How can I use abstract method in J2ME?

Question

I implemented some code that has an alert class which is type of Canvas, and it has a keyPress method which must work different for each class that using alert class. For example the keyPress method has 2 buttons that the function of each button is different for each class! Could anyone tell me How can I implement that ?

public class myAlert extends Canvas implements CommandListener{

public myAlert(Midlet midlet,int width,int height,String str,String left_str,String right_str){ } protected void paint(Graphics g) { g.setColor(0, 0,0); g.drawRoundRect(5, 180, width-10, height, 8, 8); g.drawRoundRect(15, 185, width-15, height-5, 7, 7); g.setColor(0xbfd4f6); g.fillRoundRect(0, 180, width, height, 8, 8); /////////////// } protected void keyPressed(int keyCode) { switch(keyCode){ case -6: // select button
// break; case -7: //close button

        break;
}

} } Public class M(){
protected void keyPressed(int keyCode) {

    switch (state) {
 case STATE_INPUT_LEFT:
      // do work for focus on the left
      if (keyCode >= KEY_NUM0 && keyCode <= KEY_NUM9 && digitsEntered < 10) {
        digits_left[digitsEntered] = (char) ('0' + (keyCode - KEY_NUM0));
        digitsEntered++;
        repaint();
        if(digitsEntered>=8){
         state=STATE_INPUT_RIGHT;
            m= new myAlert(midlet,w, 150,"Ok " ,"exit",”system”);

//I want that if user click on Ok button the main page must be shown to user Display.getDisplay(midlet).setCurrent( m); break; } } } Public class N(){ public void commandAction(Command c, Displayable d) { String label = c.getLabel(); if(label.equals("Exit")){ midlet.exit(); } else if(label.equals("Enter")){ m= new myAlert(midlet,w, 150,”yes”,”No”,”Print” ); // I want here that if user clicks on ok another message be shown to user Display.getDisplay(midlet).setCurrent( m);

}
}

here is part of my code! as you see in M class and N class function of left button of Alert class is diffrent from each other! Now Could you help me?

Answer 1

In the parent, have the handler detect the specific button and delegate to two separate abstract methods. In the child, implement the methods.