Java Swing 在运行时添加/删除 jButtons

2022-01-21 00:00:00 components java swing

我的应用程序有一个模块，它允许用户在运行时在 jLayeredpane 上添加 jButtons.我想向这个动态添加的内容添加动作侦听器，并且我必须提供在运行时删除动态添加的按钮的访问权限.有没有办法做到这一点?

My application has a module which allows the user to add jButtons on the jLayeredpane during runtime. I want to add action listeners to this dynamically added contents and also i have to provide access to delete the dynamically added buttons during runtime. Is there any way to do this ?

private Map<String, JButton> dynamicButtons;

public void addButton(String name) {
    JButton b = new JButton(name);
    b.addActionListener(new java.awt.event.ActionListener() {

        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    jLayeredPane2.add(b);
    dynamicButtons.put(name, b);
    jLayeredPane2.invalidate();
}

public void removeButton(String name) {
    JButton b = dynamicButtons.remove(name);
    jLayeredPane2.remove(b);
    jLayeredPane2.invalidate();
}

推荐答案

原始答案 总体上不错，但在这种情况下做得不同

为了跟踪任意数量的添加 JButtons，您需要将它们保存在一个列表中.

In order to keep track of an arbitrary number of added JButtons, you will need to keep them in a list.

因此，在您创建一个新按钮、为其添加侦听器并将其添加到窗格后，您需要将该新按钮保存在一个列表中.

So, after you create a new button, add the listeners to it, and add it to the pane, you then need to save that new button in a list.

这样您就可以跟踪您添加的所有按钮.

That way you can keep track of all of the buttons you have added.

您还可以使用 Map 将按钮名称映射到按钮.

You could also use a Map<String, JButton> that maps a button name to the button.

例子:

private Map<String, JButton> dynamicButtons;

public void addButton(String name) {
    JButton b = new JButton(name);
    b.addActionListener(someAction);
    yourPanel.add(b);
    dynamicButtons.put(name, b);
    yourPanel.invalidate();
}

public void removeButton(String name) {
    Button b = dynamicButtons.remove(name);
    yourPanel.remove(b);
    yourPanel.invalidate();
}

<小时>

以下是一个完整的类，可让您动态添加和删除按钮.这不完全是你想要的，但它应该让你真正接近.

The following is a full class that lets you add and remove buttons dynamically. It's not exactly what you want, but it should get you really close.

您的具体案例的代码:

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public class ExampleFrame extends JFrame {

    private JButton add, remove;
    private JPanel dynamicButtonPane, addRemovePane;

    private boolean waitingForLocationClick;

    public ExampleFrame() {
        super("Dynamic button example");
        waitingForLocationClick = false;
        add = new JButton("Add Button");
        add.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                addButton(JOptionPane
                        .showInputDialog("Name of the new button:"));
            }
        });
        remove = new JButton("Remove Button");
        remove.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                lookingToRemove = true;
            }
        });
        JPanel mainPane = new JPanel(new BorderLayout());
        dynamicButtonPane = new JPanel();
        dynamicButtonPane.setLayout(null);
        dynamicButtonPane.setPreferredSize(new Dimension(300, 300));
        addRemovePane = new JPanel();
        addRemovePane.add(add);
        addRemovePane.add(remove);
        mainPane.add(dynamicButtonPane, BorderLayout.NORTH);
        mainPane.add(addRemovePane, BorderLayout.SOUTH);
        add(mainPane);
        pack();
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        dynamicButtonPane.addMouseListener(pointSelectorListener);
    }

    private JButton buttonToPlace;

    public void addButton(String name) {
        JButton b = new JButton(name);
        b.setActionCommand(name);
        b.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (lookingToRemove) {
                    if (e.getSource() instanceof JButton) {
                        dynamicButtonPane.remove((Component) e.getSource());
                        dynamicButtonPane.validate();
                        dynamicButtonPane.repaint();
                    }
                } else
                    JOptionPane.showMessageDialog(ExampleFrame.this, "This is " + e.getActionCommand());
            }
        });
        waitingForLocationClick = true;
        lookingToRemove = false;
        buttonToPlace = b;
    }

    public void putButtonAtPoint(Point p) {
        System.out.println("Placing a button at: " + p.toString());
        dynamicButtonPane.add(buttonToPlace);
        buttonToPlace.setBounds(new Rectangle(p, buttonToPlace
                .getPreferredSize()));
        dynamicButtonPane.validate();
        buttonToPlace = null;
        waitingForLocationClick = false;
    }

    private boolean lookingToRemove = false;

    private final MouseListener pointSelectorListener = new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
            if (waitingForLocationClick) {
                putButtonAtPoint(e.getPoint());
            } else {
                System.out.println("Not in waiting state");
            }
        }
    };

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

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