java - 需要帮助让我的按键监听器脱离主线程

Question

我已经开始制作一款可以自由移动的游戏。你用你的键盘移动我让它工作，但我想做的就是把它从 main 中取出，这样我就可以从不同的类多次调用。我尝试将其放入 public static void 中并从 main 调用该方法，但它不起作用。下面提供了我的代码。我已经被困在这个问题上很长一段时间了。

我在框架中有一张图片以使其可见，该图片名为 1。

import java.awt.event.KeyEvent;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.*;
public class StartGame {
    public static void main(String[] argv) throws Exception {
        JFrame MainFrame = new JFrame();
        MainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        MainFrame.setSize(1210, 700);
        MainFrame.setLocation(new java.awt.Point(150, 30));
        MainFrame.setLayout(null);
        MainFrame.setFocusable(true);
        MainFrame.setFocusTraversalKeysEnabled(true);
        MainFrame.setIconImage(new ImageIcon("images\\sword.png").getImage());
        JLabel thing = new JLabel();
        thing.setIcon(new ImageIcon("image\\1.gif"));
        thing.setBounds(300, 300, thing.getPreferredSize().width, thing.getPreferredSize().height);

        MainFrame.addKeyListener(new java.awt.event.KeyListener() {
            public void keyPressed(KeyEvent e) {
                if (e.getKeyCode() == KeyEvent.VK_UP || e.getKeyCode() == KeyEvent.VK_W) {
                    if (0 < thing.getY()) { 
                        thing.setLocation(thing.getX(), thing.getY() - 10);
                    }
                }
                if (e.getKeyCode() == KeyEvent.VK_DOWN || e.getKeyCode() == KeyEvent.VK_S) {
                    if (thing.getY() < 570) {
                        thing.setLocation(thing.getX(), thing.getY() + 10);
                    }
                }
                if (e.getKeyCode() == KeyEvent.VK_RIGHT || e.getKeyCode() == KeyEvent.VK_D) {
                    if (thing.getX() < 1110) {
                        thing.setLocation(thing.getX()+ 10, thing.getY());
                    }
                }
                if (e.getKeyCode() == KeyEvent.VK_LEFT || e.getKeyCode() == KeyEvent.VK_A) {        
                    if (0 < thing.getX()) {
                        thing.setLocation(thing.getX() - 10, thing.getY());
                    }
                }

            }

            public void keyTyped(KeyEvent e) {

            }

            public void keyReleased(KeyEvent e) {


            }
        });

        MainFrame.add(thing);
        MainFrame.setVisible(true);
    }
}

Answer 1

不要使用KeyListener，使用key bindings API 。使用按键绑定(bind) API 将允许您在“窗口”级别而不是组件级别响应按键事件(如果您愿意)

例如...

import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.ImageIcon;
import javax.swing.InputMap;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.KeyStroke;

public class StartGame {

    public static void main(String[] argv) throws Exception {
        JFrame mainFrame = new JFrame();
        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainFrame.setSize(1210, 700);
        mainFrame.setLocation(new java.awt.Point(150, 30));
        mainFrame.setLayout(null);
        mainFrame.setFocusable(true);
        mainFrame.setFocusTraversalKeysEnabled(true);
        mainFrame.setIconImage(new ImageIcon("images\\sword.png").getImage());
        JLabel thing = new JLabel("X");
        //thing.setIcon(new ImageIcon("image\\1.gif"));
        thing.setBounds(300, 300, thing.getPreferredSize().width, thing.getPreferredSize().height);

        InputMap inputMap = thing.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
        ActionMap actionMap = thing.getActionMap();

        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, false), "move.up");
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0, false), "move.up");
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, false), "move.down");
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0, false), "move.down");
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0, false), "move.left");
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0, false), "move.left");
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0, false), "move.right");
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0, false), "move.right");

        actionMap.put("move.up", new ThingAction(thing, new Point(0, -1)));
        actionMap.put("move.down", new ThingAction(thing, new Point(0, 1)));
        actionMap.put("move.left", new ThingAction(thing, new Point(-1, 0)));
        actionMap.put("move.right", new ThingAction(thing, new Point(1, 0)));

        mainFrame.add(thing);
        mainFrame.setVisible(true);
    }

    public static class ThingAction extends AbstractAction {
        private JLabel thing;
        private Point delta;

        public ThingAction(JLabel thing, Point delta) {
            this.thing = thing;
            this.delta = delta;
        }

        @Override
        public void actionPerformed(ActionEvent arg0) {
            thing.setLocation(thing.getX() + delta.x, thing.getY() + delta.y);
        }
    }
}

这是一个非常基本的示例，但它演示了两个关键点:

1. 您可以为单个操作分配多个键
2. 您可以将输入(即键盘)与实现分离，这意味着您可以使用相同的基本 Action 来处理鼠标输入或操纵杆输入