Question

我在一个框架中有一堆标签，基本上用作显示文本的多行输出。在程序的某些点上，用户需要从给定的选项中选择一个选项。他们执行此操作的方法是单击相应的JLabel。

我尝试使用JLabel数组，但是功能不起作用。然后，我为每个JLabel制作了一个单独的ActionEvent，但是可以运行，但是是否有一个优雅或有效的代码？

Answer 1

不客气。

您描述了您的问题，我认为我可以照做。

您可以找出ActionListener的相似之处，并将这些相似之处放入super-Class

对我来说，另一种可能性似乎是“多合一” ActionListener。其actionPerformed-方法的参数为ActionEvent。此ActionEvent提供了一种getSource()方法，您可以检索发生在JComponent上的ActionEvent。因此，如果您为JLabel指定名称，则可以在actionPerformed-方法

中检查名称

修改

像这样：

public void actionPerformed(final ActionEvent actionEvent) {
    final String name = ((JComponent) actionEvent.getSource()).getName();
    switch (name) {
        case "label1":
            handleLabel1();
            break;
        case "label2":
            handleLabel2();
            break;
        case "label3":
            handleLabel3();
            break;
        default:
            break;
    }
}

编辑1

import java.awt.AWTEvent;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;

public class Application extends JFrame {
    private abstract class MyComponentListener implements MouseListener, ActionListener {
        protected void actionOnButton(final AWTEvent e) {
            final JButton button = (JButton) e.getSource();
            switch (button.getName()) {
                case "button1":
                    System.out.println("Hello World");
                    break;
                default:
                    System.out.println("mouse button one clicked on " + button.getName());
                    break;
            }
            // more general
            this.actionOnComponent(e);
        }

        protected void actionOnComponent(final AWTEvent e) {
            final JComponent component = (JComponent) e.getSource();
            final int index = Integer.valueOf(component.getName().replaceAll("[^0-9]", "")).intValue();
            switch (index) {
                case 1:
                    System.out.println("Hello World");
                    break;
                default:
                    System.out.println("mouse button one clicked on " + component.getName());
                    break;
            }
        }

        protected void actionOnLabel(final AWTEvent e) {
            final JLabel label = (JLabel) e.getSource();
            switch (label.getName()) {
                case "label1":
                    System.out.println("Hello World");
                    break;
                default:
                    System.out.println("mouse button one clicked on " + label.getName());
                    break;
            }
            // more general
            this.actionOnComponent(e);
        }
    }

    private class MyListener extends MyComponentListener {
        /**
         * {@link ActionListener#actionPerformed(ActionEvent)}
         */
        @Override
        public void actionPerformed(final ActionEvent e) {
            System.out.println("next line(s) generated by ActionListener");
            this.actionOnButton(e);
        }

        @Override
        public void mouseClicked(final MouseEvent e) {
            // whole process of mouse button down and up
            if ((e.getButton() == 1)) {
                System.out.println("next line(s) generated by MouseListener");
                if ((e.getSource() instanceof JLabel)) {
                    this.actionOnLabel(e);
                } else if (e.getSource() instanceof JButton) {
                    this.actionOnButton(e);
                }
            }
        }

        @Override
        public void mouseEntered(final MouseEvent e) {
            // on mouse over
        }

        @Override
        public void mouseExited(final MouseEvent e) {
            // on mouse out
        }

        @Override
        public void mousePressed(final MouseEvent e) {
            // mouse button down
        }

        @Override
        public void mouseReleased(final MouseEvent e) {
            // mouse button up after down
        }
    }

    private static final long serialVersionUID = 1L;

    private Application() {
        super();
    }

    public void start() {
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.getContentPane().setLayout(new BoxLayout(this.getContentPane(), BoxLayout.PAGE_AXIS));
        this.addLabel("Hello World - Label", "label1");
        this.addLabel("Label 2", "label2");
        this.addLabel("Label 3", "label3");
        this.addButton("Hello Word - Button", "button1");
        this.addButton("Button 2", "button2");
        final Dimension dimension = new Dimension(500, 150);
        this.setSize(dimension);
        this.setPreferredSize(dimension);
        this.setVisible(true);
    }

    private void addButton(final String text, final String name) {
        final JButton button = new JButton(text);
        button.setName(name);
        button.addMouseListener(new MyListener());
        button.addActionListener(new MyListener());
        this.getContentPane().add(button);
    }

    private void addLabel(final String text, final String name) {
        final JLabel label = new JLabel(text);
        label.setName(name);
        label.addMouseListener(new MyListener());
        this.getContentPane().add(label);
    }

    public static void main(final String[] args) {
        final Application app = new Application();
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                app.start();
            }
        });
    }
}

较小的程序，可从多个jLabel获取鼠标的单击输入

1 个答案: