java - 为什么从其他 Jframe 中的另一个面板设置 Jframe 中的面板内容不起作用？

Question

我知道我以图形方式设计面板内容以及 jframe 中所有可能的方法，然后我在另一个 jframe 中使用该面板，我需要做的就是创建另一个框架的实例并获取它的面板并影响它到我当前 jframe 中的面板。

这是我尝试过的代码第一个包含我设计的面板模型的 jframe :

  package chemsou;

  import java.util.Hashtable;
  import javax.swing.JCheckBox;
  import javax.swing.JPanel;

  public class CheckListe extends javax.swing.JFrame {

   /**
    * Creates new form NewJFrame
    */
   Hashtable<String, JCheckBox> model = new Hashtable<>();
   public JPanel getPanel(){
      return jPanel1;
   }

   public CheckListe(String[] list) {
      initComponents();
      jPanel1.setLayout(new java.awt.GridLayout(0, 1, 0, 4));
      for (String element : list) {

          model.put(element, new JCheckBox(element));
          jPanel1.add(model.get(element));
      }

   }

   public CheckListe() {

       initComponents();

   }
  @SuppressWarnings("unchecked")
  // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

    jPanel1 = new javax.swing.JPanel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jPanel1.setLayout(new java.awt.GridLayout(0, 1, 0, 4));

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 93, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(0, 388, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, 535, Short.MAX_VALUE)
    );

    pack();
}// </editor-fold>                        

/**
 * @param args the command line arguments
 */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
       //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
       /* If Nimbus (introduced in Java SE 6) is not available, stay with the  default look and feel.
      * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
       */
       try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
               if ("Nimbus".equals(info.getName())) {
                  javax.swing.UIManager.setLookAndFeel(info.getClassName());
                  break;
               }
           }
       } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(CheckListe.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
           java.util.logging.Logger.getLogger(CheckListe.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
       } catch (IllegalAccessException ex) {
           java.util.logging.Logger.getLogger(CheckListe.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
          java.util.logging.Logger.getLogger(CheckListe.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
       }
       //</editor-fold>
       //</editor-fold>

       /* Create and display the form */
       java.awt.EventQueue.invokeLater(new Runnable() {
          public void run() {
               new CheckListe().setVisible(true);
          }
       });
   }

   // Variables declaration - do not modify                     
   private javax.swing.JPanel jPanel1;
   // End of variables declaration                   
}

我的 jframe，我在其中调用第一帧并将面板设置为建模的:

private void jRadioButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                              
    // TODO add your handling code here:
    String[] list =new String[]{"e1","e2","e3"};
    CheckListe checkListe = new CheckListe(list);
   // CheckListePanel.setLayout(checkListe.getPanel().getLayout());
    CheckListePanel = checkListe.getPanel();

    checkListe.setVisible( true );
    CheckListePanel.setVisible(true);
    CheckListePanel.setSize(100, 500);
    CheckListePanel.revalidate();
    CheckListePanel.repaint();
    System.out.println("done");
}                                             

当我运行代码时，我可以看到另一个 jframe 包含设计的面板，但调用者 jframe 不执行任何操作

我应该做什么？

Answer 1

1. 您没有对放入 CheckListePanel 变量中的 JPanel 对象执行任何操作，以允许其显示。
2. 您需要将该 JPanel 对象添加到顶级窗口中才能显示。
3. 此外，您知道，您只能将组件添加到一个容器中。它只能可见一次。
4. 如果您只是使用第一个代码创建 JFrame 来创建 JPanel，为什么要使用它来创建 JFrame？
5. 你问，“有没有办法复制我设计的面板”——当然。不要像您正在做的那样创建它，而是在某种工厂方法中创建 JPanel。例如，public JPanel createMyPanel() {/* 创建代码在此处 */}
6. 或者创建一个扩展 JPanel 的类并以这种方式创建 JPanel 对象。

例如，下面的类创建一个 JPanel，将字符串列表显示为 JRadioButton 列，然后通知任何观察者选择:

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.List;
import javax.swing.*;
import javax.swing.border.Border;

@SuppressWarnings("serial")
public class BunchARadios extends JPanel {
    private static final int GAP = 5;
    public static final String SELECTION = "selection";
    private ButtonGroup buttonGroup = new ButtonGroup();

    public BunchARadios(String title, List<String> radioLabels) {
        Border innerBorder = BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP);
        Border outerBorder = BorderFactory.createTitledBorder(title);
        Border border = BorderFactory.createCompoundBorder(outerBorder, innerBorder);
        setBorder(border);
        setLayout(new GridLayout(0, 1, GAP, GAP));

        RButtonListener rButtonListener = new RButtonListener();
        for (String radioLabel : radioLabels) {
            JRadioButton radioButton = new JRadioButton(radioLabel);
            radioButton.setActionCommand(radioLabel);
            add(radioButton);
            buttonGroup.add(radioButton);
            radioButton.addActionListener(rButtonListener);
        }        
    }

    public String getSelection() {
        ButtonModel model = buttonGroup.getSelection();
        if (model == null) {
            return null; // throw exception?
        } else {
            return model.getActionCommand();
        }
    }

    private class RButtonListener implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent e) {
            firePropertyChange(SELECTION, null, e.getActionCommand());
        }
    }
}

下面是一个使用上述类/JPanel 的类，它向该类添加了一个 PropertyChangeListener，以便在进行选择时，该类中的另一个组件(JList)可以显示新的选择:

import java.awt.BorderLayout;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Arrays;
import java.util.List;
import javax.swing.*;

@SuppressWarnings("serial")
public class TestBunchARadios extends JPanel {
    private static final int GAP = 5;
    private String title = "Weekdays";
    private List<String> labels = Arrays.asList(new String[] { "Monday", "Tuesday", "Wednesday",
            "Thursday", "Friday" });
    private BunchARadios bunchARadios = new BunchARadios(title, labels);
    private DefaultListModel<String> listModel = new DefaultListModel<>();
    private JList<String> selectionList = new JList<>(listModel);

    public TestBunchARadios() {
        selectionList.setPrototypeCellValue("xxxxxxxxxxxxxxxxx");
        selectionList.setVisibleRowCount(5);
        JScrollPane scrollPane = new JScrollPane(selectionList);
        scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);

        setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
        setLayout(new BorderLayout(GAP, GAP));
        add(bunchARadios, BorderLayout.CENTER);
        add(scrollPane, BorderLayout.LINE_END);

        bunchARadios.addPropertyChangeListener(BunchARadios.SELECTION,
                new BunchARadiosChangeListener());
    }

    private class BunchARadiosChangeListener implements PropertyChangeListener {
        @Override
        public void propertyChange(PropertyChangeEvent evt) {
            String selection = (String) evt.getNewValue();
            listModel.addElement(selection);
        }
    }

    private static void createAndShowGui() {
        TestBunchARadios mainPanel = new TestBunchARadios();

        JFrame frame = new JFrame("TestBunchARadios");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            createAndShowGui();
        });
    }
}