Java 删除特定按钮

Delete a specific button

提问by Gon?alo Reino da Costa

I have a JPanel in a JFrame that contains 5 buttons. In another JPanel there is a button called "delete button", what I want to do is to click this button and than choose what button of the other 5 to delete by ckicking in one of them. Can anyone help me?

我在包含 5 个按钮的 JFrame 中有一个 JPanel。在另一个 JPanel 中，有一个名为“删除按钮”的按钮，我想要做的是单击此按钮，然后通过单击其中一个来选择要删除的其他 5 个按钮。谁能帮我？

    public class gui extends JFrame implements ActionListener
    {
      JPanel p1 = new JPanel();
      JPanel p2 = new JPanel();
      JPanel p2 = new JPanel();

      JButton b1 = new JButton("Delete");
      JButton b2 = new JButton("A");
      JButton b3 = new JButton("B");
      JButton b4 = new JButton("C");

      gui()
      {
        p1.setLayout(new GridLayout(1,2));
        p1.add(p2);
        p1.add(p3);

        p2.setLayout(new GridLayout(3,1));
        p2.add(b2);
        p2.add(b3);
        p2.add(b4);
        p3.add(b1);

        b1.addActionListener(this);
        b2.addActionListener(this);
        b3.addActionListener(this);
        b4.addActionListener(this);

      }

     public void actionPerformed(ActionEvent e)
     {
       if (e.getSource() == b1)
         // When I click this button I want to be able to delete a button of my choice (one of the other 3)
     }
   }

回答by aioobe

Here's a snippet of code to kick you off in the right direction:

这是一段代码，可以让您朝着正确的方向前进：

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

public class FrameTestBase extends JFrame {

    public static void main(String args[]) {
        FrameTestBase t = new FrameTestBase();

        final JPanel p = new JPanel();

        final JButton button = new JButton();

        button.setAction(new AbstractAction("Remove me!") {
            @Override
            public void actionPerformed(ActionEvent e) {
                p.remove(button);
                p.revalidate();
                p.repaint();
            }
        });

        p.add(button);
        t.setContentPane(p);

        t.setDefaultCloseOperation(EXIT_ON_CLOSE);
        t.setSize(400, 400);
        t.setVisible(true);
    }
}

Before click:

点击前：

After click:

点击后：

---

---

From the comments:

来自评论：

To generalize this, you could create an AbstractAction that takes the to-be-deleted button as argument. Use this AbstractAction, and update it as necessary whenever your delete-policy should change.

为了概括这一点，您可以创建一个将要删除的按钮作为参数的 AbstractAction。使用此 AbstractAction，并在您的删除策略发生变化时根据需要更新它。

回答by Edwin Buck

Use a chain of responsibility in the button listeners. One Button listener that listens for the "to be deleted" buttons and the "delete" button. Under normal operation this button listener just sends the "to be deleted" button events to the existing button events, but when it hears a "delete" button event, it then captures the "next" button event without sending it to the existing button listener, and acts to remove the button.

在按钮侦听器中使用责任链。一个 Button 侦听器，用于侦听“待删除”按钮和“删除”按钮。在正常操作下，这个按钮监听器只是将“待删除”按钮事件发送给现有按钮事件，但是当它听到“删除”按钮事件时，它会捕获“下一步”按钮事件而不将其发送给现有按钮监听器, 并用于移除按钮。

Ok you provided some code. Here is a solution that uses a chain of responsibility. Basically, if one ActionListener can't handle the event, it sends it to the next one, and so on.

好的，您提供了一些代码。这是一个使用责任链的解决方案。基本上，如果一个 ActionListener 无法处理该事件，它会将其发送给下一个，依此类推。

import java.awt.GridLayou;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.WindowConstants;

public class Gui extends JFrame {

  public static final long serialVersionUID = 1L;

  JPanel p1 = new JPanel();
  JPanel p2 = new JPanel();
  JPanel p3 = new JPanel();

  JButton b1 = new JButton("Delete");
  JButton b2 = new JButton("A");
  JButton b3 = new JButton("B");
  JButton b4 = new JButton("C");

  public Gui() {

    setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    p1.setLayout(new GridLayout(1, 2));
    p1.add(p2);
    p2.add(p3);

    p2.setLayout(new GridLayout(3, 1));
    p2.add(b2);
    p2.add(b3);
    p2.add(b4);

    p3.add(b1);

    DoItListener doIt = new DoItListener(null);
    DeleteItListener deleteIt = new DeleteItListener(this, doIt);

    b1.addActionListener(deleteIt);
    b2.addActionListener(deleteIt);
    b3.addActionListener(deleteIt);
    b4.addActionListener(deleteIt);

    add(p1);
    pack();
  }

  public void deleteButton(String name) {
    if (b2 != null && "A".equals(name)) {
      p2.remove(b2);
      b2 = null;
      p2.invalidate();
      p2.redraw();
    }
    if (b3 != null && "B".equals(name)) {
      p2.remove(b3);
      b3 = null;
      p2.invalidate();
      p2.redraw();
    }
    if (b4 != null && "A".equals(name)) {
      p2.remove(b4);
      b4 = null;
      p2.invalidate();
      p2.redraw();
    }
  }

  public static void main(String[] args) {
    java.awt.EventQueue.invokeLater(new Runnable() {
      public void run() {
        new Gui().setVisible(true);
      }
    });
  }
}

class DoItListener implements ActionListener {

  private ActionListener delegate;

  public DoItListener(ActionListener next) {
    delegate = next;
  }

  public void actionPerformed(ActionEvent e) {
    if (!("Delete".equals(e.getActionCommand()))) {
      System.out.println("doing " + e.getActionCommand());
    } else if (delegate != null) {
      delegate.actionPerformed(e);
    }
  }
}

class DeleteItListener implements ActionListener {

  private Gui gui;

  private boolean deleteNext;

  private ActionListener delegate;

  public DeleteItListener(Gui container, ActionListener next) {
    gui = container;
    delegate = next;
    deleteNext = false;
  }

  public void actionPerformed(ActionEvent e) {
    if ("Delete".equals(e.getActionCommand())) {
      deleteNext = true;
    } else if (deleteNext) {
      gui.deleteButton(e.getActionCommand());
      deleteNext = false;
    } else if (delegate != null) {
      delegate.actionPerformed(e);
    }
  }
}

回答by Dilum Ranatunga

Have a look at the glass pane. This tutorialshows how it is used.

看看玻璃板。本教程展示了它的使用方法。

At a high level, clicking the 'Delete' button would put the glass pane listener into a state where it:

在较高级别上，单击“删除”按钮会将玻璃窗格侦听器置于以下状态：

1. detects a click,
2. determines the target component,
3. determines whether the component is allowed to be deleted
4. and if so, delete the component.

1. 检测到点击，
2. 确定目标组件，
3. 确定是否允许删除组件
4. 如果是，请删除该组件。

As a design note, I would keep a Setof controls that are allowed to be deleted, and thereby separate the concerns. So when you add a button that is allowed to be deleted, it is your responsibility to also add it to the delete candidates set.

作为设计说明，我会保留Set一些允许删除的控件，从而将关注点分开。因此，当您添加允许删除的按钮时，您也有责任将其添加到删除候选集中。

回答by nIcE cOw

Here try this code out :

在这里试试这个代码：

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

public class DeleteButtonExample extends JFrame
{
    private boolean deleteNow = false;
    private JButton deleteButton;
    private JPanel leftPanel;
    private JPanel rightPanel;
    private JButton[] buttons = new JButton[5];

    private ActionListener deleteAction = new ActionListener()
    {
        public void actionPerformed(ActionEvent ae)
        {
            JButton button = (JButton) ae.getSource();
            if (deleteNow)
            {
                leftPanel.remove(button);
                leftPanel.revalidate();
                leftPanel.repaint();
                deleteNow = false;
            }
            else
            {
                // Do your normal Event Handling here.
                System.out.println("My COMMAND IS : " + button.getActionCommand());
            }
        }
    };

    private void createAndDisplayGUI()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationByPlatform(true);
        setLayout(new GridLayout(0, 2));

        leftPanel = new JPanel();
        leftPanel.setLayout(new GridLayout(0, 2));
        leftPanel.setBackground(Color.WHITE);
        for (int i = 0; i < 5; i++)
        {
            buttons[i] = new JButton("" + i);
            buttons[i].addActionListener(deleteAction);
            buttons[i].setActionCommand("" + i);
            leftPanel.add(buttons[i]);
        }

        rightPanel = new JPanel();
        rightPanel.setBackground(Color.BLUE);

        JButton deleteButton = new JButton("DELETE");
        deleteButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                JOptionPane.showMessageDialog(null, "Delete any Button from the Left Panel by clicking it."
                                                                                    , "INFO : ", JOptionPane.INFORMATION_MESSAGE);
                deleteNow = true;                                                                   
            }
        });
        rightPanel.add(deleteButton);

        add(leftPanel);
        add(rightPanel);
        pack();
        setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new DeleteButtonExample().createAndDisplayGUI();
            }
        });
    }
}

OUTPUT :

输出 ：

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