CODEWITHSUNDEEP
javaimageswingjframe
anthonygore
anthonygore

Reputation: 4967

Coding a java game - JFrame not working as expected

I'd like some help in locating the error I'm making here. I'm relatively new to using Swing and this is the first game I've tried to make.

The problem is as follows: the code compiles fine, but when I run this code, nothing displays in the frame. I've noticed that if I remove the call to grabFrame in the Player class, and uncomment g.drawRect(...), that a rectangle will display in the frame, but when I add the grabFrame call back in, again nothing displays.

GamePanel:

import java.awt.Dimension;
import javax.swing.JFrame;

public class GamePanel extends JFrame {

    final static int GWIDTH = 512;
    final static int GHEIGHT = 512;
    static final Dimension screenSize = new Dimension(GWIDTH, GHEIGHT);
    JavaGame game;

    public GamePanel () {
        this.setTitle("Game");
        this.setSize(screenSize);
        this.setResizable(false);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        game = new JavaGame(screenSize);
        add(game);
    }

    public static void main (String[] args) {   
        GamePanel gp = new GamePanel();
    }
}

JavaGame:

import java.awt.Dimension;
    import java.awt.Graphics;    
    import javax.swing.JPanel;

    class JavaGame extends JPanel {

        // Game variables
        private GameEngine gameEngine;

        public JavaGame(Dimension screenSize) {
            this.setPreferredSize(screenSize);
            gameEngine = new GameEngine();
        }

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            gameEngine.draw(g);
        }
    }

GameEngine:

import java.awt.Graphics;

public class GameEngine {

    Player p1;
    public GameEngine () {
        p1 = new Player();
    }

    public void draw(Graphics g) {
        drawCharacters(g);
    }

    private void drawCharacters(Graphics g) {
            p1.draw(g);
    }
}

Player:

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;

public class Player {

    private BufferedImage frame;
    private URL frameURL;

    public Player() {
        try {
            frameURL = new File("C:/Users/admin/workspace/JavaGame/src/civ_walk_south.png").toURI().toURL();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        grabFrame();

    }

    private void grabFrame() {
            try {
             frame = ImageIO.read(frameURL);

        } catch (IOException e) {
            e.printStackTrace();
        }   
    }

    public void draw(Graphics g) {          
        g.drawImage(frame, 50, 50, null);
        //g.drawRect(50, 50, 50, 50); // put this here for testing, when uncommented it only works if call to grabFrame() is removed from constructor
    }

}

Upvotes: 1

Views: 822

Answers (2)

NGSoftware
NGSoftware

Reputation: 27

put add(game) at the topit might also help to setVisible(true) at the very end as well. You also want to call a pack method as well

In the java game class don't declare this.setPreferredSize(screensize) in the java game class instead put it in game panel class also don't just call setPreferredSize() you alos want setMaximumSize() and setMinimumSize() so your game panel class should look like this.

import java.awt.Dimension;
import javax.swing.JFrame;

public class GamePanel extends JFrame {

final static int GWIDTH = 512;
final static int GHEIGHT = 512;
static final Dimension screenSize = new Dimension(GWIDTH, GHEIGHT);
JavaGame game;

public GamePanel () {
    game = new JavaGame(screenSize); 

    game.setPreferredSize(screenSize);
    game.setMaximumSize(screenSize);
    game.setMinimumSize(screenSize);       

    add(game);
    this.setTitle("Game");
    this.setSize(screenSize);
    this.setResizable(false);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setVisible(true);

}

public static void main (String[] args) {   
    GamePanel gp = new GamePanel();
}
}

Hope this helps.

Upvotes: 0

Hovercraft Full Of Eels
Hovercraft Full Of Eels

Reputation: 285401

Regarding:

public GamePanel () {
    this.setTitle("Game");
    this.setSize(screenSize);
    this.setResizable(false);
    this.setVisible(true);  // *****
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    game = new Game(screenSize);
    add(game);
}

Call setVisible(true) on your JFrame after adding all components, not before.

So,....

public GamePanel () {
    this.setTitle("Game");
    //  this.setSize(screenSize);  // **** don't set sizes like this
    this.setResizable(false);
    // this.setVisible(true);  // *****
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    game = new Game(screenSize);
    add(game);
    pack();  // **** this should size the GUI to the preferred sizes
    setVisible(true); // **** call this here ****
}

Also, have you tested to see if the image obtained is null or not before drawing it?

This smells funny to me as your image path appears to be in a location that will be included inside of the jar file:

frameURL = new File("C:/Users/admin/workspace/JavaGame/src/civ_walk_south.png")
              .toURI().toURL();

Why not get your image as a resource and not first as a file?

Upvotes: 1

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