CODEWITHSUNDEEP
javaswinggraphicsuser-inputkey-bindings
Neeek
Neeek

Reputation: 53

Java- Key Bindings not working / actionPerformed not being called

I finally learned how to get graphics to work in java thanks to the guy who helped me on my previous question, but now I can't get key bindings to work. I know that the graphics method is called as I need it to, and I think that I have declared my key bindings properly, but the 'actionPerformed()' method won't call. I tried using the singleton pattern to get my player object across classes and I feel that it somehow screwed everything else up. I tried looking through quite a few other questions relating to my issue but I still couldn't figure it out, unless I'm overloooking something obvious. I'd REALLY appreciate if one of you majestic programming wizards could crack this one:

import java.net.URL;

import javax.swing.ImageIcon;
import javax.swing.KeyStroke;

public class Player {
    private int xLoc, yLoc;
    private boolean isFiring;
    private String filename;
    private ImageIcon imageicon;
    private URL imgURL;

    private static Player player;

    public Player(int xl, int yl, boolean fire, String name){
        xLoc = xl;
        yLoc = yl;
        isFiring = fire;
        filename = name;
        imgURL = getClass().getResource(name);
        imageicon = new ImageIcon(imgURL);
    }

    public static Player getInstance(){
        if(player == null){
            player = new Player(0,0,false,"Dog.jpg");
        }
        return player;
    }

    public void fire(){

    }

    public int getX(){
        return xLoc;
    }
    public int getY(){
        return yLoc;
    }
    public void newX(int x){
        xLoc = x;
    }
    public ImageIcon getImg() {
        return imageicon;
    }
    public void newImg(ImageIcon ii){
        imageicon = ii;
    }
    public URL getURL(){
        return imgURL;
    }
    public void newURL(String n){
        imgURL = getClass().getResource(n);
    }
    public void updateObject(){
        imageicon = new ImageIcon(imgURL);
    }
}

.

import java.awt.Graphics;
import java.net.URL;

import javax.swing.JPanel;
import javax.swing.KeyStroke;

public class GamePanel extends JPanel{
    int nameSwap = 0;
    Player player;
    public GamePanel(){
        player = Player.getInstance();
        repaint();
        System.out.println("Repaint method called");

        this.getInputMap().put(KeyStroke.getKeyStroke("A"), "moveLeft");
        this.getActionMap().put("moveLeft", new MoveLR(-1));

        this.getInputMap().put(KeyStroke.getKeyStroke("D"), "moveRight");
        this.getActionMap().put("moveRight", new MoveLR(1));

        this.getInputMap().put(KeyStroke.getKeyStroke("S"), "fire");
        this.getActionMap().put("fire", new Fire());
    }
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        g.drawImage(player.getImg().getImage(), player.getX(), player.getY(), 50, 50, null);
        //System.out.println("Graphics method called");
    }
}

.

import java.awt.Color;

import javax.swing.JFrame;

public class Window {

    public Window() {
        JFrame frame = new JFrame("Epic Game");
        frame.setSize(800,600);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        GamePanel panel = new GamePanel();
        frame.add(panel);

        frame.setVisible(true);

        while(true){
            panel.repaint();
        }
    }

    public static void main(String[] args){
        Window window = new Window();
    }
}

.

import java.awt.event.ActionEvent;
import java.beans.PropertyChangeListener;

import javax.swing.Action;

public class MoveLR implements Action{
    private int moveVal;
    Player player;
    public MoveLR(int mv){
        moveVal = mv;
        player = Player.getInstance();
        System.out.println("New MoveLR object made");
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {
        // TODO Auto-generated method stub
        player.newX(player.getX() + 1);
        System.out.println("actionPerformed() called");
    }

    @Override
    public void addPropertyChangeListener(PropertyChangeListener arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public Object getValue(String arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public boolean isEnabled() {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public void putValue(String arg0, Object arg1) {
        // TODO Auto-generated method stub

    }

    @Override
    public void removePropertyChangeListener(PropertyChangeListener arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void setEnabled(boolean arg0) {
        // TODO Auto-generated method stub

    }
}

Upvotes: 3

Views: 514

Answers (1)

Hovercraft Full Of Eels
Hovercraft Full Of Eels

Reputation: 285405

You're using the wrong InputMap. Use the getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW). This way you'll bind to keys that are active when the JPanel doesn't have focus but is displayed in a window that does. The default InputMap is the one used for JComponent.WHEN_FOCUSED which is only valid when the bound component has focus, which is not what you want to do or use.

this.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke("A"), 
        "moveLeft");

Also use classes that extend AbstractAction, not ones that implement Action as your Actions are not fully wired. And yes, you can repaint at the end of the actionPerformed as long as you have a reference to the JPanel, which the ActionEvent can get you.

Test program:

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;

import javax.swing.AbstractAction;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;

public class Window {

   public Window() {
      JFrame frame = new JFrame("Epic Game");
      frame.setSize(800, 600);
      frame.setLocationRelativeTo(null);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      GamePanel panel = new GamePanel();
      frame.add(panel);

      frame.setVisible(true);

      // !! while (true) {
      // panel.repaint();
      // }
   }

   public static void main(String[] args) {
      new Window();
   }
}

@SuppressWarnings("serial")
class GamePanel extends JPanel {
   int nameSwap = 0;
   Player player;

   public GamePanel() {
      player = Player.getInstance();
      repaint();
      System.out.println("Repaint method called");

      this.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke("A"), "moveLeft");
      this.getActionMap().put("moveLeft", new MoveLR(-1));

      this.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke("D"), "moveRight");
      this.getActionMap().put("moveRight", new MoveLR(1));

      this.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke("S"), "fire");
      this.getActionMap().put("fire", new Fire());
   }

   public void paintComponent(Graphics g) {
      super.paintComponent(g);
      g.drawImage(player.getImg().getImage(), player.getX(), player.getY(), 50,
            50, null);
      // System.out.println("Graphics method called");
   }
}

class Player {
   private int xLoc, yLoc;
   private boolean isFiring;
   private String filename;
   private ImageIcon imageicon;
   // !! private URL imgURL;

   private static Player player;

   public Player(int xl, int yl, boolean fire, String name) {
      BufferedImage img = new BufferedImage(20, 20, BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2 = img.createGraphics();
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
      g2.setColor(Color.red);
      g2.fillOval(2, 2, 16, 16);
      g2.dispose();
      imageicon = new ImageIcon(img);
      xLoc = xl;
      yLoc = yl;
      isFiring = fire;
      filename = name;
      // !! imgURL = getClass().getResource(name);
      // imageicon = new ImageIcon(imgURL);
   }

   public static Player getInstance() {
      if (player == null) {
         player = new Player(0, 0, false, "Dog.jpg");
      }
      return player;
   }

   public void fire() {

   }

   public int getX() {
      return xLoc;
   }

   public int getY() {
      return yLoc;
   }

   public void newX(int x) {
      xLoc = x;
   }

   public ImageIcon getImg() {
      return imageicon;
   }

   public void newImg(ImageIcon ii) {
      imageicon = ii;
   }

   // !! public URL getURL(){
   // return imgURL;
   // }
   // !! public void newURL(String n){
   // imgURL = getClass().getResource(n);
   // }
   public void updateObject() {
      // !! imageicon = new ImageIcon(imgURL);
      System.out.println("update object called");
   }
}

class MoveLR extends AbstractAction {
   private int moveVal;
   Player player;

   public MoveLR(int mv) {
      moveVal = mv;
      player = Player.getInstance();
      System.out.println("New MoveLR object made");
   }

   @Override
   public void actionPerformed(ActionEvent e) {
      // TODO Auto-generated method stub
      player.newX(player.getX() + moveVal);
      ((JPanel) e.getSource()).repaint();
      System.out.println("actionPerformed() called");
   }

}

class Fire extends AbstractAction {
   public Fire() {
      System.out.println("Fire created");
   }

   @Override
   public void actionPerformed(ActionEvent arg0) {
      System.out.println("Fire called");
   }
}

Upvotes: 4

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