Question

我让蛇跑了，现在我试着让keypressed（）方法起作用。我不认为它是从键盘上听的。我的想法是，例如，如果按下向下键，变量direction设置为1，switch case语句将处理它。我怀疑开关盒没有读取方向变量。

我的主要课程：

package com.bin.snake;

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JFrame;
import javax.swing.JPanel;

@SuppressWarnings("serial")
public class Game extends JPanel{

boolean playingSnake = true;
Snake snake = new Snake();

public Game() {
    addKeyListener(new KeyListener() {

        @Override
        public void keyTyped(KeyEvent e) {
            // TODO Auto-generated method stub

        }

        @Override
        public void keyReleased(KeyEvent e) {
            // TODO Auto-generated method stub

        }

        @Override
        public void keyPressed(KeyEvent e) {

            snake.keyPressed(e);
        }
    });
    setFocusable(true);
}

public void paint(Graphics g) {// inherit paint method of JPanel class with
    // parameter g type Graphics
    // parameter g is the object to paint things
    super.paint(g); // erase latest image
    Graphics2D g2d = (Graphics2D) g; // casting g to Graphics2D type
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,      RenderingHints.VALUE_ANTIALIAS_ON);// rendering
                                                                                                // image
    snake.paint(g2d);

}

public static void main(String[] args) {
    JFrame frame = new JFrame("Snake!");
    frame.setVisible(true);
    frame.setSize(800, 600);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    Game game = new Game();
    frame.add(game);
    while (true) {
        game.updateGame();
        game.repaint();
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

public void updateGame() {
    snake.moveSnake();
}

}

我的蛇类：

package com.bin.snake;

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

public class Snake {

private Game game;
int iSnakeLength = 10;
int direction = 1;
final int SIDE = 13;

int[] snakeY = new int[2000];
int[] snakeX = new int[2000];
int xs = 0;
int ys = 0;

public void moveSnake() {

    switch (direction) {
    case 0:// up
        snakeY[0] -=1.5;
        break;
    case 1:// down
        snakeY[0] += 1.5;
        break;
    case 2:// right
        snakeX[0] += 1.5;
        break;
    case 3:// left
        snakeX[0] -=1.5;
        break;
    }

    for (int i = iSnakeLength; i > 0; i--) {
        snakeX[i] = snakeX[i - 1];
        snakeY[i] = snakeY[i - 1];

    }
}

public void paint(Graphics2D g) {
    g.fillRect(snakeX[0], snakeY[0], SIDE, SIDE);
    for (int i = 0; i < iSnakeLength; i++) {
        g.fillRect(snakeX[i + 1], snakeY[i + 1], SIDE, SIDE);
    }

}

public void keyPressed(KeyEvent e){
    if(e.getKeyCode() == KeyEvent.VK_DOWN){
        direction = 1;
    }
    if(e.getKeyCode() == KeyEvent.VK_UP){
        direction = 0;
    }
    if(e.getKeyCode() == KeyEvent.VK_LEFT){
        direction = 3;
    }
    if(e.getKeyCode() == KeyEvent.VK_RIGHT){
        direction = 2;
    }
}

}

Answer 1

我不认为它是从键盘上听的。我的想法

仅将KeyEvents分派给具有焦点的组件。默认情况下，JPanel无法调焦。

要使面板具有焦点，请使用：

panel.setFocusable( true );

其他评论：

自定义绘制是通过覆盖paintComponent(...)方法而不是paint（）方法完成的。阅读Custom Painting上的Swing教程，了解更多信息和示例。
您不应该使用KeyListener。 Swing旨在与Key Bindings一起使用。阅读How to Use Key Bindings上的Swing教程。您还可以查看Motion Using the Keyboard，其中包含使用键绑定移动组件的工作示例。
对于动画，您应该使用Swing Timer来安排动画。检查我已经提供的教程链接中的目录。 How to Use Swing Timers上有一节。

蛇游戏。处理keyPressed方法

1 个答案: