Question

我在java中编写了一个基本的控制板gui。按下箭头键时，文本将显示键盘上按下的按钮，按钮将改变颜色。

问题是这个程序在windows中工作正常，但是当我在我的覆盆子pi上运行一个名为raspbian的linux版本时，这似乎不起作用。当我按下按钮时，程序没有做任何事情。

package finalRobotControl;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.xml.bind.Marshaller.Listener;

public class Main implements KeyListener{
    public static JButton buttonLeft;
    public static JButton buttonRight;
    public static JButton buttonUp;
    public static JButton buttonDown;
    public static JLabel stage;

    public static void main(String [] args){
        JFrame window = new JFrame("RobotController");
        window.setVisible(true);
        window.setSize(200, 200);
        window.setPreferredSize(new Dimension(400, 200));
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        panel.setLayout(null);

        //add panel to window
        window.add(panel);

        stage = new JLabel("");
        stage.setBounds(85, 65, 50, 35);
        panel.add(stage);

        buttonLeft = new JButton("←");
        buttonLeft.setBounds(10, 65, 50, 35);
        //buttonLeft.setBackground(Color.BLUE);
        panel.add(buttonLeft);

        buttonRight = new JButton("→");
        buttonRight.setBounds(130, 65, 50, 35);
        panel.add(buttonRight);


        buttonUp = new JButton("↑");
        buttonUp.setBounds(70, 25, 50, 35);
        panel.add(buttonUp);

        buttonDown = new JButton("↓");
        buttonDown.setBounds(70, 105, 50, 35);
        panel.add(buttonDown);

        window.addKeyListener(new Main());

    }

    @Override
    public void keyPressed(KeyEvent e) {
        // TODO Auto-generated method stub
        if(e.getKeyCode() == KeyEvent.VK_LEFT){
            buttonLeft.setBackground(Color.WHITE);
            System.out.println("Left");
            stage.setText("Left");
        }
        if(e.getKeyCode() == KeyEvent.VK_RIGHT){
            buttonRight.setBackground(Color.WHITE);
            System.out.println("Right");
            stage.setText("Right");
        }
        if(e.getKeyCode() == KeyEvent.VK_UP){
            buttonUp.setBackground(Color.WHITE);
            System.out.println("Up");
            stage.setText("Up");
        }
        if(e.getKeyCode() == KeyEvent.VK_DOWN){
            buttonDown.setBackground(Color.WHITE);
            System.out.println("Down");
            stage.setText("Down");
        }
    }  

    @Override
    public void keyReleased(KeyEvent e) {
        // TODO Auto-generated method stub
        JButton lol = new JButton();
        if(e.getKeyCode() == KeyEvent.VK_LEFT){
            buttonLeft.setBackground(lol.getBackground());
            stage.setText("");
        }
        if(e.getKeyCode() == KeyEvent.VK_RIGHT){
            buttonRight.setBackground(lol.getBackground());
            stage.setText("");
        }
        if(e.getKeyCode() == KeyEvent.VK_UP){
            buttonUp.setBackground(lol.getBackground());
            stage.setText("");
        }
        if(e.getKeyCode() == KeyEvent.VK_DOWN){
            buttonDown.setBackground(lol.getBackground());
            stage.setText("");
        }




    }

    @Override
    public void keyTyped(KeyEvent arg0) {
        // TODO Auto-generated method stub

    }

}

Answer 1

KeyListener众所周知，因为它会产生KeyEvent时的挑剔。 KeyListener只会在注册到IS的组件可调焦并且HAS焦点时生成KeyEvent。

将KeyListener直接添加到窗口会使其变得更加困难，因为窗口和使用之间可能存在任意数量的组件，这可能会导致焦点化。

相反，你应该使用Key Bindings API，它允许你控制生成关键事件所需的焦点水平

使用keylisteners的Java swing gui程序在linux中不起作用

1 个答案: