Sprite não aparece!

import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
 
public class ExampleGameCanvas extends GameCanvas implements Runnable {
   
   private boolean isPlay; // Game Loop runs when isPlay is true
   private long delay; // To give thread consistency 
   private int currentX, currentY; // To hold current position of the 'X'
   private int width; // To hold screen width 
   private int height; // To hold screen height
   // Sprites to be used.
   private Sprite nonTransparentSprite;
   
   // Constructor and initialization
   public ExampleGameCanvas() throws Exception {
      super(true);
      width = getWidth();
      height = getHeight();
      currentX = width / 2;
      currentY = height / 2;
      delay = 20;
      // Load image to sprite.
      Image imagem = Image.createImage("sprite.png");
      nonTransparentSprite = new Sprite(imagem, 32, 32);
   }
 
   // Automatically start thread for game loop
 
   public void start() {
      isPlay = true;
      Thread t = new Thread(this);
      t.start();
   }
   
   public void stop() { isPlay = false; }
      // Main Game Loop
   
   public void run() {
      Graphics g = getGraphics();
      while (isPlay == true) {
         input();
         drawScreen(g);
         try { 
            Thread.sleep(delay); 
         }
         catch (InterruptedException ie) {
         }
   }
 
}
   // Method to Handle User Inputs
   private void input() {
 
   int keyStates = getKeyStates();
   nonTransparentSprite.setFrame(0);
        
   // Left
   if ((keyStates & LEFT_PRESSED) != 0) {
      currentX = Math.max(0, currentX - 1);
      nonTransparentSprite.setFrame(1);
   }
   // Right
   if ((keyStates & RIGHT_PRESSED) !=0 ) 
      if ( currentX + 5 < width) {
         currentX = Math.min(width, currentX + 1);
         nonTransparentSprite.setFrame(3);
      }
   // Up
   if ((keyStates & UP_PRESSED) != 0) {
      currentY = Math.max(0, currentY - 1);
      nonTransparentSprite.setFrame(2);
   }
   // Down
   if ((keyStates & DOWN_PRESSED) !=0)
      if ( currentY + 10 < height) {
         currentY = Math.min(height, currentY + 1);
         nonTransparentSprite.setFrame(4);
      }
}
 
   // Method to Display Graphics
   private void drawScreen(Graphics g) {
      g.setColor(0xffffff);
      g.fillRect(0, 0, getWidth(), getHeight());
      g.setColor(0x0000ff);
      // Display sprites.
      nonTransparentSprite.setPosition(currentX, currentY);
      nonTransparentSprite.paint(g);
      flushGraphics();
   }
 
}

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
 
public class ExampleGameCanvasMidlet extends MIDlet {
 
   private Display display;
  
   public void startApp() {
      try {
         display = Display.getDisplay(this); 
         ExampleGameCanvas gameCanvas = new ExampleGameCanvas();
         gameCanvas.start();
         display.setCurrent(gameCanvas);
      }
      catch(Exception e) {
         System.out.println(e);
      }
   }
 
   public Display getDisplay() {
      return display;
   }
   
   public void pauseApp() {
   }
 
   public void destroyApp(boolean unconditional) {
      exit();
   }
 
   public void exit() {
      System.gc();
      destroyApp(false);
      notifyDestroyed();
   }
 
}