J2ME : How to save a line created by using drawline() and start again from the line's end point keeping the previous one?

Question

I am trying to create a midlet with which I can draw anything using my cursor keys. I have used drawLine method. But I want to create a line then change direction keeping the previous line but the line keeps rotating.

Basically I should be able to draw anything in any direction.

This is my code:

public class Pacer extends MIDlet{
public void startApp() {
Displayable d = new PacerCanvas();

d.addCommand(new Command("Exit", Command.EXIT, 0));
d.setCommandListener(new CommandListener() {
  public void commandAction(Command c, Displayable s) {
    notifyDestroyed();
  }
} );

Display.getDisplay(this).setCurrent(d);
 }

public void pauseApp() { }

public void destroyApp(boolean unconditional) { }
}
/**
*
* @author Rumman
*/
import javax.microedition.lcdui.*;

public class PacerCanvas extends Canvas {

private String name;
private int w,h,x1,y1,x2,y2;

public PacerCanvas(){
w = getWidth();
h = getHeight();
x1 =  w/2 ;
y1 = h/2 ;
x2 = x1 ;
y2 = y1 ;
}

protected void keyPressed(int key){
    name = getKeyName(key);
    if(name.equals("Right") || name.equals("6")){
    x2++;
    }
    else if(name.equals("Left") || name.equals("4")){
    x2--;
    }
    else if(name.equals("Up") || name.equals("2")){
    y2--;
    }
    else if(name.equals("Down") || name.equals("8")){
    y2++;
    }
    else if(name.equals("1")){
        x2--;
        y2++;
    }
    else if(name.equals("3")){
        x2++;
        y2++;
    }
    else if(name.equals("7")){

    }
    else if(name.equals("9")){
    }
    repaint();  
}

public void paint(Graphics g) {

g.setColor(0xffffff);
g.fillRect(0, 0, w, h);

g.setColor(0x000000);
g.drawLine(x1, y1, x2, y2);
}
}

Answer 1

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

/**
*
* @author Rumman
*/
import javax.microedition.lcdui.*;

public class PacerCanvas extends Canvas {

private String name;
private int w,h,x1,y1,x2,y2;
private Image image;
private Graphics ig;
public PacerCanvas(){
w = getWidth();
h = getHeight();
x1 =  w/2 ;
y1 = h/2 ;
x2 = x1 ;
y2 = y1 ;
image = Image.createImage(w,h);

ig = image.getGraphics();

ig.setColor(255, 255, 255);
ig.fillRect(0, 0, w, h);

}
protected void keyRepeated(int key){
keyPressed(key);
keyPressed(key);// I used this method multiple times as it makes it faster 
keyPressed(key);
keyPressed(key);
keyPressed(key);
keyPressed(key);
keyPressed(key);
keyPressed(key);
}
protected void keyPressed(int key){
    name = getKeyName(key);
    if(name.equals("Right") || name.equals("6")){
    x2++;
    }
    else if(name.equals("Left") || name.equals("4")){
    x2--;
    }
    else if(name.equals("Up") || name.equals("2")){
    y2--;
    }
    else if(name.equals("Down") || name.equals("8")){
    y2++;
    }
    else if(name.equals("1")){
        x2--;
        y2--;
    }
    else if(name.equals("3")){
        x2++;
        y2--;
    }
    else if(name.equals("7")){
        x2--;
        y2++;
    }
    else if(name.equals("9")){
        x2++;
        y2++;
    }
    repaint();  
}

public void paint(Graphics g) {


ig.setColor(0x000000);
ig.drawLine(x1, y1, x2, y2);
g.drawImage(image, 0, 0, Graphics.TOP|Graphics.LEFT);
x1=x2;
y1=y2;


}

public void draw(Image i) {
Graphics ig = i.getGraphics();
Pacer p = new Pacer();
// p.Display.getDisplay(this).setCurrent(i);
}
}