main 的 JPanel 没有从另一个类更新

Question

我有扩展 JFrame 的 Home 类，它包含一个静态变量 panel_event。我有另一个名为EventLabel 的类，它创建了一个标签及其功能，并使用refresh() 方法将其添加到面板中，代码运行没有错误，但我的panel_event 内容没有得到更新“显示”

我已经添加了revalidate()和repaint()方法

public EventLabel(String name2, String date2, int priority2, String note2) {
    super();
    this.name = name2;
    this.date = date2;
    this.priority = priority2;
    this.note = note2;
}

public void buildLabel() {
    label = new JLabel(this.getName());
    label.setBounds(10, 11, 403, 34);
    label.setForeground(Color.WHITE);
    label.setFont(new Font("Yu Gothic UI Light", Font.PLAIN, 20));
    String n = this.getNote();
    String d = this.getDate();
    int p = this.getPriority();
    String na = this.getName();
    setFont(new Font("Yu Gothic UI Light", Font.PLAIN, 20));
    label.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
            EventDetailFrame detailFrame = new EventDetailFrame();
            detailFrame.NewWindow();
            detailFrame.textAreaNoteD.setText(n);
            detailFrame.textFieldNameD.setText(na);
            detailFrame.textFieldDateD.setText(d);
            detailFrame.textFieldPriorityD.setText("Priority");
        }
    });
}

public void refresh(){
    panel_event.add(label);
    panel_event.revalidate();
    panel_event.repaint();
}

这是带有按钮的框架，假设更改panel_event的内容

btnSaveAndClose.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {            
        String name = txtEventName.getText();
        String date = txtEventDate.getText();
        String note = txtEventNote.getText();
        int priority = getPriorityNumber(txtEventPriority.getText());
        Event event = new Event(name, date, note, priority);
        EventLabel event_label = new EventLabel(event.getName(),event.getDate(),event.getPriority(),event.getNote());
        event_label.buildLabel();
        event_label.refresh();
        dispose();
    }
});

点击btnSaveAndClose后，我预计panel_event会显示我的新JLabel

Answer 1

我创建了一个关于如何显示新标签的工作示例。您可以调用 validate() 和 repaint()。

import java.awt.Color;
import java.awt.Font;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.StringJoiner;
import javax.swing.BorderFactory;
import javax.swing.JLabel;
import javax.swing.JOptionPane;

public class EventLabel extends JLabel
{
    private static final long serialVersionUID = -3122247523298894551L;

    public EventLabel(String name, String date, String priority, String note)
    {
        super(name);
        setBorder(BorderFactory.createLineBorder(Color.WHITE, 3, false));
        setFont(new Font("Yu Gothic UI Light", Font.PLAIN, 20));
        this.setOpaque(true);
        setBackground(Color.WHITE);
        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e)
            {
                StringJoiner text = new StringJoiner("\n");
                text.add("name: " + name);
                text.add("date: " + date);
                text.add("priority: " + priority);
                text.add("note: " + note);
                JOptionPane.showMessageDialog(null, text, "Event", JOptionPane.INFORMATION_MESSAGE);
            }
        });
    }
}

与

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class Main
{
    private static JButton button;
    private static JPanel labelPanel;
    private static JTextField nameField;
    private static JTextField dateField;
    private static JTextField priorityField;
    private static JTextField noteField;

    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run()
            {
                JFrame window = new JFrame();
                window.setResizable(false);
                window.setTitle("Label Test");
                window.getContentPane().add(getContent());
                initController();
                window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                window.setSize(680, 700);
                window.setLocationRelativeTo(null);
                window.setVisible(true);
            }
        });
    }

    protected static void initController()
    {
        button.addActionListener(event -> {
            labelPanel.add(new EventLabel(nameField.getText(), dateField.getText(), priorityField.getText(),
            noteField.getText()));
            nameField.setText("");
            dateField.setText("");
            priorityField.setText("");
            noteField.setText("");
            labelPanel.validate();
            labelPanel.repaint();
        });
    }

    private static Component getContent()
    {
        JPanel panel = new JPanel(new BorderLayout());
        panel.add(getNorthPanel(), BorderLayout.NORTH);
        labelPanel = new JPanel(new FlowLayout());
        labelPanel.setBorder(BorderFactory.createTitledBorder("Events"));
        panel.add(labelPanel, BorderLayout.CENTER);
        return panel;
    }

    private static Component getNorthPanel()
    {
        JPanel panel = new JPanel(new FlowLayout());
        JPanel inputPanel = new JPanel(new GridLayout(0, 2));
        inputPanel.setPreferredSize(new Dimension(400, 100));
        nameField = new JTextField();
        dateField = new JTextField();
        priorityField = new JTextField();
        noteField = new JTextField();
        inputPanel.add(new JLabel("name"));
        inputPanel.add(nameField);
        inputPanel.add(new JLabel("date"));
        inputPanel.add(dateField);
        inputPanel.add(new JLabel("priority"));
        inputPanel.add(priorityField);
        inputPanel.add(new JLabel("note"));
        inputPanel.add(noteField);
        panel.add(inputPanel);
        button = new JButton("add event");
        panel.add(button);
        return panel;
    }
}