:

Retrieve resource bundle family with bundle ID
Creates new family with ID and name if necessary

Syntax:

public static final ResourceBundleFamily getBundle(long bundle, String name)

Parameters:

Bundle ID
Name for the resource bundle family

Returns:

Resource bundle family of provided ID

Throws:

IllegalArgumentException if name or its hash is not valid

Example:

public static MenuItem _closeMenuItem;
private static ResourceBundle _resources;

static {
    //Resources for the project
    _resources = ResourceBundle.getBundle(BUNDLE_ID, BUNDLE_NAME);

    // Close Menu Item
    _closeMenuItem = new MenuItem( _resources, MENUITEM_BACK, 200000, 10 ) {
        public void run() {
            UiApplication uiApp = UiApplication.getUiApplication();
            UiApplication.getUiApplication().popScreen(uiApp.getActiveScreen());
    }
};

net.rim.device.api.i18n.ResourceBundle.getString()

Description:

Retrieves string form of resource object by key
Method casts return value of getObject(int) as a String

Syntax:

public final String getString(int key)

Parameter:

Key for searched-for resource object

Returns:

String form of resource object

Throws:

MissingResourceException if neither bundle nor any enclosing parent bundle contains resource associated with provided key

Example:

private static String[] _ccStartItems = {
    _resources.getString(GL_CAT_CORPORATE),
    _resources.getString(GL_CAT_IT),
    _resources.getString(GL_CAT_RD),
    _resources.getString(GL_CAT_BBSM),
    _resources.getString(GL_CAT_MFG)
};

net.rim.device.api.system.TrackwheelListener.trackwheelClick()

Description:

Invoked when the trackwheel is clicked

Syntax:

public boolean trackwheelClick(int status, int time)

Parameters:

Modifier key status
Ticks since device reset

Returns:

True if the event was consumed; otherwise, false

Example:

public boolean trackwheelClick( int status, int time ) {
    Menu menu = new Menu();
    makeMenu( menu );
    menu.show();
    return true;
}

net.rim.device.api.system.TrackwheelListener.trackwheelUnclick()

Description:

Invoked when the trackwheel is released

Syntax:

public boolean trackwheelUnclick(int status, int time)

Parameters:

Modifier key status
Ticks since device reset

Returns:

True if the event was consumed; otherwise, false

Example:

public boolean trackwheelUnclick( int status, int time ) {
    return false;
}

net.rim.device.api.system.TrackwheelListener.trackwheelRoll()

Description:

Invoked when the trackwheel is rolled

Syntax:

public boolean trackwheelRoll(int amount, int status, int time)

Parameters:

Amount trackwheel has rotated since last event Negative values indicate an upwards (or backwards) roll Positive values indicate a downwards (or forwards) roll
Modifier key status
Ticks since device reset

Returns:

True if the event was consumed; otherwise, false

Example:

public boolean trackwheelRoll(int amount,int status,int time) {
    return false;
}

net.rim.device.api.ui.UiApplication.enterEventDispatcher()

Description:

Enters the event dispatcher
The thread that calls this method (typically main application thread) becomes the event-dispatching thread, which will execute all drawing and event-handling code
Under normal circumstances this method does not return
Method inherited from class net.rim.device.api.system.Application

Syntax:

public void enterEventDispatcher()

Parameter:

void

Returns:

void

Example:

class ExpenseReporterMain extends UiApplication {
    // main create a new instance of
    // the main app and add it to the
    // event dispatcher
    public static void main(String args[])
    {
        ExpenseReporterMain app = new ExpenseReporterMain();
        app.enterEventDispatcher();
    }

net.rim.device.api.ui.UiApplication.getActiveScreen()

Description:

Retrieve the topmost screen on the display stack (the currently active screen)
Specified by getActiveScreen in interface UiEngine

Syntax:

public final Screen getActiveScreen()

Parameter:

void

Returns:

Active screen, or null if the display stack has no screens

Example:

if (RMSAccessor.save(b, ExpenseReporterUtil.DBNAME)) {
    UiApplication uiApp = UiApplication.getUiApplication();
    uiApp.popScreen(uiApp.getActiveScreen());
    uiApp.popScreen(uiApp.getActiveScreen());
    System.exit(0);
}

net.rim.device.api.ui.UiApplication.getUiApplication()

Description:

Retrieves this UI application object

Syntax:

public static final UiApplication getUiApplication()

Parameter:

void

Returns:

This UI application

Example:

static {
    //Resources for the project
    _resources = ResourceBundle.getBundle(BUNDLE_ID, BUNDLE_NAME);

    // Close Menu Item
    _closeMenuItem = new MenuItem( _resources, MENUITEM_BACK, 200000,10 ) {
        public void run() {
            UiApplication uiApp = UiApplication.getUiApplication();
            UiApplication.getUiApplication().PopScreen(uiApp.getActiveScreen());
        }
    };
}

net.rim.device.api.ui.UiApplication.invokeLater()

Description:

Put runnable object into this application's event queue
Invoke this method, passing a runnable object, to have that object's run() method invoked on the dispatch thread, after all pending events are processed
Method inherited from class net.rim.device.api.system.Application

Syntax:

public final void invokeLater(Runnable runnable)

Parameter:

Runnable object to be placed on the dispatch thread's queue of events to execute

Returns:

void

Example:

Transport conn = new Transport();
conn.start();
synchronized(this) {
    _results = conn.getCodes(_superCode);

    if (_results != null && _results.getAt(0) != null) {
        updateList(_results.size());
    } else {
        updateList(0);
        UiApplication.getUiApplication().invokeLater(new Runnable() {
            public void run() {
                Dialog.alert(_resources.getString(ERROR_CONNECTION));
            }
        });
    }
}

net.rim.device.api.ui.UiApplication.popScreen()

Description:

Removes screen from display stack then updates screen
Specified by popScreen in interface UiEngine

Syntax:

public final void popScreen(Screen screen)

Parameter:

Screen to remove

Returns:

void

Throws:

IllegalArgumentException if screen not on stack

Example:

if (RMSAccessor.save(b, ExpenseReporterUtil.DBNAME)) {
    UiApplication uiApp = UiApplication.getUiApplication();
    uiApp.popScreen(uiApp.getActiveScreen());
    uiApp.popScreen(uiApp.getActiveScreen());
    System.exit(0);
}

net.rim.device.api.ui.UiApplication.pushScreen()

Description:

Pushes screen onto the display stack then paints it
Method is non-blocking and returns immediately
Will cause a layout and paint so add all screen controls before pushing it
Specified by pushScreen in interface UiEngine

Syntax:

public final void pushScreen(Screen screen)

Parameter:

Screen to push

Returns:

void

Example:

new MenuItem( _resources, MENUITEM_EXPENSE_GET_CC, 100, 100 ) {
    public void run() {
        if (_new) {
            saveSettings();
        }

        CodeGrabberScreen cgs = new CodeGrabberScreen(_ccCode);
        UiApplication.getUiApplication().pushScreen(cgs);
        setDirty(true);
    }
};

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BlackBerry and J2ME methods.inDepth();

Richard Evers, Editor

javax.microedition.io.Connector.open()

Description:

Syntax:

Parameter:

Returns:

Throws:

Example:

net.rim.device.api.ui.component.DateField()

Description:

Syntax:

Parameters:

Returns:

Example:

net.rim.device.api.ui.component.DateField.getDate()

Description:

Syntax:

Parameter:

Returns:

Example:

net.rim.device.api.ui.component.DateField.setEditable()

Description:

Syntax:

Parameter:

Returns:

Example:

net.rim.device.api.ui.component.Dialog.alert()

Description:

Syntax:

Parameter:

Returns:

Example:

net.rim.device.api.ui.component.Dialog.ask()

Description:

Syntax:

Parameter:

Returns:

Example:

net.rim.device.api.ui.component.EditField()

Description:

Syntax:

Parameters:

Returns:

Example:

net.rim.device.api.ui.component.EditField.setEditable()

Description:

Syntax:

Parameter:

Returns:

Example:

net.rim.device.api.ui.component.EditField.setFilter()

Description:

Syntax:

Parameter:

Returns:

Example:

net.rim.device.api.ui.Graphics.drawText()

Description:

Syntax:

Parameters:

Returns:

Example:

net.rim.device.api.ui.Graphics.drawPoint()

Description:

Syntax:

Parameters:

Returns:

Example:

net.rim.device.api.ui.Graphics.SetColor()

Description:

Syntax:

Parameter:

Returns:

Example: