Question

java键盘事件问题

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

public class Test
{
public static void main(String args[])
{
new S();

}
}

class S extends Frame implements KeyListener
{
S()
{
this.addKeyListener(this);
this.setSize(200,200);
this.setVisible(true);
}

public void keyPressed(KeyEvent e)
{
if(e.getKeyCode() == 38 && e.getKeyCode() == 39) //为什么我同时按住了向上和向右键不会输出这句话？ 如果这样做不行，应该怎么改？求高手！
{
System.out.println("你按了向上键和向右键");

}
}

public void keyReleased(KeyEvent e) {}
public void keyTyped(KeyEvent e) {}

}

Answer 1

if (e.getKeyCode() == 38 && e.getKeyCode() == 39)

不会同时满足这样的条件是
应该改成或的关系

if (e.getKeyCode() == 38 || e.getKeyCode() == 39)

Answer 2

虽然人的感觉是两个按钮同时按了，但是程序还是会分先后的，所以程序不可能同时收到两个事件，需要另外的方法处理，一般引入一个判断的标志就行了
import java.awt.Frame;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

public class Test
{
public static void main(String args[])
{
new S();

}
}

class S extends Frame implements KeyListener
{
private int flag;
S()
{
flag = 0;
this.addKeyListener(this);
this.setSize(200,200);
this.setVisible(true);
}

public void keyPressed(KeyEvent e)
{
if(e.getKeyCode() == 38 || e.getKeyCode() == 39)
{
flag += e.getKeyCode();
}
if(flag == 77)
{
System.out.println("你同时按了向上键和向右键");
}

}

public void keyReleased(KeyEvent e) {
flag = 0;
}
public void keyTyped(KeyEvent e) {}

}

Answer 3

你需要保存以前按得键
boolean up = false; //向上键
boolean right = fase; //向右键

public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
switch(key){
case :KeyEvent.VK_UP:
up = true;
break;
case :KeyEvent.VK_RIGHT:
right = true;
break;
}
if( up && right){
System.out.println("你按了向上键和向右键");
}
}

public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
switch(key){
case :KeyEvent.VK_UP:
up = false;
break;
case :KeyEvent.VK_RIGHT:
right = false;
break;
}

}

Answer 4

键盘同时只发送一个键，你每次获得的是一个键码，不是两个~~~~~