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问Java键绑定的触发非常不一致
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Stack Overflow用户

提问于 2018-12-09 07:13:02

回答 1查看 38关注 0票数 1

我正在开发一个游戏，它有一个玩家，我想使用WASD移动。我决定使用键绑定来尝试解决我遇到的键侦听器的问题，即使在切换到键绑定之后，这个问题仍然在发生。问题是，即使按下这些键是在移动播放器，但在移动播放器几次之后，输入几乎完全停止工作。这发生在可能只有1/10的按键移动玩家的情况下。我能做错什么呢？任何帮助都将不胜感激。

下面是我的游戏的主类和键绑定：(如果我应该发布剩下的代码，请告诉我)

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.Color;  
import java.awt.Graphics;  
import javax.swing.JComponent;
import java.lang.Math;
import java.util.LinkedList;
import java.awt.event.KeyEvent;
import javax.swing.Action;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.KeyStroke;

public class ZombieMain extends JPanel implements ActionListener{

   private static int WIDTH = 1600;
   private static int HEIGHT = 900;

   private Action a,s,w,d,ra,rs,rw,rd;

   private LinkedList<Zombie> zombies = new LinkedList();
   Zombie z = new Zombie(100,100,50,30,50);
   static ZombiePlayer player = new ZombiePlayer(950,572,2,30);

   public ZombieMain(){
      this.setFocusable(true);
      this.requestFocus();

      Timer t = new Timer(10,this);
      t.start();

      Action w = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vY = -player.speed;
         }
      };
      Action s = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vY = player.speed;
         }
      };
      Action d = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vX = player.speed;
         }
      };
      Action a = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vX = -player.speed;
         }
      };
      Action rw = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vY = 0;
         }
      };
      Action rs = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vY = 0;
         }
      };
      Action rd = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vX = 0;
         }
      };
      Action ra = new AbstractAction() {
         public void actionPerformed(ActionEvent e) {
            player.vX = 0;
         }
      };

     getInputMap().put(KeyStroke.getKeyStroke("W"),"w");
     getInputMap().put(KeyStroke.getKeyStroke("S"),"s");
     getInputMap().put(KeyStroke.getKeyStroke("D"),"d");
     getInputMap().put(KeyStroke.getKeyStroke("A"),"a");
     getInputMap().put(KeyStroke.getKeyStroke("released W"),"rw");
     getInputMap().put(KeyStroke.getKeyStroke("released S"),"rs");
     getInputMap().put(KeyStroke.getKeyStroke("released D"),"rd");
     getInputMap().put(KeyStroke.getKeyStroke("released A"),"ra");

     getActionMap().put("w",w);
     getActionMap().put("s",s);
     getActionMap().put("d",d);
     getActionMap().put("a",a);
     getActionMap().put("rw",rw);
     getActionMap().put("rs",rs);
     getActionMap().put("rd",rd);
     getActionMap().put("ra",ra);
   }

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

   public void paint(Graphics g){
      g.setColor(new Color(40,40,40));
      g.fillRect(0,0,WIDTH,HEIGHT);
      z.draw((Graphics)g);
      player.draw((Graphics)g);
   }

   public int getWidth(){
      return WIDTH;
   }
   public int getHeight(){
      return HEIGHT;
   }
   public static void main(String[] args){
        JFrame frame = new JFrame();
        frame.add(new ZombieMain());
        frame.setSize(WIDTH,HEIGHT);  
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    
        frame.setVisible(true);
        frame.setResizable(false);
   }
}

key-bindings

keyevent

java

swing

jpanel

回答 1

Stack Overflow用户

发布于 2018-12-09 08:16:10

至于“为什么”你有问题，我只能猜测，因为我们只有一个脱离上下文的片段要处理，然而，有许多事情可以改进，这可能有助于解决问题。

调用getInputMap时的

User WHEN_IN_FOCUSED_WINDOW

这适用于何时实际触发按键事件的上下文，在上述情况下，无论当前哪个组件具有键盘焦点，只要窗口有焦点，就会触发按键事件。

与paint相比，

更喜欢覆盖paintComponent

Swing中的绘画有些复杂，正如一般建议的那样，当你想要执行自定义绘画时，最好覆盖paintComponent。这样做的一个很好的副作用是，它将为您的组件绘制背景颜色，您需要做的事情就少了一件;)

当您需要为

提供大小调整提示时，

首选覆盖getPreferredSize

覆盖getWidth和getHeight将会导致无休止的问题，最好避免。相反，覆盖getPreferredSize，这样，您就参与到了布局应用程序接口中，并获得了它的所有优势，例如能够在JFrame上调用pack，并让它处理围绕框架装饰的所有奇怪之处。

将状态的更改与用于影响该状态的机制分开

“解耦你的代码”这句话用得很好。在您的代码中，播放器的状态直接由按键操作更改。这不仅是一个糟糕的想法，而且可能会产生意想不到的副作用，并且随着需求变得越来越复杂，管理也会变得越来越困难。这也使得改变输入的方式变得困难。例如，您可以包含不同的输入方法，例如操纵杆，但是您必须为它编写相同的代码。

相反，你应该有一个简单的“状态管理器”，它携带输入的当前状态，当你的“主循环”准备好时，它会将该状态作为单独的步骤应用到模型中。

“主循环”并不关心状态是如何更新的，只关心它可以获得所需的信息来决定如何应用它。

下面是我上面讨论的所有内容的粗略示例，在我的测试中，我没有遇到绑定“拖延”的问题。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;

public class ZombieMain extends JPanel implements ActionListener {

    enum VerticalDirection {
        UP, DOWN, NONE
    }

    enum HorizontalDirection {
        LEFT, RIGHT, NONE
    }

    public class VerticalStateController {

        private VerticalDirection state = VerticalDirection.NONE;

        public void setState(VerticalDirection state) {
            this.state = state;
        }

        public VerticalDirection getState() {
            return state;
        }

    }

    public class HorizontalStateController {

        private HorizontalDirection state = HorizontalDirection.NONE;

        public void setState(HorizontalDirection state) {
            this.state = state;
        }

        public HorizontalDirection getState() {
            return state;
        }

    }

    public class VerticalAction extends AbstractAction {

        private VerticalStateController controller;
        private VerticalDirection state;

        public VerticalAction(VerticalStateController controller, VerticalDirection state) {
            this.controller = controller;
            this.state = state;
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            controller.setState(state);
        }

    }

    public class HorizontalAction extends AbstractAction {

        private HorizontalStateController controller;
        private HorizontalDirection state;

        public HorizontalAction(HorizontalStateController controller, HorizontalDirection state) {
            this.controller = controller;
            this.state = state;
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            controller.setState(state);
        }

    }

    private static int WIDTH = 400;
    private static int HEIGHT = 400;

    private Rectangle player = new Rectangle(0, 0, 20, 20);
    private VerticalStateController verticalStateController = new VerticalStateController();
    private HorizontalStateController horizontalStateController = new HorizontalStateController();

    public ZombieMain() {
        setBackground(new Color(40, 40, 40));

        Timer t = new Timer(10, this);
        t.start();

        InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
        ActionMap am = getActionMap();

        // Pressed
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0, false), "Pressed.up");
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0, false), "Pressed.down");
        // Released
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0, true), "Released.up");
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0, true), "Released.down");

        // Pressed
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0, false), "Pressed.left");
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0, false), "Pressed.right");
        // Released
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0, true), "Released.left");
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0, true), "Released.right");

        am.put("Pressed.up", new VerticalAction(verticalStateController, VerticalDirection.UP));
        am.put("Pressed.down", new VerticalAction(verticalStateController, VerticalDirection.DOWN));
        am.put("Released.up", new VerticalAction(verticalStateController, VerticalDirection.NONE));
        am.put("Released.down", new VerticalAction(verticalStateController, VerticalDirection.NONE));

        am.put("Pressed.left", new HorizontalAction(horizontalStateController, HorizontalDirection.LEFT));
        am.put("Pressed.right", new HorizontalAction(horizontalStateController, HorizontalDirection.RIGHT));
        am.put("Released.left", new HorizontalAction(horizontalStateController, HorizontalDirection.NONE));
        am.put("Released.right", new HorizontalAction(horizontalStateController, HorizontalDirection.NONE));
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(WIDTH, HEIGHT);
    }

    public void actionPerformed(ActionEvent e) {
        switch (verticalStateController.getState()) {
            case UP:
                player.y -= 4;
                break;
            case DOWN:
                player.y += 4;
                break;
        }
        switch (horizontalStateController.getState()) {
            case LEFT:
                player.x -= 4;
                break;
            case RIGHT:
                player.x += 4;
                break;
        }
        repaint();
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g.create();
        g2d.setColor(Color.RED);
        g2d.fill(player);
        g2d.dispose();
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new ZombieMain());
                frame.pack();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

我应该指出，这只是一种方法。我还可以在某种类型的Set中放置一堆“标志”

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/53687927

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