按下键盘键时如何改变焦点在不同的Jbutton上？

Question

So hey guys, I've been trying to design a piano through java, net-beans for my final project at uni. thing here is every thing works well so far but I've got issues with focus here. for example I'm trying to play the keys through the keyboard, i want the piano keys to get focused to the specified key its assigned any idea on how to do it? much appreciated. this is my 1st question here, so I'm not sure if I'm asking the right things here.

I'm gonna provide the sample I'm working with.

   package javaapplication5;

   import sun.audio.*;

   import java.io.*;

   import javax.swing.JOptionPane;

   public class NewJFrame1 extends javax.swing.JFrame {

public NewJFrame1() {

    initComponents();

}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jButton1 = new javax.swing.JButton();
    jButton2 = new javax.swing.JButton();
    jButton3 = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jButton1.setText("A");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });
    jButton1.addFocusListener(new java.awt.event.FocusAdapter() {
        public void focusGained(java.awt.event.FocusEvent evt) {
            jButton1FocusGained(evt);
        }
    });
    jButton1.addKeyListener(new java.awt.event.KeyAdapter() {
        public void keyPressed(java.awt.event.KeyEvent evt) {
            jButton1KeyPressed(evt);
        }
        public void keyReleased(java.awt.event.KeyEvent evt) {
            jButton1KeyReleased(evt);
        }
    });

    jButton2.setText("B");
    jButton2.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton2ActionPerformed(evt);
        }
    });
    jButton2.addKeyListener(new java.awt.event.KeyAdapter() {
        public void keyPressed(java.awt.event.KeyEvent evt) {
            jButton2KeyPressed(evt);
        }
    });

    jButton3.setText("C");
    jButton3.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton3ActionPerformed(evt);
        }
    });
    jButton3.addKeyListener(new java.awt.event.KeyAdapter() {
        public void keyPressed(java.awt.event.KeyEvent evt) {
            jButton3KeyPressed(evt);
        }
    });

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addGap(89, 89, 89)
            .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 59, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(18, 18, 18)
            .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(18, 18, 18)
            .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(123, Short.MAX_VALUE))
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
            .addContainerGap(91, Short.MAX_VALUE)
            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 111, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 106, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 105, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(110, 110, 110))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(45, 45, 45)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(190, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(51, Short.MAX_VALUE))
    );

    pack();
}// </editor-fold>

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         

    InputStream iAudio;

    try{
        iAudio = new FileInputStream(new File("C:\\Users\\MohammedRishad\\Desktop\\Audios\\A.wav"));
        AudioStream iMusic = new AudioStream(iAudio);
        AudioPlayer.player.start(iMusic);
    }
    catch(Exception e){
        JOptionPane.showMessageDialog(null, e);
    }
}                                        

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    InputStream iAudio;

    try{
        iAudio = new FileInputStream(new File("C:\\Users\\MohammedRishad\\Desktop\\Audios\\B.wav"));
        AudioStream iMusic = new AudioStream(iAudio);
        AudioPlayer.player.start(iMusic);
    }
    catch(Exception e){
        JOptionPane.showMessageDialog(null, e);
    }
}                                        

private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
   InputStream iAudio;

    try{
        iAudio = new FileInputStream(new File("C:\\Users\\MohammedRishad\\Desktop\\Audios\\C.wav"));
        AudioStream iMusic = new AudioStream(iAudio);
        AudioPlayer.player.start(iMusic);
    }
    catch(Exception e){
        JOptionPane.showMessageDialog(null, e);
    }
}                                        

private void jButton1KeyPressed(java.awt.event.KeyEvent evt) {                                    

    if(evt.getKeyChar()=='z'){
    InputStream iAudio;

    try{
        iAudio = new FileInputStream(new File("C:\\Users\\MohammedRishad\\Desktop\\Audios\\A.wav"));
        AudioStream iMusic = new AudioStream(iAudio);
        AudioPlayer.player.start(iMusic);
    }
    catch(Exception e){
        JOptionPane.showMessageDialog(null, e);
    }
   }

}                                   

private void jButton2KeyPressed(java.awt.event.KeyEvent evt) {                                    

    if(evt.getKeyChar()=='x'){
    InputStream iAudio;

    try{
        iAudio = new FileInputStream(new File("C:\\Users\\MohammedRishad\\Desktop\\Audios\\B.wav"));
        AudioStream iMusic = new AudioStream(iAudio);
        AudioPlayer.player.start(iMusic);
    }
    catch(Exception e){
        JOptionPane.showMessageDialog(null, e);
    }
   }
}                                   

private void jButton3KeyPressed(java.awt.event.KeyEvent evt) {                                    

    if(evt.getKeyChar()=='c'){
    InputStream iAudio;

    try{
        iAudio = new FileInputStream(new File("C:\\Users\\MohammedRishad\\Desktop\\Audios\\C.wav"));
        AudioStream iMusic = new AudioStream(iAudio);
        AudioPlayer.player.start(iMusic);
    }
    catch(Exception e){
        JOptionPane.showMessageDialog(null, e);
    }
   }
}                                   

public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {

        public void run() {
            new NewJFrame1().setVisible(true);
        }
    });
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JPanel jPanel1;
// End of variables declaration

}

As this is a sample I'm working with just 3 buttons here. I'd like to get all the help i can thanks in advance

Answer 1

Register keylister with jframe using addKeyListener(...) for all three keys. so when any keypressed within frame, key event works. Before key press, check your frame is active. if not click within frame then press key. Can also change focus on button using requestFocus() method

Answer 2

可以使用requestFocus（）方法更改按钮的焦点