java - 一旦达到某个障碍，如何停止动画？

Question

今天困扰我的问题就是这样。我正在创建一个程序，允许用户跳跃并向左或向右移动，问题是每当我尝试跳跃时程序就会卡住...我的代码背后的想法很简单，每当用户按下空格(跳跃)时矩形“跳”起来，如果矩形的 y 位于障碍物上方一定高度内(在本例中，尺寸为 brickx、bricky、brickw 的矩形，brickh 是障碍物)，则动画应该停止，并且矩形应该在障碍物顶部等待下一个命令。为此，在 while 循环的每次迭代期间调用stayOnBrick 方法并进行检查；在跳转过程中，如果 y 在所需的范围内，并且如果 y 是则设置 boolean 跳转 = true ，这应该在下一次迭代中打破循环并将 y 设置为所需的值。但是当按下空格时，什么也没有发生，或者我应该说程序卡住了。想法？

import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

public class KeyTest extends Core implements KeyListener{
    Window w;
    public int x,y;
    boolean jump = true;
    public int brickx, bricky, brickw, brickh;
    public static void main(String args[]){
        new KeyTest().run();
    }

    private String mess = "";

    //init also called init from superclass
    public void init(){
        super.init();
        Window w = s.getFullScreenWindow();
        w.setFocusTraversalKeysEnabled(false);
        w.addKeyListener(this);
        y = s.getHeight()-15;
        mess = "Press esc to exit";
    }


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

    @Override
    public void keyPressed(KeyEvent e) {

        // TODO Auto-generated method stub
        int keyCode = e.getKeyCode();
        if(keyCode == KeyEvent.VK_ESCAPE){
            stop();
        }else if(keyCode == KeyEvent.VK_SPACE){
            mess = "Pressed: " + KeyEvent.getKeyText(keyCode);
            while(y>s.getHeight()-200){
                stayOnBrick();
                if(jump==false){break;}
                else{   try{
                    y-=20;
                    w.repaint();
                    Thread.sleep(40);
                }catch(Exception jumpError){
                    System.out.println("Error in Jumping");
                    }
                }

            while(y<s.getHeight()-15){
                stayOnBrick();
                if(jump==false){
                    w.repaint();
                    break;}
                else{
                try{
                    y+=20;
                    Thread.sleep(40);
                    w.repaint();
                }catch(Exception jumpError){
                    System.out.println("Error in Jumping");
                        }
                    }
                }
            }
        }

        else if(keyCode == e.VK_RIGHT){
            if(x>=s.getWidth()-30){x=s.getWidth()-30;}
                x+=20;
                w.repaint();
            }
        else if(keyCode == e.VK_LEFT){
            if(x<=0){x=0;}
            x-=20;
            w.repaint();
        }

        e.consume();
    }


    @Override
    public void keyReleased(KeyEvent e) {
        // TODO Auto-generated method stub
        int keyCode = e.getKeyCode();
        mess = "Released: " + KeyEvent.getKeyText(keyCode);
        jump = true;
        e.consume();
    }
    @Override
    public synchronized void draw(Graphics2D g){
        brickx=0; bricky=s.getHeight()-100; brickw=300; brickh=20;
        Window w = s.getFullScreenWindow();
        g.setColor(w.getBackground());
        g.fillRect(0, 0, s.getWidth(), s.getHeight());
        g.setColor(w.getForeground());
        g.fillRect(x, y, 30, 15);
        g.drawString(mess, 30, 30);
        g.setColor(Color.BLUE);
        g.fillRect(brickx, bricky, brickw, brickh);


    }

    public void stayOnBrick(){
        if(y<bricky && y>bricky-30){
            y=bricky-15;
            jump = false;   
        }
        else{jump = true;}
    }
}  

Answer 1

whenever I try to jump the program freezes

我首先看一下 Concurrency in Swing问题的原因。

我建议看看How to use Swing Timers寻找可能的解决方案。

我还建议您查看 How to Use Key Bindings使用 KeyListener

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