Writing Custom TextBox in Blackberry

Something it is required to write customized TextBox because using native API you cannot get the border, backgound color, backgroung image, left shift characters when text are more than one line without customizing.

In such type of cases you can create a Class extending Field
and the following things have to override:
* sublayout()
* paint()
* getPreferredWidth()
* getPreferredHeight()

The below Class demonstrate the above implementation:

import net.rim.device.api.ui.Manager; import net.rim.device.api.ui.Field; import net.rim.device.api.ui.component.EditField; import net.rim.device.api.ui.component.BasicEditField; import net.rim.device.api.system.EncodedImage; import net.rim.device.api.system.Bitmap; import net.rim.device.api.system.Display; import net.rim.device.api.ui.Graphics; import net.rim.device.api.system.Characters; import net.rim.device.api.math.Fixed32; import net.rim.device.api.ui.DrawStyle; import net.rim.device.api.ui.Font; public class CustomTextBox extends Manager { /** * Default margins */ private final static int DEFAULT_LEFT_MARGIN = 10; private final static int DEFAULT_RIGHT_MARGIN = 10; private final static int DEFAULT_TOP_MARGIN = 5; private final static int DEFAULT_BOTTOM_MARGIN = 5; /** * Default paddings */ private final static int DEFAULT_LEFT_PADDING = 10; private final static int DEFAULT_RIGHT_PADDING = 10; private final static int DEFAULT_TOP_PADDING = 5; private final static int DEFAULT_BOTTOM_PADDING = 5; /** * Margins around the text box */ private int topMargin = DEFAULT_TOP_MARGIN; private int bottomMargin = DEFAULT_BOTTOM_MARGIN; private int leftMargin = DEFAULT_LEFT_MARGIN; private int rightMargin = DEFAULT_RIGHT_MARGIN; /** * Padding around the text box */ private int topPadding = DEFAULT_TOP_PADDING; private int bottomPadding = DEFAULT_BOTTOM_PADDING; private int leftPadding = DEFAULT_LEFT_PADDING; private int rightPadding = DEFAULT_RIGHT_PADDING; /** * Amount of empty space horizontally around the text box */ private int totalHorizontalEmptySpace = leftMargin + leftPadding + rightPadding + rightMargin; /** * Amount of empty space vertically around the text box */ private int totalVerticalEmptySpace = topMargin + topPadding + bottomPadding + bottomMargin; /** * Minimum height of the text box required to display the text entered */ private int minHeight = getFont().getHeight() + totalVerticalEmptySpace; /** * Width of the text box */ private int width = Display.getWidth(); /** * Height of the text box */ private int height = minHeight; /** * Background image for the text box */ private EncodedImage backgroundImage; /** * Bitmap version of the backgroundImage. * Needed to reduce the calculation overhead incurred by * scaling of the given image * and derivation of Bitmap from the * EncodedImage every time it is needed. */ private Bitmap bitmapBackgroundImage; /** * The core element of this text box */ private EditField editField; //private BasicEditField editField; //private String entireText; public CustomTextBox() { // Let the super class initialize the core super(0); // An edit field is the sole field of this manager. editField = new EditField(); //editField = new CustomEditField(); add(editField); } public CustomTextBox(EncodedImage backgroundImage) { this(); setBackgroundImage(backgroundImage); } public void setSize(int width, int height) { boolean isChanged = false; if (width > 0 // Ignore invalid width && this.width != width) { this.width = width; isChanged = true; } // Ignore the specified height if it is less // than the minimum height required to display the text. if (height > minHeight && height != this.height) { this.height = height; isChanged = true; } // If width/height has been changed and background image // is available, adapt it to the new dimension if (isChanged == true && backgroundImage != null) { bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, this.width - (leftMargin+rightMargin), this.height - (topMargin+bottomMargin)); } } public void setWidth(int width) { if (width > 0 && width != this.width) { this.width = width; // If background image is available, adapt it to the new width if (backgroundImage != null) { bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, this.width - (leftMargin+rightMargin), this.height - (topMargin+bottomMargin)); } } } public void setHeight(int height) { // Ignore the specified height if it is // less than the minimum height required to display the text. if (height > minHeight) { this.height = height; // If background image is available, adapt it to the new width if (backgroundImage != null) { bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, this.width - (leftMargin+rightMargin), this.height - (topMargin+bottomMargin)); } } } public void setBackgroundImage(EncodedImage backgroundImage) { this.backgroundImage = backgroundImage; // Consider the height of background image in // calculating the height of the text box. // setHeight() does not ensure that specified // height will be in effect, of course, for valid reasons. // So derivation of Bitmap image in the setHeight() method is not sure. setHeight(backgroundImage.getHeight() + topMargin + bottomMargin); if (bitmapBackgroundImage == null) { bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, this.width - (leftMargin+rightMargin), this.height - (topMargin+bottomMargin)); } } /** * Generate and return a Bitmap Image scaled according * to the specified width and height. * * @param image EncodedImage object * @param width Intended width of the returned Bitmap object * @param height Intended height of the returned Bitmap object * @return Bitmap object */ private Bitmap getScaledBitmapImage(EncodedImage image, int width, int height) { // Handle null image if (image == null) { return null; } int currentWidthFixed32 = Fixed32.toFP(image.getWidth()); int currentHeightFixed32 = Fixed32.toFP(image.getHeight()); int requiredWidthFixed32 = Fixed32.toFP(width); int requiredHeightFixed32 = Fixed32.toFP(height); int scaleXFixed32 = Fixed32.div(currentWidthFixed32, requiredWidthFixed32); int scaleYFixed32 = Fixed32.div(currentHeightFixed32, requiredHeightFixed32); image = image.scaleImage32(scaleXFixed32, scaleYFixed32); return image.getBitmap(); } protected void sublayout(int width, int height) { // We have one and only child - the edit field. // Place it at the appropriate place. Field field = getField(0); layoutChild(field, this.width - totalHorizontalEmptySpace, this.height - totalVerticalEmptySpace); setPositionChild(field, leftMargin+leftPadding, topMargin+topPadding); setExtent(this.width, this.height); } public void setTopMargin(int topMargin) { this.topMargin = topMargin; } public void setBottomMargin(int bottomMargin) { this.bottomMargin = bottomMargin; } protected void paint(Graphics graphics) { // Draw background image if available, otherwise draw a rectangle if (bitmapBackgroundImage == null) { //graphics.drawRect(leftMargin, topMargin, width - (leftMargin+rightMargin), height - (topMargin+bottomMargin)); graphics.drawRoundRect(leftMargin, topMargin, width - (leftMargin+rightMargin), height - (topMargin+bottomMargin), 5, 5); } else { graphics.drawBitmap(leftMargin, topMargin, width - (leftMargin+rightMargin), height - (topMargin+bottomMargin), bitmapBackgroundImage, 0, 0); } // Determine the rightward text that can fit into the visible edit field EditField ef = (EditField)getField(0); String entireText = ef.getText(); boolean longText = false; String textToDraw = ""; Font font = getFont(); int availableWidth = width - totalHorizontalEmptySpace; if (font.getAdvance(entireText) <= availableWidth) { textToDraw = entireText; } else { int endIndex = entireText.length(); for (int beginIndex = 1; beginIndex < endIndex; beginIndex++) { textToDraw = entireText.substring(beginIndex); if (font.getAdvance(textToDraw) <= availableWidth) { longText = true; break; } } } if (longText == true) { // Force the edit field display only the truncated text ef.setText(textToDraw); // Now let the components draw themselves super.paint(graphics); // Return the text field its original text ef.setText(entireText); } else { super.paint(graphics); } } public int getPreferredWidth() { return width; } public int getPreferredHeight() { return height; } protected boolean keyChar(char ch, int status, int time) { if (ch == Characters.ENTER) { return true; } else { return super.keyChar(ch, status, time); } } public String getText() { return ((EditField)getField(0)).getText(); } public void setText(final String text) { ((EditField)getField(0)).setText(text); } }