Question

I have created a class that extends JLabel to use as my object moving around a JPanel for a game.

import javax.swing.*;

public class Head extends JLabel {

 int xpos;
 int ypos;

 int xvel;
 int yvel;

 ImageIcon chickie = new ImageIcon(
        "C:\\Users\\jjpotter.MSDOM1\\Pictures\\clavalle.jpg");
 JLabel myLabel = new JLabel(chickie);

 public Head(int xpos, int ypos, int xvel, int yvel){

  this.xpos = xpos;
  this.ypos = ypos;
  this.xvel = xvel;
  this.yvel = yvel;
 }

 public void draw(){
  myLabel.setLocation(xpos, ypos);
 }

 public double getXpos() {
  return xpos;
 }

 public double getYpos() {
  return ypos;
 }

 public int getXvel() {
  return xvel;
 }

 public int getYvel() {
  return yvel;
 }

 public void setPos(int x, int y){

  xpos = x;
  ypos = y;

 }

}

I am then trying to add it onto my JPanel. From here I will randomly have it increment its x and y coordinates to float it around the screen. I can not get it to paint itself onto the JPanel. I know there is a key concept I am missing here that involves painting components on different panels. Here is what I have in my GamePanel class

import java.awt.Dimension;
import java.util.Random;
import javax.swing.*;


public class GamePanel extends JPanel {

 Random myRand = new Random();
 Head head = new Head(20,20,0,0);

 public GamePanel(){

  this.setSize(new Dimension(640, 480));
  this.add(head);

 }

}

Any suggestions on how to get this to add to the JPanel? Also, is this a good way to go about having the picture float around the screen randomly for a game?

Answer 1

First of all there is no need to extend a JLabel to do this.

a) you set the size of the label after you add the image to the label by using:

label.setSize( label.getPreferredSize() );

b) You don’t need the draw(), and all the setter methods. To move the label all you do is use:

label.setLocation(...);

c) if you want to increment the location you would use something like:

label.setLocation( label.getLocation().x + 5, …);

Once you set the size and location of the label you can add it directly to the panel. Make sure you have done:

panel.setPreferredSize() 

when you add your panel to the content pane of your frame.

Your code is too vague to give specific suggestions. If you need more help post your SSCCE. Your problem could be the usage of layout manager or the fact you aren’t using layout managers.