我怎样才能让这个玩家移动？

Question

So I am trying to make my own version of the Pong game. My problems with this program is that my player doesn't move. I think I made a mistake but because I am really new to java I don't fully understand game mechanics in code. Could one of you please review my code carefully and tell me whats wrong and how to correct it. Also, would one of you tell me where did you learn or where can I learn game development with Java. Your answers will be really appreciated.

Window Class

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

public class Window{
  public Window(){
    JFrame window = new JFrame();
    GamePanel gamePanel = new GamePanel();
    window.setSize(720, 480);
    window.setResizable(true);
    window.setTitle("2DGame");
    window.add(gamePanel);
    window.setUndecorated(false);
    window.setLocationRelativeTo(null);
    window.getContentPane().setBackground(Color.BLACK);
    window.setVisible(true);
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    window.setMinimumSize(new Dimension(720, 480));
  }
}

GamePanel Class

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

public class GamePanel extends JPanel{
  Wall wall = new Wall();
  Player player = new Player();
  public GamePanel(){
    setBackground(new Color(16, 16, 16));
  }
  public void paintComponent(Graphics g){
    super.paintComponent(g);
    wall.paintComponent(g);
    player.paintComponent(g);
  }
}

Player Class

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Player extends JPanel implements ActionListener, KeyListener{
  Timer t = new Timer(5, this);
  private int x = 28;
  private int y = 190;
  private int ydirection;
  private int speed = 1;
  public Player(){
    t.start();
    addKeyListener(this);
    setFocusable(true);
    setFocusTraversalKeysEnabled(false);
  }
  public void paintComponent(Graphics g){
    g.setColor(Color.WHITE);
    g.fillRect(x, y, 20, 100);
  }
  public void actionPerformed(ActionEvent e){
    y += ydirection;
    repaint();
  }
  public void keyPressed(KeyEvent e){
    int KeyCode = e.getKeyCode();
    if(KeyCode == KeyEvent.VK_W){
      ydirection -= speed;
    }
    if(KeyCode == KeyEvent.VK_S){
      ydirection += speed;
    }
  }
  public void keyReleased(KeyEvent e){
    int KeyCode = e.getKeyCode();
    if(KeyCode == KeyEvent.VK_W){
      ydirection = 0;;
    }
    if(KeyCode == KeyEvent.VK_S){
      ydirection = 0;
    }
  }
  public void keyTyped(KeyEvent e){}
}

Answer 1

Your logic is not entirely good, but you can easily fix it. Please study the OOP (principle). For example:

• The player is not JPanel.
• The ActionListener and KeyListener interface management is not the Player class job, please create a separate class for her.
• Please study the access modifiers.

Pay more attention to the transparency of your code. For example:

• Use the ovverride annotation.
• Use the formatter(Ctrl + Shift + F in eclipse)

The problem was that you wrote Keylistener on another Jpanel. What I think you inadvertently put on the player class. I quickly reworked the code a bit.

Window class:

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

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

public class Window {
    public Window() {
        JFrame window = new JFrame();
        GamePanel gamePanel = new GamePanel();
        window.setSize(720, 480);
        window.setResizable(true);
        window.setTitle("2DGame");
        window.add(gamePanel);
        window.setUndecorated(false);
        window.setLocationRelativeTo(null);
        window.getContentPane().setBackground(Color.BLACK);
        window.setVisible(true);
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setMinimumSize(new Dimension(720, 480));
    }

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

PlayerDirections enum:

public enum PlayerDirections {
    UP, DOWN
}

Player class:

import java.awt.Color;
import java.awt.Graphics;

public class Player {
    private int x = 28;
    private int y = 190;
    private int speed = 1;

    public Player() {

    }

    public void draw(Graphics g) {
        g.setColor(Color.WHITE);
        g.fillRect(x, y, 20, 100);
    }

    public void Move(PlayerDirections direction) {
        switch (direction) {
        case UP:
            y -= speed;
            break;
        case DOWN:
            y += speed;
            break;
        }
    }

}

GamePanel class:

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import javax.swing.JPanel;
import javax.swing.Timer;

public class GamePanel extends JPanel implements ActionListener {

    Player player = new Player();

    public GamePanel() {
        addKeyListener(new KeyAdapter() {
            @Override
            public void keyPressed(KeyEvent e) {
                int KeyCode = e.getKeyCode();
                if (KeyCode == KeyEvent.VK_W) {
                    player.Move(PlayerDirections.UP);
                }
                if (KeyCode == KeyEvent.VK_S) {
                    player.Move(PlayerDirections.DOWN);
                }
            }
        });
        setFocusable(true);
        setFocusTraversalKeysEnabled(false);
        setBackground(new Color(16, 16, 16));
        Timer t = new Timer(5, this);
        t.start();
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        player.draw(g);

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        repaint();
    }
}