Swing JButton事件

Question

I have JButton and want on event call this class method show() when this button in pressed. I know how to this, if I want use method from another class, but I need call method from same class as button.

JButton search = new JButton(new ButtonAction("Search", KeyEvent.VK_A));

I try add

JButton search = new JButton(show());

But it works only 1 time when object creating, but not when button is pressed.

Answer 1

If I understand you correctly, you want to call a method from the class that you created the button in rather than a method from another class.

First off, notice that while you are technically calling a method here

JButton search = new JButton(new ButtonAction("Search", KeyEvent.VK_A));

what is really going on is that you are passing a ButtonAction object to the JButton constructor. The closest thing that I can think of that will get what you want is having the class you are using extend ButtonAction.

Answer 2

Not sure what you want here... but if you want to attach an actionListener() to a JButton , you can do the following. Why do you need to listen to A ?

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class ActionListenerExample1 extends JFrame
        implements ActionListener, KeyListener {
    private static final long serialVersionUID = 1L;

    private JTextField searchText;
    private JButton searchButton1;
    private JButton searchButton2;

    public ActionListenerExample1() {
        initialize();

        this.pack();
        this.setLocationRelativeTo(null);
        this.setVisible(true);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    protected void initialize() {
        searchText = new JTextField(30);
        searchButton1 = new JButton("Search 1");
        searchButton2 = new JButton("Search 2");

        searchText.addKeyListener(this);
        searchButton1.addActionListener(this);
        searchButton2.addActionListener(new ButtonAction());

        this.setLayout(new FlowLayout());
        this.add(searchText);
        this.add(searchButton1);
        this.add(searchButton2);
    }

    public static void main(String[] args) {
        new ActionListenerExample1();
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == searchButton1) {
            buttonAction("GLOBAL LISTENER");
        }
    }

    private class ButtonAction implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent e) {
            buttonAction("LOCAL LISTENER");
        }
    }

    private void buttonAction(String label) {
        JOptionPane.showMessageDialog(this,
            String.format("%s: %s", label, searchText.getText()));
    }

    @Override
    public void keyPressed(KeyEvent e) {
        if (e.getKeyChar() == KeyEvent.VK_A) {
            buttonAction("KEYBOARD");
        }
    }

    @Override
    public void keyReleased(KeyEvent e) { }

    @Override
    public void keyTyped(KeyEvent e) { }
}