BlackBerry Ticker like LabelField

in BlackBerry we can make a Ticker like field where the text is in a moving condition. it is some times very helpful to make some customization and to achieve interactive UI in BlackBerry. we just need to make a class file with name MovingLabelField.java and copy the given below code to it.


import java.util.Timer;
import java.util.TimerTask;

import net.rim.device.api.system.Display;
import net.rim.device.api.ui.DrawStyle;
import net.rim.device.api.ui.Font;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.component.LabelField;

public class MovingLabelField extends LabelField{
int currentChar = 0;
String currentText = null;
Font ourFont;
private Timer _scrollTimer;
private TimerTask _scrollTimerTask;

public MovingLabelField (String text){
super(text);

}
public void paint(Graphics graphics) {
currentText = this.getText();
if (currentChar < currentText.length()) {
currentText = currentText.substring(currentChar);
}
graphics.drawText(currentText, 0, 0, DrawStyle.ELLIPSIS,
Display.getWidth());
}
protected void paintBackground(net.rim.device.api.ui.Graphics g) {
g.setColor(0x666666);
}


protected void onDisplay() {
startScroll();
}

protected void onUnfocus() {
startScroll();
}

private void startScroll() {
// Start scrolling
final String fullText = this.getText();
if (_scrollTimer == null) {
_scrollTimer = new Timer();
_scrollTimerTask = new TimerTask() {
public void run() {
currentChar = currentChar + 4;
if (currentChar > fullText.length()) {
currentChar = 0;
}
invalidate();
}
};
_scrollTimer
.scheduleAtFixedRate(_scrollTimerTask, 500, 500);
}
}

protected void onFocus(int direction) {
if (_scrollTimer != null) {
_scrollTimerTask.cancel();
_scrollTimer.cancel();
_scrollTimer = null;
_scrollTimerTask = null;
}
}

protected boolean navigationMovement(int dx, int dy, int status,
int time) {
currentText = this.getText();
int oldCurrentChar = currentChar;
if (Math.abs(dx) > Math.abs(dy)) {
// horizontal scroll
if (dx > 0) {
currentChar = Math.min(currentText.length() - 1,
currentChar + 1);
} else if (dx < 0) {
currentChar = Math.max(0, currentChar - 1);
}
if (oldCurrentChar != currentChar) {
this.invalidate();
}
return true;
} else {
return super.navigationMovement(dx, dy, status, time);
}
}
}