Question

对于我的程序，只要用户添加按钮，该按钮就会添加到“panel1”和“panel2”。到目前为止，我可以删除用户在第一个JPanel，panel1中所需的按钮。但是如何根据我在下面提供的代码删除第二个JPanel中的相同按钮？我应该检查第二个面板是否包含具有相同名称的按钮？我该怎么做？

public class deleteButton
{
   public boolean deleteNow = false;

   class ClickListener implements ActionListener
   {
       public void actionPerformed(ActionEvent e)
       {
            deleteNow = true;
       }
   }
   ActionListener deleteButtonClicked = new ClickListener();
   deleteButton.addActionListener(deleteButtonClicked);

   class ClickListenerTwo implements ActionListener
   {
       public void actionPerformed(ActionEvent f)
       {
           JButton buttonThatWasClicked = (JButton) e.getSource();
           if (deleteNow == true)
           {

               panel1.remove(buttonThatWasClicked);
               panel1.revalidate();
               panel1.repaint();
               //This is where I want it to delete from panel2.

               deleteNow = false;  
           }
           else
           { 
               System.out.println("The button wasn't deleted");
           }
       } 
   }

}

Answer 1

您可以遍历组件树以查找按钮。像这样的东西

/**
 * Searches for all children of the given component which are instances of the given class.
 *
 * @param aRoot start object for search.
 * @param aClass class to search.
 * @param <E> class of component.
 * @return list of all children of the given component which are instances of the given class. Never null.
 */
public static <E> List<E> getAllChildrenOfClass(Container aRoot, Class<E> aClass) {
    final List<E> result = new ArrayList<E>();
    final Component[] children = aRoot.getComponents();
    for (final Component c : children) {
        if (aClass.isInstance(c)) {
            result.add(aClass.cast(c));
        }
        if (c instanceof Container) {
            result.addAll(getAllChildrenOfClass((Container) c, aClass));
        }
    }
    return result;
}

/** 
 * Finds the button by its text.
 * @param aParent container for button search.
 * @param aText text of button.
 * @return button with the given text or null if no such button found.
 */
public static JButton findButtonByText(Container aParent, String aText) {
    List<JButton> buttons = getAllChildrenOfClass(aParent, JButton.class);
    for (JButton btn : buttons) {
        if (btn.getText().equals(aText)) {
           return btn;
        }
    }
    return null;
}

用法：

JButton btn = findButtonByText(panel2, buttonThatWasClicked.getText());
if (btn != null && btn.getParent() != null) {
   btn.getParent().remove(btn);
}

Answer 2

从JPanel删除组件的代码没有问题。也许代码的其他部分可能存在其他问题，但下面的代码可以正常工作，您可以检查逻辑并编辑代码：

public class DeleteButton extends JFrame {
    private boolean flag;

    public DeleteButton() {
        setSize(new Dimension(400, 400));
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        JPanel panel = new JPanel();
        getContentPane().add(panel);

        JButton button1 = new JButton("Set Flag");
        panel.setLayout(new FlowLayout());
        panel.add(button1);
        JButton button2 = new JButton("Delete");
        panel.add(button2);

        button1.addActionListener(e -> flag = true);
        button2.addActionListener(e -> {
            JButton buttonThatWasClicked = (JButton) e.getSource();
            if (flag) {
                panel.remove(buttonThatWasClicked);
                panel.revalidate();
                panel.repaint();
                flag = false;
            } else {
                System.out.println("The button wasn't deleted");
            }
        });
        setVisible(true);
    }
    public static void main(String[] args) {
        new DeleteButton();
    }
}

如何删除另一个JPanel中的相同按钮？

2 个答案: