Question

我正在尝试在java中进行简单的反应测试。当屏幕变为绿色时我按空格键应该改变te boolean“点击进入false并停止测量时间的循环。实际上，关键列表器什么都不做。我是否将keay听众添加到正确的组合（jpanel面板）？还有其他问题吗？

    import java.awt.Color;
    import java.awt.RenderingHints.Key;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.awt.event.KeyEvent;
    import java.awt.event.KeyListener;        
    import javax.swing.*;

    public class mainCheck {
    // //////////////////////////////////////
    public static void timeKeeper() {
         boolean clicked=false;
        long time = 10000;
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        panel.setBackground(Color.GREEN);
        while (time > 0 && !clicked) {
            try {
                Thread.sleep(1);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            time--;
        }
        panel.setBackground(Color.gray);
        long time2= 10000-time;
        JLabel x = new JLabel("" +time2+"");
        panel.add(x);    
    }

    // //////////////////////////////////////
    static boolean clicked;
    JFrame frame;
    static JPanel panel;

    public mainCheck() {
        frame = new JFrame();
        panel = new JPanel();
        clicked = false;
        Handler handler = new Handler();
        frame.addKeyListener(handler);
        frame.add(panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(500,500);
        frame.setVisible(true);
    }
    // //////////////////////////////////////

    public static void main(String[] args) {
        mainCheck f = new mainCheck();
        panel.getActionMap();           
        f.timeKeeper();
    }

    // //////////////////////////////////////
    public class Handler implements KeyListener {

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

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

        @Override
        public void keyTyped(KeyEvent e) {
            // TODO Auto-generated method stub
            if (e.getKeyCode() == KeyEvent.VK_SPACE) {
                clicked = false;
                System.out.println("space pressed");
            }    
        }    
    }
}

Answer 1

不要使用Thread.sleep(5000);块Event Dispatch Thread，在睡眠期间，您可以将所有事件丢失到已经可见的Swing GUI
使用Swing Timer代替
Thread.sleep(1);可能适当延迟空间环境，非人类，非常短时间内攻击Native OS中的延迟（8-14毫秒，取决于原生OS）
JLabel x = new JLabel("" +time2+"");和panel.add(x);并非任何通知JComponents的某些部分被删除或添加，必须通知已使用的{{1}通过使用方法LayoutManager和JPanel，（FlowLayou在API中有revalidate t}，例如

repaint

应在Initial Thread
请勿使用KeyListener使用KeyBindings，否则您（焦点猎手）需要设置JLabel x = new JLabel("" +time2+""); panel.add(x); panel.revalidate(); panel.repaint();

Answer 2

问题是你“ e.getKeyCode（）”总是“ 0 ”所以更改“ e.getKeyChar（）”和“（char）32 ”
另一个问题在于您将 clicked = false 放在必须 “的真”

你遇到的最后一个问题是“ timeKeeper（）”你必须删除“布尔”，因为它已经被声明了

Bad public static void timeKeeper() { boolean clicked=false ....} Good public static void timeKeeper() { clicked=false ....}

这是正确的代码：

import java.awt.Color; import java.awt.event.*; import javax.swing.*; public class mainCheck { // ////////////////////////////////////// public static void timeKeeper() { clicked=false; long time = 10000; try { Thread.sleep(5000); } catch (InterruptedException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } panel.setBackground(Color.GREEN); while (time > 0 && !clicked) { try { Thread.sleep(1); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } time--; } panel.setBackground(Color.gray); long time2= 10000-time; JLabel x = new JLabel("" +time2+""); panel.add(x); } // ////////////////////////////////////// static boolean clicked; JFrame frame; static JPanel panel; Handler handler = new Handler(); public mainCheck() { frame = new JFrame(); panel = new JPanel(); clicked = false; frame.addKeyListener(handler); frame.add(panel); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(500,500); frame.setVisible(true); } // ////////////////////////////////////// public static void main(String[] args) { mainCheck f = new mainCheck(); panel.getActionMap(); f.timeKeeper(); } // ////////////////////////////////////// public class Handler implements KeyListener { @Override public void keyPressed(KeyEvent e) { // TODO Auto-generated method stub } @Override public void keyReleased(KeyEvent e) { // TODO Auto-generated method stub } @Override public void keyTyped(KeyEvent e) { if (e.getKeyChar() == (char)32) { clicked = true; System.out.println("space pressed"); } } } }

Answer 3

使用Thread.sleep（）减少时间值是一个非常糟糕的主意。改为使用Timer对象：

public void myTimer(){
    Timer myTimer = new Timer(delay, new ActionListener(){
        public void actionPerformed(ActionEvent e){
            //Stuff to do
        }
    });
}

其中delay是您延迟计时器的时间。使用myTimer.start（）;

启动计时器

遇到keyListener问题

3 个答案: