Java Swing在运行时添加/删除jButton

• Z时代
• 2024-01-10
• 分类：问答

我的应用程序有一个模块，允许用户在运行时在jLayeredpane上添加jButton。我想向此动态添加的内容添加动作侦听器，而且我还必须提供在运行时删除动态添加的按钮的访问权限。有什么办法吗？

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();
}

回答：

总体上不错，但是在这种情况下做的却不同

为了跟踪添加的任意数量JButtons，您需要将它们保留在列表中。

因此，在创建新按钮之后，将侦听器添加到该按钮，然后将其添加到窗格中，然后需要将该新按钮保存在列表中。

这样，您可以跟踪已添加的所有按钮。

您还可以使用Map<String, JButton>将按钮名称映射到按钮的。

例：

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();
}

以下是一个完整的类，可让您动态添加和删除按钮。这并不是您想要的，但它应该可以使您真正接近。

特定情况的代码：

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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