我如何在java中使用KeyListener？ [英] How do i use KeyListener in java?

问题描述

如何在此代码上使用KeyListener进行上下移动？我知道如何使用KeyListener，但我不知道它在这个代码上的位置。

How do I use KeyListener on this code to move up and down? Ii know how to use KeyListener but I don't know where it put it on this code.

    import java.awt.*;
    import java.awt.image.*;
    import java.awt.event.*;
    import java.awt.geom.*;

    import javax.swing.*;


    public class ControlPanel extends JPanel implements Runnable,ActionListener,KeyListener,MouseListener{
        private MainPanel main;
        private final static int maxWidth = 800, maxHeight = 600; //width & height of JPanel
        private boolean running; //keeps track of state of the program
        private Thread thread;
        private Graphics2D graphics;
        private Image image; //used for double buffering
        private BufferedImage bgImage;
        private String s = "";
        Font f = new Font("Times New Roman",Font.PLAIN,50);
        Timer t = new Timer(2000,this);
        private int typed = 0;
        private int x = 50,y = 500;

        public ControlPanel(MainPanel main) {
            this.setDoubleBuffered(false); //we'll use our own double buffering method
            this.setBackground(Color.black);
            this.setPreferredSize(new Dimension(maxWidth, maxHeight));
            this.setFocusable(true);
            this.requestFocus();
            this.main = main;
            addKeyListener(this);
            addMouseListener(this);
            t.start();
        }

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

        public void addNotify() {
            super.addNotify();
            startGame();
        }

        public void stopGame() {
            running = false;
        }

        //Creates a thread and starts it
        public void startGame() {
            if (thread == null || !running) {
                thread = new Thread(this);
            }
            thread.start(); //calls run()
        }

        public void run() {
            running = true;

            init();
            while (running) {
                createImage(); //creates image for double buffering

                ///////////////USE THESE 2 METHODS////////////////////
                update(); //use this to change coordinates, update values, etc


                draw(); //use this to draw to the screen


                //////////////////////////////////////////////////////
                drawImage(); //draws on the JPanel
            }

            System.exit(0);
        }





        //Use this to create or initialize any variables or objects you have
        public void init() {
        }
         public void initGame(){

         }



        //Use this to update anything you need to update
        public void update() {

        }

        //Use this to draw anything you need to draw
        public void draw() {        

            graphics.setColor(Color.WHITE);
            graphics.fillRect(250, 450, 300,100);

            graphics.setColor(Color.WHITE);
            graphics.fillRect(250, 320, 300,100);

            graphics.setColor(Color.GREEN);
            graphics.setFont(f);
            graphics.drawString(s, x, y);
            typed = 0;

            graphics.setFont(f);
            graphics.setColor(Color.blue);
            graphics.drawString("HANGMAN", 270,75);

            graphics.setFont(f);
            graphics.setColor(Color.blue);
            graphics.drawString("PLAY", 330, 390);

            graphics.setFont(f);
            graphics.setColor(Color.blue);
            graphics.drawString("QUIT", 330, 520);

            graphics.setColor(Color.red);
            graphics.drawRect(248, 318, 304,104);




        }

        //creates an image for double buffering
        public void createImage() {
            if (image == null) {
                image = createImage(maxWidth, maxHeight);

                if (image == null) {
                    System.out.println("Cannot create buffer");
                    return;
                }
                else
                    graphics = (Graphics2D)image.getGraphics(); //get graphics object from Image
            }

            if (bgImage == null) {
                graphics.setColor(Color.black);
                graphics.fillRect(0, 0, maxWidth, maxHeight);
                //System.out.println("No background image");
            }
            else {
                //draws a background image on the Image
                graphics.drawImage(bgImage, 0, 0, null);
            }
        }

        //outputs everything to the JPanel
        public void drawImage() {
            Graphics g;
            try {
                g = this.getGraphics(); //a new image is created for each frame, this gets the graphics for that image so we can draw on it
                if (g != null && image != null) {
                    g.drawImage(image, 0, 0, null);
                    g.dispose(); //not associated with swing, so we have to free memory ourselves (not done by the JVM)
                }
                image = null;
            }catch(Exception e) {System.out.println("Graphics objects error");}
        }


        public void actionPerformed(ActionEvent e) {
            // TODO Auto-generated method stub

        }

        public void keyPressed(KeyEvent e) {    



        }

        public void keyReleased(KeyEvent e) {


        }

        public void keyTyped(KeyEvent e) {
            typed = 1;

            s+=Character.toString(e.getKeyChar());
            s+=" ";
            System.out.println(s);
        }

        @Override



        public void mouseClicked(MouseEvent e) {
            System.out.println(e.getPoint());

        }

        @Override
        public void mouseEntered(MouseEvent arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void mouseExited(MouseEvent arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void mousePressed(MouseEvent arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void mouseReleased(MouseEvent arg0) {
            // TODO Auto-generated method stub

        }
    }

推荐答案

KeyListener 未指定用于监听 SW对于JComponents ，请改用 KeyBindings ，输出到Swing GUI应来自 Swing Action

KeyListener isn‘t designated for listening of keyboard events for Swing JComponents, use KeyBindings instead, output to the Swing GUI should be from Swing Action

这篇关于我如何在java中使用KeyListener？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！