keylistener和runnable不能正常工作

Question

你能看到問題嗎？線程運行良好，但磚塊不想響應關鍵偵聽器。我嘗試測試，如果keylistener的病情終於能一個事件，但它甚至沒有做system.out.println

import java.awt.*;//imports 
import java.util.*; 
import java.applet.*; 
import java.awt.event.KeyListener; 
import java.awt.event.KeyEvent; 

public class Start extends Applet implements Runnable, KeyListener// where i put the keylistener in 
{ 

    DrawBackground dbg = new DrawBackground(); 
    Brick brick = new Brick(); 
    Thread gameLoop; 

    public void init() { 
     addKeyListener(this);// i add the key listener 
    } 

    public void start() { 
     Thread gameLoop = new Thread(this); 
     gameLoop.start(); 
    } 

    public void run() { 
     while (true) { 

      brick.update(1); 
      repaint(); 
      try { 
       Thread.sleep(17); 
      } 
      catch (InterruptedException e) { 
      } 

     } 
    } 

    public void stop() { 

    } 

    public void paint(Graphics g)// with out any paint it works if im changing 
           // somthing like a lable 
    { 
     dbg.paint(g, this); 
     brick.paint(g, this); 
    } 

    public void keyPressed(KeyEvent e)// test to see if it works 
    { 
     System.out.println("why"); 
     if (e.getKeyCode() == 37) { 
      brick.left(); 
     } 
    } 

    public void keyTyped(KeyEvent e) { 
    } 

    public void keyReleased(KeyEvent e) { 

    } 
} 

這是磚類我想要的東西移動

import java.awt.*; 
import java.util.*; 
import java.applet.*; 

public class Brick { 

    public int dy = 40; 
    public int yStart = -20; 
    public int time = 0; 
    public int dx = 0; 
    public int xStart = 0; 
    public int start = 1; 

    public void paint(Graphics g, Start sp) { 
     Dimension screenSize = sp.getSize(); 
     int sheight = screenSize.height; 
     int swidth = screenSize.width; 
     if (start == 1) { 
      xStart = swidth - (int) (swidth/2.5); 
      start = 0; 
     } 
     int bWidth = swidth/15; 
     int bHeight = swidth/15; 
     int time = 0; 
     g.setColor(Color.red); 
     g.fillRect(xStart, yStart, bWidth, bHeight); 
    } 

    public void update(int x) { 
     if (time == 60) { 
      time = 0; 
      yStart += dy; 
     } 
     else { 
      time += x; 
     } 
    } 

    public void left() { 
     xStart -= dx; 
    } 
} 

Answer 1

一點也沒有看起來你已經設置了鍵盤焦點。請參閱this question.

我一直在使用setFocusable(true)在添加keyListener併爲其工作之後，但該問題的答案有更好的解決方案。