Java的动作侦听器 [英] Java action listener

问题描述

我有4个名单排成列在我的程序的按钮。截至目前，我有4个回路，检查，看是否有按钮被按下。有没有一种简单的方法来检查是否有按钮被点击，而不是通过每个列表循环，看看是否被点击某个按钮。必须有检查了ActionSource == anybutton...

I have 4 lists of buttons arranged into column in my program. As of now I have 4 loops that check to see if a button has been clicked or not. Is there a simple way to check if any button has been clicked instead of looping through each list to see if that certain button was clicked. There must be an easier way to check if "actionSource == anybutton"...

推荐答案

使用匿名内部类为每个按钮：

Use anonymous inner classes for each button:

JButton button = new JButton("Do Something");
button.addActionListener( new ActionListener()
{
    public void actionPerformed(ActionEvent e)
    {
        System.out.println("Do Something Clicked");
    }
});

或者，如果你的逻辑是相关的，那么你就可以共享一个监听器：

Or if your logic is related, then you can share a listener:

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

public class ButtonCalculator extends JFrame implements ActionListener
{
    private JButton[] buttons;
    private JTextField display;

    public ButtonCalculator()
    {
        display = new JTextField();
        display.setEditable( false );
        display.setHorizontalAlignment(JTextField.RIGHT);

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout( new GridLayout(0, 5) );
        buttons = new JButton[10];

        for (int i = 0; i < buttons.length; i++)
        {
            String text = String.valueOf(i);
            JButton button = new JButton( text );
            button.addActionListener( this );
            button.setMnemonic( text.charAt(0) );
            buttons[i] = button;
            buttonPanel.add( button );
        }

        getContentPane().add(display, BorderLayout.NORTH);
        getContentPane().add(buttonPanel, BorderLayout.SOUTH);
        setResizable( false );
    }

    public void actionPerformed(ActionEvent e)
    {
        JButton source = (JButton)e.getSource();
        display.replaceSelection( source.getActionCommand() );
    }

    public static void main(String[] args)
    {
        UIManager.put("Button.margin", new Insets(10, 10, 10, 10) );
        ButtonCalculator frame = new ButtonCalculator();
        frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible(true);
    }
}

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