有人可以告诉我如何在以下代码中获取int x的值: 当我左右移动方格时,Test的输出保持为500。
我希望Thread in Test在每次循环时获取x的值,但x总是500(来自线程),即使x的值在Drawing.java中发生了变化。请帮帮我。
package block;
public class Test extends Drawing implements Runnable{
Thread collision = new Thread(this);
public Test() {
collision.start();
}
@Override
public void run() {
while(true) {
System.out.println(x);
}
}
}
package block;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.logging.Level;
import java.util.logging.Logger;
public class Drawing extends Canvas implements Runnable, KeyListener{
Thread thread = new Thread(this);
int x = 500;
int y = 540;
public Drawing() {
setSize(1000, 800);
addKeyListener(this);
thread.start();
}
public void update(Graphics g) {
g.setColor(Color.WHITE);
g.fillRect(0, 0, 1000, 700);
paint(g);
}
public void paint(Graphics g) {
g.setColor(Color.cyan);
g.fillRect(x, y, 50, 50);
}
@Override
public void run() {
while(true) {
repaint();
try {
Thread.sleep(100);
} catch (InterruptedException ex) {
Logger.getLogger(Drawing.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
@Override
public void keyTyped(KeyEvent ke) {
}
@Override
public void keyPressed(KeyEvent ke) {
if(ke.getKeyCode() == KeyEvent.VK_LEFT) {
x -= 5;
}
if(ke.getKeyCode() == KeyEvent.VK_RIGHT) {
x += 5;
}
}
@Override
public void keyReleased(KeyEvent ke) {
}
}
编辑:--------------------
package block;
import javax.swing.JFrame;
public class Block extends JFrame{
Test test = new Test();
public Block() {
setSize(1000, 700);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
add(new Drawing());
setVisible(true);
createBufferStrategy(2);
}
public static void main(String[] args) {
new Block();
}
}
答案 0 :(得分:2)
您正在创建x
的多个实例,因为您没有正确使用继承。当您致电new Test()
时,会创建Test
的一个实例(其中包含Drawing
,其中包含成员x
),然后调用{{1} }创建new Drawing()
的另一个实例(其中包含不同的成员Drawing
)。
要解决此问题,您可以将引用传递给x
构造函数的Drawing
对象,并通过引用访问Test
成员。< / p>