Java - ayuda cdel MIDlet

el problema que tengo es que tengo es que al ejecutar la aplicacion para el movil no me muestra el mapa "pantalla". pantalla contiene un papa de un juego y un sprite llamado miSprite. el programa no da errores.

import java.io.IOException;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
* @author Aitor
*/
public class juego extends MIDlet implements CommandListener {

private boolean midletPaused = false;
//<editor-fold defaultstate="collapsed" desc=" Generated Fields ">
private Command exitCommand;
private Form form;
private StringItem stringItem;
//</editor-fold>
private SSCanvas pantalla;

public juego() {
}



private void initialize() {

}

public void resumeMIDlet() {

}

public void switchDisplayable(Alert alert, Displayable nextDisplayable) {

Display display = getDisplay();
if (alert == null) {
display.setCurrent(nextDisplayable);
} else {
display.setCurrent(alert, nextDisplayable);
}

}

public void commandAction(Command command, Displayable displayable) {

if (displayable == form) {
if (command == exitCommand) {

exitMIDlet();

}
}

}

public Command getExitCommand() {
if (exitCommand == null) {
exitCommand = new Command("Exit", Command.EXIT, 0);
}
return exitCommand;
}

public Form getForm() {
if (form == null) {
// write pre-init user code here
form = new Form("Welcome", new Item[] { getStringItem() });
form.addCommand(getExitCommand());
form.setCommandListener(this);
// write post-init user code here
}
return form;
}

public StringItem getStringItem() {
if (stringItem == null) {

stringItem = new StringItem("Hello", "Hello, World!");

}
return stringItem;
}

public Display getDisplay() {
return Display.getDisplay(this);
}

public void exitMIDlet() {
switchDisplayable(null, null);
destroyApp(true);
notifyDestroyed();
}

public void startApp() {
if (midletPaused) {
resumeMIDlet();
} else {
initialize();

pantalla = new SSCanvas();

new Thread(pantalla).start();
Display d = this.getDisplay();

}
midletPaused = false;
}

public void pauseApp() {
midletPaused = true;
}

public void destroyApp(boolean unconditional) {
}

class SSCanvas extends Canvas implements Runnable {

private Sprite miSprite = new Sprite(1);
private Sprite [] tile=new Sprite[5];
private int sleepTime, indice_in,indice, xTiles,yTiles;
private int deltaX;
private int deltaY;
private int map[]={ 1,1,1,1,1,1,1,
1,1,1,1,1,1,1,
1,2,1,1,1,1,1,
1,1,1,4,1,1,1,
1,1,1,1,1,1,1,
1,1,3,1,2,1,1,
1,1,1,1,1,1,1,
1,4,1,1,1,1,1,
1,1,1,1,3,1,1,
1,1,1,1,1,1,1,
1,4,1,1,1,1,1,
1,1,1,3,1,1,1,
1,1,1,1,1,1,1,
1,1,1,1,1,1,1,
1,2,1,1,1,1,1,
1,1,1,4,1,1,1,
1,1,1,1,1,1,1,
1,1,3,1,2,1,1,
1,1,1,1,1,1,1,
1,4,1,1,1,1,1};

public SSCanvas() {

this.miSprite.addFrame(1, "imagenes/avion.png");

this.miSprite.on();

}

public void paint(Graphics g) {

int x=0, y=0, t=0;
int i, j;

g.setColor(255, 255, 255);
g.fillRect(0, 0, getWidth(), getHeight());

for(i=0;i<yTiles;i++){
for(j=0;j<xTiles;j++){

t=map[this.indice+(i*xTiles+j)];
x=j*32;
y=(i-1)*32+this.indice_in;

this.tile[t].setX(x);
this.tile[t].setY(y);
this.tile[t].draw(g);

}
}
this.miSprite.setX(miSprite.getX());
this.miSprite.setY(miSprite.getY());
this.miSprite.draw(g);
}

public void keyReleased(int keyCode) {

int action = getGameAction(keyCode);

switch (action) {

case LEFT:
this.deltaX = 0;
break;

case RIGHT:
this.deltaX = 0;
break;

case UP:
this.deltaY = 0;
break;

case DOWN:
this.deltaY = 0;
break;

}

}

public void keyPressed(int keyCode) {

int action = getGameAction(keyCode);

switch (action) {

case LEFT:
this.deltaX = -5;
break;

case RIGHT:
this.deltaX = 5;
break;

case UP:
this.deltaX = -5;
break;

case DOWN:
this.deltaX = 5;
break;
}
}

public void run() {

iniciar();

while (true) {
doScroll();
computePlayer();
repaint();
serviceRepaints();

try {
Thread.sleep(sleepTime);
} catch (InterruptedException ex) {
ex.printStackTrace();
}

}
}

private void iniciar() {

int i;

this.sleepTime=50;
this.miSprite.setX(this.getWidth()/2);
this.miSprite.setY(this.getHeight()-20);
this.deltaX=0;
this.deltaY=0;
this.xTiles=7;
this.yTiles=8;
this.indice=this.map.length-(xTiles*yTiles);
this.indice_in=0;

//iniciamos los tiles
for(i=1;i<=4;i++){
this.tile[i]=new Sprite(1);
this.tile[i].on();

}
this.tile[1].addFrame(1, "imagenes/image32.png");
this.tile[2].addFrame(1, "imagenes/image33.png");
this.tile[3].addFrame(1, "imagenes/image34.png");
this.tile[4].addFrame(1, "imagenes/image33.png");


}

private void computePlayer() {

if (miSprite.getX() + deltaX > 0 && miSprite.getX() + deltaX < getWidth() && miSprite.getY() + deltaY > 0 && miSprite.getY() + deltaY < getHeight()) {

miSprite.setX(miSprite.getX() + deltaX);
miSprite.setY(miSprite.getY() + deltaY);

}
}

private void doScroll() {

this.indice_in+=2;
if(this.indice_in>=32){
this.indice_in=0;
this.indice-=xTiles;
}

if(this.indice<=0){

//si llegamos al final, empezamos de nuevo
this.indice=this.map.length-(xTiles*yTiles);
this.indice_in=0;
}
}
}
}