Pointer Example

This type of example is basically used in touch screen technology, here we are trying to create a pointer which location is based on the screen touch pointer. The source code for this small example of touch screen application.


public void pressPointer (int x, int y) {

    action = "Pointer Pressed";

    this.x = x;

    this.y = y;

    repaint ();

  }

is used to initialize the pointer location when pressed. The source code

public void releasePointer (int x, int y) {

    action = "Pointer Released";

    this.x = x;

    this.y = y;

    repaint ();

  }

is used to released the pointer from his location. And the source code

public void dragPointer (int x, int y) {

    action = "Pointer Repeated";

    this.x = x;

    this.y = y;

    repaint ();

  }

is used when repeating the pointer, then it relocate the location of the pointer. The Application is as follows:

Source Code of PointerExample.java


import javax.microedition.midlet.*;

import javax.microedition.lcdui.*;



public class PointerExample extends MIDlet{

  private Display display;



  public void startApp(){

    display = Display.getDisplay(this);

    display.setCurrent (new PointerCanvas()); 

  }



  public void pauseApp(){}



  public void destroyApp (boolean forced){}

}



class PointerCanvas extends Canvas {

  String action = "Press Pointer!";

  int x;

  int y;



  public void pressPointer (int x, int y) {

    action = "Pointer Pressed";

    this.x = x;

    this.y = y;

    repaint ();

  }



  public void releasePointer (int x, int y) {

    action = "Pointer Released";

    this.x = x;

    this.y = y;

    repaint ();

  }

  

  public void dragPointer (int x, int y) {

    action = "Pointer Repeated";

    this.x = x;

    this.y = y;

    repaint ();

  }



  public void paint (Graphics g) {

    g.setGrayScale (255);

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

    g.setGrayScale (0);

    g.drawString (action + " " + x + "/" + y, 0, 0, 

    Graphics.TOP|Graphics.LEFT);

    g.drawLine (x-4, y, x+4, y);

    g.drawLine (x, y-4, x, y+4);

  }

}

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