Java如何不断重画

Question

我正在努力制作游戏Snake，尽管我现在无法重新粉刷蛇。 我正在使用计时器，当我将间隔设置为150毫秒时，它可以正常工作，但是当我将它设置为更快的速度（如30毫秒）时，屏幕上没有任何显示。 带有repaint（）调用的计时器在Game类中。 谢谢！

游戏类

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.*;
import java.util.*;
import java.util.Timer;
import java.util.TimerTask;

public class Game extends JFrame{

    JPanel mainPanel = new JPanel();

    BorderLayout layout = new BorderLayout();
    //Game game;
    Snake snake = new Snake(this);

    public Game(){

        super("Snake by Alex 2017");
        setSize((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth()),(int)(Toolkit.getDefaultToolkit().getScreenSize().getHeight()));
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);

        mainPanel.setLayout(null);
        mainPanel.setSize((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth()),(int)(Toolkit.getDefaultToolkit().getScreenSize().getHeight()));
        mainPanel.setBackground(Color.BLACK);
        add(mainPanel);
        mainPanel.setVisible(true);

        start();

        addKeyListener(new KeyListener() {

            @Override
            public void keyTyped(KeyEvent e) {
            }

            @Override
            public void keyReleased(KeyEvent e) {
            }

            @Override
            public void keyPressed(KeyEvent e) {
                snake.keyPressed(e);

            }
        });
        setFocusable(true);



    }

    public void paint(Graphics g){
        super.paint(g);
        Graphics2D g2d = (Graphics2D) g;
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        snake.paint(g2d);

        //System.out.println("hello");

    }

    Timer timer = new Timer();
    TimerTask task = new TimerTask() {
        public void run() {
            try {
                move();
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    };
    TimerTask update = new TimerTask() {

        public void run() {
            repaint();

        }
    };
    public void start(){
        timer.scheduleAtFixedRate(task, 0, 250);
        timer.schedule(update, 0, 30);

    }

    public void move() throws InterruptedException{
        snake.move();

    }

    public static void main(String[] args) throws InterruptedException{
        Game game = new Game();


    }

}

蛇类

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;

import javax.swing.RepaintManager;

public class Snake {

    public int x = 60;
    public int y = 80;
    public int xa = 0;
    public int ya = 0;
    public int speed = 20;
    private Game game;

    public Snake(Game game){
        this.game = game;
    }

    public void move(){
        x += xa;
        y += ya;
    }

    public void keyPressed(KeyEvent e){
        //RIGHT
        if(e.getKeyCode() == 39){
            xa = speed;
            ya = 0;
        }
        //LEFT
        if(e.getKeyCode() == 37){
            xa = -speed;
            ya = 0;
        }
        //UP
        if(e.getKeyCode() == 38){
            ya = -speed;
            xa = 0;
        }
        //DOWN
        if(e.getKeyCode() == 40){
            ya = speed;
            xa = 0;
        }
        //move();
        //game.repaint();

    }
    public Rectangle getBounds(){
        return new Rectangle(x, y, 20, 20);
    }
    public void paint(Graphics2D g2d){
        g2d.setColor(new Color(48, 255, 55));
        g2d.fillRect(x, y, 20, 20);

    }

}

Answer 1

你要做的就是创建一个一直循环并呈现游戏的线程，如：

public void run() {
    while (true) {
        render();
    }
}

你的run方法是正确的，但是你还需要一次又一次地在一个额外的线程中扩展Thread来重新显示多线程的这篇文章 。

有关BufferStrategy等的所有细节，请参阅本教程 。 我认为它解释得非常好，我用它自己。

Answer 2

尝试使用javax.swing.Timer; 如https://docs.oracle.com/javase/tutorial/uiswing/misc/timer.html中所述实现ActionListener并将其放在repaint() ，然后像这样创建Timer

Timer timer = new Timer(5, this);
        timer.start();

这将调用actionPerformed() ，你有repaint()