Question

我有组合框的表格。取决于此组合框中的所选项目，表单中的某些字段会隐藏，而某些字段会显示。但是对于窗体重新绘制的JPanel，对话框的大小不会自动调整大小。如何解决这个问题？

Sscce.java：

import javax.swing.*;

public class Sscce extends JFrame {
    Sscce() {
        setTitle("Sscce");
        // Sets the behavior for when the window is closed
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        getContentPane().add(new MainPanel());
        pack();
    }
    public static void main(String[] args) {
        Sscce application = new Sscce();
        application.setVisible(true);
    }
}

MainPanel.java：

import javax.swing.*;

public class MainPanel extends JPanel {
    public MainPanel() {
        final DeviceForm form = new DeviceForm();
        JOptionPane.showConfirmDialog(null, form, "Add new device", JOptionPane.OK_CANCEL_OPTION,
                JOptionPane.PLAIN_MESSAGE);
    }
}

DeviceForm.java：

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

public class DeviceForm extends JPanel implements ActionListener {
    private LinkedHashMap<String, JComponent> fields = new LinkedHashMap<String, JComponent>();
    private HashMap<String, JPanel> borders = new HashMap<String, JPanel>();

    public DeviceForm() {
        String[] versions = {String.valueOf(1), String.valueOf(2),
                String.valueOf(3)};
        JComboBox versionList = new JComboBox(versions);
        versionList.addActionListener(this);
        versionList.setSelectedIndex(0);
        fields.put("Version: ", versionList);

        JTextField textField = new JTextField();
        fields.put("Community: ", textField);

        setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
        for (Map.Entry<String, JComponent> entry : fields.entrySet()) {
            JPanel borderPanel = new JPanel(new java.awt.BorderLayout());
            borderPanel.setBorder(new javax.swing.border.TitledBorder(entry.getKey()));
            borderPanel.add(entry.getValue(), java.awt.BorderLayout.CENTER);
            add(borderPanel);
            borders.put(entry.getKey(), borderPanel);
        }
    }

    /**
     * Repaint form fields for chosen version of SNMP
     * @param e
     */
    public void actionPerformed(ActionEvent e) {
        JComboBox cb = (JComboBox)e.getSource();
        int version = Integer.parseInt((String)cb.getSelectedItem());
        if (version == 1) {    // hide username and password, show community
            JComponent field = borders.get("Username: ");
            if (field != null)
                remove(field);

            field = borders.get("Password: ");
            if (field != null)
                remove(field);


            field = borders.get("Community: ");
            if (field != null)
                add(field);
        }
        else if(version == 3) { // hide community, show username and password
            JComponent field = borders.get("Community: ");
            if (field != null)
                remove(field);

            field = borders.get("Username: ");
            if (field == null)
                addField("Username: ");
            else
                add(field);

            field = borders.get("Password: ");
            if (field == null)
                addField("Password: ");
            else
                add(field);
        }
        validate();
        repaint();
    }

    private void addField(String title) {
        // Create field
        JTextField textField = new JTextField();
        fields.put(title, textField);
        // Border created field
        JPanel borderPanel = new JPanel(new java.awt.BorderLayout());
        borderPanel.setBorder(new javax.swing.border.TitledBorder(title));
        borderPanel.add(textField, java.awt.BorderLayout.CENTER);
        add(borderPanel);
        borders.put(title, borderPanel);
    }
}

Answer 1

解决方案是让您使用CardLayout。

如，

import java.awt.CardLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

@SuppressWarnings("serial")
public class Sscce2 extends JPanel {
   private static final String COMMUNITY = "Community";
   private static final String PASSWORD = "Password";
   private static final String BLANK = "Blank";
   private static final String[] VERSIONS = {COMMUNITY, PASSWORD, BLANK};

   CardLayout cardLayout = new CardLayout();
   JPanel cardHolderPanel = new JPanel(cardLayout);
   JComboBox combobox = new JComboBox(VERSIONS);
   private JPasswordField passwordField = new JPasswordField(15);
   private JTextField communityTextField = new JTextField(15);

   public Sscce2() {
      cardHolderPanel.add(createCommunityPanel(), COMMUNITY);
      cardHolderPanel.add(createPasswordPanel(), PASSWORD);
      cardHolderPanel.add(new JLabel(), BLANK);

      JPanel comboPanel = new JPanel();
      comboPanel.setLayout(new BoxLayout(comboPanel, BoxLayout.PAGE_AXIS));
      comboPanel.setBorder(BorderFactory.createTitledBorder("Version:"));
      comboPanel.add(combobox);

      setLayout(new GridLayout(0, 1));
      add(comboPanel);
      add(cardHolderPanel);

      combobox.addActionListener(new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent e) {
            String selection = combobox.getSelectedItem().toString();
            cardLayout.show(cardHolderPanel, selection);
         }
      });
   }

   public String getCommunityText() {
      return communityTextField.getText();
   }

   public char[] getPassword() {
      return passwordField.getPassword();
   }


   private JPanel createCommunityPanel() {
      JPanel panel = new JPanel();
      panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
      panel.setBorder(BorderFactory.createTitledBorder(COMMUNITY));
      panel.add(communityTextField);
      return panel;
   }


   private JPanel createPasswordPanel() {
      JPanel panel = new JPanel();
      panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
      panel.setBorder(BorderFactory.createTitledBorder(PASSWORD));
      panel.add(passwordField);
      return panel;
   }


   private static void createAndShowGui() {
      Sscce2 sscce2 = new Sscce2();
      JOptionPane.showMessageDialog(null, sscce2, "SSCCE 2", JOptionPane.PLAIN_MESSAGE);

      System.out.println("Community text: " + sscce2.getCommunityText());
      System.out.println("Password: " + new String(sscce2.getPassword())); // *** never do this!
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

从内部面板调用JOptionPane重绘

1 个答案: