JListが別のペインで更新されない（Swing、Java）

Question

私の最初の「パスワードボールト」タブでは、パスワードを保存する「ウェブサイト」のリストを持つJListがあります。 2番目のタブには「パスワード」機能が追加されています。パスワードを追加すると、JListはペインでのみ更新されます。もう一度他のタブ「パスワードボールト」に切り替えると、更新されていません。プログラムを再起動すると、更新されました。フィールドを使用するので、ローカル変数の問題ではありません。

public final class PasswordManagerView1 extends JFrame 
    implements PasswordManagerView, ListSelectionListener { 
/** 
* JList. 
*/ 
private JList<String> list; 

/** 
* JButtons. 
*/ 
private JButton enter, unlock, reset, buttonAddEnter; 

/** 
* Controller. 
*/ 
private PasswordManagerController controller; 

/** 
* Dimensions. 
*/ 
private Dimension maxSize; 

/** 
* JTabbedPanes. 
*/ 
private JTabbedPane tabbedPane; 

/** 
* JTextField. 
*/ 
private JTextField passwordDisplay, textField; 

/** 
* PasswordField. 
*/ 
private JPasswordField passwordField, resetField, passwordFieldadd; 

/** 
* Useful Constants. 
*/ 
private static final int MAX_SIZE_HORI = 800, MAX_SIZE_VERTI = 400, 
     EMPTY_BORDER_SIZE = 5; 

/** 
* Constructor. 
*/ 
public PasswordManagerView1() { 
    super("Password Manager"); 
    JTabbedPane tabbedPane = new JTabbedPane(); 
    //Initial JPanel creation 
    tabbedPane.setBorder(
      new EmptyBorder(PasswordManagerView1.EMPTY_BORDER_SIZE, 
        PasswordManagerView1.EMPTY_BORDER_SIZE, 
        PasswordManagerView1.EMPTY_BORDER_SIZE, 
        PasswordManagerView1.EMPTY_BORDER_SIZE)); 
    this.maxSize = new Dimension(PasswordManagerView1.MAX_SIZE_HORI, 
      PasswordManagerView1.MAX_SIZE_VERTI); 
    tabbedPane.setPreferredSize(this.maxSize); 
    this.getContentPane().add(tabbedPane); 

    //Initial JTabbedPane creation 

    //Tab creation 
    JComponent panel1 = this.makePasswordVault(); 
    ImageIcon icon = new ImageIcon("lock-icon.png"); 
    tabbedPane.addTab("Password Vault", icon, panel1, 
      "View the passwords in the vault"); 
    JComponent panel3 = this.makeAddPanel("Add Password"); 
    tabbedPane.addTab("Add Password", icon, panel3, 
      "Add passwords to the vault"); 
    //JComponent panel2 = this.makeAddPanel("ALSO ADDS"); 
    //tabbedPane.addTab("Delete Password", icon, panel2, 
    //  "Deletes a password from the vault"); 

    JComponent panel4 = this.makeInfoPanel(); 
    tabbedPane.addTab("Info", icon, panel4, 
      "View settings and program info"); 
    //Pack up 
    this.setResizable(false); 
    this.pack(); 
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    this.setVisible(true); 
} 

@Override 
public JComponent makeAddPanel(String text) { 
    JPanel panel = new JPanel(); 
    panel.setLayout(null); 
    //Creation of string array of with stores 
    String[] listContentC = this.getStore(); 

    this.list = new JList<>(listContentC); 
    this.list.setBounds(0, 0, 233, 360); 
    JScrollPane pane = new JScrollPane(this.list); 
    pane.setBounds(0, 0, 233, 360); 
    panel.add(pane); 
    JLabel labelAdd = new JLabel("Add Password"); 
    labelAdd.setHorizontalAlignment(SwingConstants.CENTER); 
    labelAdd.setFont(new Font("Times New Roman", Font.PLAIN, 24)); 
    labelAdd.setBounds(427, 38, 163, 31); 
    panel.add(labelAdd); 

    this.passwordFieldadd = new JPasswordField(); 
    this.passwordFieldadd.setBounds(536, 100, 116, 22); 
    panel.add(this.passwordFieldadd); 

    this.textField = new JTextField(); 
    this.textField.setBounds(375, 100, 116, 22); 
    panel.add(this.textField); 

    JLabel lblWebsite = new JLabel("Website"); 
    lblWebsite.setHorizontalAlignment(SwingConstants.CENTER); 
    lblWebsite.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    lblWebsite.setBounds(401, 126, 56, 16); 
    panel.add(lblWebsite); 

    JLabel lblPassword = new JLabel("Password"); 
    lblPassword.setHorizontalAlignment(SwingConstants.CENTER); 
    lblPassword.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    lblPassword.setBounds(566, 126, 56, 16); 
    panel.add(lblPassword); 

    this.buttonAddEnter = new JButton("Enter"); 
    this.buttonAddEnter.setBounds(465, 161, 97, 25); 
    panel.add(this.buttonAddEnter); 
    this.buttonAddEnter.addActionListener(this); 
    return panel; 
} 

@Override 
public JComponent makeInfoPanel() { 
    JPanel panel = new JPanel(); 
    panel.setLayout(new GridLayout(1, 1)); 
    StringBuilder toPrint = new StringBuilder(); 
    SimpleReader in = new SimpleReader1L("data/Notice.txt"); 
    while (!in.atEOS()) { 
     toPrint.append(in.nextLine() + "\n"); 
    } 
    String toPrintString = toPrint.toString(); 
    JTextArea noticeText = new JTextArea(toPrintString); 
    noticeText.setEditable(false); 
    JScrollPane noticeTextScroll = new JScrollPane(noticeText); 
    panel.add(noticeTextScroll); 
    in.close(); 
    return panel; 

} 

@Override 
public JComponent makePasswordVault() { 
    JPanel panel = new JPanel(); 
    panel.setLayout(null); 
    /* 
    * Ask for help on this. 
    * 
    * I would have liked to create the listContentC by passing nothing into 
    * the controller and then the controller using the model to extract the 
    * data from a text file. However, my array was always initialized to 
    * something null and caused a runtime error. 
    * 
    * 
    */ 

    //Creation of string array of with stores 
    String[] listContentC = this.getStore(); 

    //GUI setup of list 
    this.list = new JList<>(listContentC); 
    this.list.setLayoutOrientation(JList.VERTICAL); 
    this.list.addListSelectionListener(this); 
    JScrollPane pane = new JScrollPane(this.list); 
    pane.setBounds(0, 0, 233, 360); 
    panel.add(pane); 

    //The label creation (for instructions) 
    JLabel labelA = new JLabel("the store and press enter!"); 
    labelA.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    labelA.setBounds(294, 70, 157, 31); 
    panel.add(labelA); 
    JLabel labelB = new JLabel("To view a password, click on"); 
    labelB.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    labelB.setBounds(284, 54, 163, 31); 
    panel.add(labelB); 

    //Enter button creation 
    this.enter = new JButton("Enter"); 
    this.enter.setBounds(303, 128, 116, 25); 
    panel.add(this.enter); 
    this.enter.setEnabled(false); 
    this.enter.addActionListener(this); 

    //Password Display field creation 
    this.passwordDisplay = new JTextField(); 
    this.passwordDisplay.setBackground(Color.WHITE); 
    this.passwordDisplay.setEditable(false); 
    this.passwordDisplay 
      .setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    this.passwordDisplay.setHorizontalAlignment(SwingConstants.CENTER); 
    this.passwordDisplay.setText(""); 
    this.passwordDisplay.setBounds(303, 247, 116, 22); 
    panel.add(this.passwordDisplay); 
    this.passwordDisplay.setColumns(10); 

    //Password Label creation 
    JLabel passwordLabel = new JLabel("Password:"); 
    passwordLabel.setHorizontalAlignment(SwingConstants.CENTER); 
    passwordLabel.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    passwordLabel.setBounds(336, 218, 56, 16); 
    panel.add(passwordLabel); 

    //Master password notice 
    JLabel mastPass = new JLabel("Enter master password to unlock vault:"); 
    mastPass.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    mastPass.setBounds(532, 54, 218, 31); 
    panel.add(mastPass); 

    //Password Field 
    this.passwordField = new JPasswordField(); 
    this.passwordField.setBounds(532, 128, 116, 24); 
    panel.add(this.passwordField); 

    //Unlock button 
    this.unlock = new JButton("Unlock"); 
    this.unlock.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    this.unlock.setBounds(660, 127, 97, 25); 
    panel.add(this.unlock); 
    this.unlock.addActionListener(this); 

    //New setup label 
    JLabel labelC = new JLabel("Reset/Set up new master pass:"); 
    labelC.setHorizontalAlignment(SwingConstants.CENTER); 
    labelC.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    labelC.setBounds(532, 217, 218, 16); 
    panel.add(labelC); 

    //New setup label 
    JLabel defaultLabel = new JLabel("Default Password = \"password\""); 
    defaultLabel.setHorizontalAlignment(SwingConstants.CENTER); 
    defaultLabel.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    defaultLabel.setBounds(560, 77, 171, 16); 
    panel.add(defaultLabel); 

    this.resetField = new JPasswordField(); 
    this.resetField.setBounds(532, 246, 116, 24); 
    panel.add(this.resetField); 

    this.reset = new JButton("Update"); 
    this.reset.setFont(new Font("Times New Roman", Font.PLAIN, 13)); 
    this.reset.setBounds(660, 245, 97, 25); 
    this.reset.setEnabled(false); 
    panel.add(this.reset); 
    this.reset.addActionListener(this); 
    return panel; 
} 

@Override 
public String[] getStore() { 

    int storeCount = 0; 
    SimpleReader in = new SimpleReader1L("data/store.txt"); 
    while (!in.atEOS()) { 
     storeCount++; 
     in.nextLine(); 
    } 
    in.close(); 
    String[] listContentC = new String[storeCount]; 
    SimpleReader in2 = new SimpleReader1L("data/store.txt"); 
    for (int i = 0; i < storeCount; i++) { 
     listContentC[i] = in2.nextLine(); 
    } 
    in2.close(); 
    return listContentC; 
} 

@Override 
public void registerObserver(PasswordManagerController controller) { 
    this.controller = controller; 
} 

@Override 
public void updateEnterButtonVaultTab(boolean result) { 
    this.enter.setEnabled(result); 
} 

@Override 
public void actionPerformed(ActionEvent event) { 
    //Wait cursor 
    this.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR)); 

    //What button was pressed 
    Object source = event.getSource(); 
    if (source == this.enter) { 
     int index = this.list.getSelectedIndex(); 
     System.out.println(index); 
     if (this.list.getSelectedIndex() != -1) { 
      this.controller.processEnterEvent(this.list.getSelectedValue()); 
     } 
    } else if (source == this.unlock) { 
     this.controller 
       .processUnlockEvent(this.passwordField.getPassword()); 
    } else if (source == this.reset) { 
     this.controller.processResetEvent(this.resetField.getPassword()); 
    } else if (source == this.buttonAddEnter) { 
     this.controller.processAddEvent(this.textField.getText(), 
       this.passwordFieldadd.getPassword()); 
     //needs done in model 
     this.updateListModel(); 
    } 
    this.setCursor(Cursor.getDefaultCursor()); 
} 

@Override 
public void updateListModel() { 
    //MOVE TO THE MODEL 
    String[] temp = this.getStore(); 
    DefaultListModel<String> temp2 = new DefaultListModel<>(); 
    for (int i = 0; i < temp.length; i++) { 
     temp2.addElement(temp[i]); 
    } 
    this.list.setModel(temp2); 
} 

@Override 
public JTabbedPane getTabbedPane() { 
    return this.tabbedPane; 
} 

@Override 
public void setTabbedPane(JTabbedPane tabbedPane) { 
    this.tabbedPane = tabbedPane; 
} 

@Override 
public void updatePasswordField() { 
    this.passwordField.setText(""); 
} 

@Override 
public void updateResetPasswordDisplay() { 
    this.resetField.setText(""); 
} 

@Override 
public void displayWrongPass() { 
    JOptionPane.showMessageDialog(this, "Wrong password entered!"); 

} 

@Override 
public void displayUpdatedPass() { 
    JOptionPane.showMessageDialog(this, "Master password updated!"); 
} 

@Override 
public void updateResetButton(boolean result) { 
    this.reset.setEnabled(result); 
} 

@Override 
public void updatePasswordDisplay(char[] password) { 
    StringBuilder passwordCreation = new StringBuilder(); 
    for (int i = 0; i < password.length; i++) { 
     passwordCreation.append(password[i]); 
    } 
    this.passwordDisplay.setText(passwordCreation.toString()); 

} 

@Override 
public JComponent makeTextPanel(String text) { 
    // TODO Auto-generated method stub 
    return null; 
} 

@Override 
public void valueChanged(ListSelectionEvent arg0) { 

} 

} 

Answer 1

この場合も、すべて同じコンテンツを表示する複数のJListsを表示するには、すべて同じモデルを共有する必要があります。これを行うと、実際にJList自体（モデルのコンテンツのみを表示する）ではなく、共有モデルに変更が実際に加えられたため、あるJListに対する変更は他のすべてのJListに反映されます。これを理解するには、Swingコンポーネントがバリアントを使用しているので、MVCまたはModel-View-Controllerのデザインパターンを読みたいと思うでしょう。

たとえば、それぞれ独自のJListを持つ3つのJPanelを作成したが、それらのすべてが同じDefaultListModel<String>を共有しているコードをご覧ください。実際にJListを保持し、そのコンストラクタでモデルを受け入れる親クラスから3つのJPanelがすべて伸びていることに注意してください。次に、1つのJPanelにリスト項目を追加したり、別のJPanelでリスト項目を削除したりすると、それらはすべて3つのJPanelのすべてのリストに表示されます。 、早いほど良いのヘルプについて

import java.awt.BorderLayout; 
import java.awt.Dimension; 
import java.awt.event.ActionEvent; 
import java.awt.event.KeyEvent; 
import javax.swing.*; 

@SuppressWarnings("serial") 
public class PanelsWithSharedList extends JPanel { 
    private static final int PREF_W = 400; 
    private static final int PREF_H = 250; 
    private JTabbedPane tabbedPane = new JTabbedPane(); 
    private DefaultListModel<String> listModel = new DefaultListModel<>(); 

    public PanelsWithSharedList() { 
     for (int i = 0; i < 10; i++) { 
      listModel.addElement("List element " + (i + 1)); 
     } 

     setLayout(new BorderLayout()); 
     add(tabbedPane); 
     tabbedPane.add("Panel 1", new ListShowingPanel1(listModel)); 
     tabbedPane.add("Panel 2", new ListShowingPanel2(listModel)); 
     tabbedPane.add("Panel 3", new ListShowingPanel3(listModel)); 
    } 

    @Override 
    public Dimension getPreferredSize() { 
     Dimension superSz = super.getPreferredSize(); 
     if (isPreferredSizeSet()) { 
      return superSz; 
     } 
     int prefW = Math.max(superSz.width, PREF_W); 
     int prefH = Math.max(superSz.height, PREF_H); 
     return new Dimension(prefW, prefH); 
    } 

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

     JFrame frame = new JFrame("Panels With Shared List"); 
     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()); 
    } 
} 

@SuppressWarnings("serial") 
abstract class AbstractListShowingPanel extends JPanel { 
    private JList<String> list; 

    public AbstractListShowingPanel(DefaultListModel<String> listModel) { 
     list = new JList<>(listModel); 
     list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); 
    } 

    public JList<String> getList() { 
     return list; 
    } 

    public DefaultListModel<String> getModel() { 
     return (DefaultListModel<String>) list.getModel(); 
    } 
} 

@SuppressWarnings("serial") 
class ListShowingPanel1 extends AbstractListShowingPanel { 
    private JTextField textField = new JTextField(10); 

    public ListShowingPanel1(DefaultListModel<String> listModel) { 
     super(listModel); 
     add(new JScrollPane(getList())); 
     add(new JLabel("Text to add:")); 

     Action action = new AddTextAction(); 
     textField.setAction(action); 
     add(textField); 
     add(new JButton(action)); 

    } 

    private class AddTextAction extends AbstractAction { 
     public AddTextAction() { 
      super("Add Text"); 
      putValue(MNEMONIC_KEY, KeyEvent.VK_A); 
     } 

     @Override 
     public void actionPerformed(ActionEvent e) { 
      getModel().addElement(textField.getText()); 
      textField.selectAll(); 
     } 
    } 

} 

@SuppressWarnings("serial") 
class ListShowingPanel2 extends AbstractListShowingPanel { 
    public ListShowingPanel2(DefaultListModel<String> listModel) { 
     super(listModel); 
     add(new JScrollPane(getList())); 
     add(new JButton(new DeleteItemAction())); 
    } 

    private class DeleteItemAction extends AbstractAction { 
     public DeleteItemAction() { 
      super("Delete Selected Item"); 
      putValue(MNEMONIC_KEY, KeyEvent.VK_D); 
     } 

     public void actionPerformed(ActionEvent e) { 
      JList<String> list = getList(); 
      String selection = list.getSelectedValue(); 
      if (selection != null) { 
       getModel().removeElement(selection); 
      } 
     } 
    } 
} 

@SuppressWarnings("serial") 
class ListShowingPanel3 extends AbstractListShowingPanel { 
    public ListShowingPanel3(DefaultListModel<String> listModel) { 
     super(listModel); 
     setLayout(new BorderLayout()); 
     add(new JScrollPane(getList())); 
    } 
} 

Answer 2

ただ、ビューの学術的観点から、私はグラフィック要素とその下にあるデータモデル間の関係のこの種は、Observerパターン（https://en.wikipedia.org/wiki/Observer_pattern）として実施されるべきであることを示唆しています。 5つまたは6つのGUI要素がすべて同じ共有データ構造の変更に反応するようになると、すぐにわかりやすく維持しにくくなるかもしれません。

Answer 3

あなたのコンストラクタは、このラインを持っているmakePasswordPanel（）を呼び出します。

this.list = new JList<>(listContentC); 

コンストラクタは、この行があるmakeAddPanel（）を呼び出します。だから今、あなたがハンドルを捨ててきた

this.list = new JList<>(listContentC); 

を最初のリストを新しいリストへの参照に置き換えます。次にupdateListModelで、this.listのモデルを変更します（これはmakeAddPanelリストです）。パネルへの参照を破棄したので、パスワードパネルのモデルも更新する方法はありません。