Aktualisieren Sie eine JLabel

Question

Dies ist, wie der Titel sagt, brauche ich Ihre Hilfe, um den Inhalt eines JLabel zu aktualisieren.

Ich erkläre meine Sorgen. Ich habe eine erste JFarm oder ich habe einen Kalender (einen DatePicker), der mir erlaubt, ein Datum und eine Taste auszuwählen. Wenn ich auf den Button klicke öffnet sich ein neues Fenster und in diesem berühmten Fenster habe ich mein JLabel oder ich möchte mein Date sehen.

In diesem letzten Fenster schrieb ich:

System.out.println(datePicker.getDate()); 
labelDate.setText(datePicker.getDate()); 

Als ich zum ersten Mal öffne mein Fenster alles funktioniert gut, aber wenn ich es schließen, ändere ich das Datum in meinem Datepicker und das Fenster wieder öffnen, indem Sie auf meiner Schaltfläche klicken Das Datum ändert sich nicht !!! Es bleibt immer am ersten Datum gesendet.

Doch meine:

System.out.println(datePicker.getDate()); 

Gibt das richtige Datum richtig jedes Mal.

Haben Sie eine Idee? Danke euch allen.

Answer 1

Wieder ich,

Ich habe meinen Fehler gefunden! In meinem WindowAbsence:

private static JPanel panelWindow = new JPanel(new BorderLayout()); 

Das Panel es in statischen war ... i für jemanden dienen hoffen!

Answer 2

Ich poste meinen vollen Code, aber es ist sehr lang und nicht sehr sauber ... sorry.

das Hauptfenster:

public class App extends JFrame{ 

    private JPanel contentPane; 
    static final int rowMultiplier = 4; 
    private DatePicker datePicker; 


    /** 
    * Launch the application. 
    */ 
    public static void main(String[] args) { 
     EventQueue.invokeLater(new Runnable() { 
      public void run() { 
       try { 
        App frame = new App(); 
        frame.setVisible(true); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
      } 
     }); 
    } 

    public App() throws SQLException{ 
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     setBounds(100, 100, 450, 300); 
     this.setTitle("Absences Management"); 
     contentPane = new JPanel(); 
     contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); 
     contentPane.setLayout(new BorderLayout(0, 0)); 
     setContentPane(contentPane); 


// =================== PanelTitle ===================================  
     JPanel panelTitle = new JPanel(); 
     contentPane.add(panelTitle, BorderLayout.NORTH); 

     JLabel labelTitle = new JLabel("Absence Management"); 
     panelTitle.add(labelTitle); 

// ================== PanelMenu ===================================== 
     JPanel panelMenu = new JPanel(); 
     contentPane.add(panelMenu, BorderLayout.WEST); 
     panelMenu.setLayout(new BoxLayout(panelMenu, BoxLayout.Y_AXIS)); 


     // Border and name for the panel 
     panelMenu.setBorder(BorderFactory.createTitledBorder(" Menu ")); 


     // create buttons and set the actions for the menu 
     JButton buttonAddClass = new JButton(new ActionButtonClassManagement(this,"Class management")); 
     JButton buttonQuit = new JButton(new ActionButtonQuit(this,"  Quit  ")); 


     // add different components in the Panel Menu 
     panelMenu.add(buttonAddClass); 
     panelMenu.add(buttonQuit); 



// ================= PanelCalendar ==================================  

     JPanel panelCalendar = new JPanel(); 
     contentPane.add(panelCalendar, BorderLayout.CENTER); 
     panelCalendar.setAlignmentX(CENTER_ALIGNMENT); 

     // black border for the panel 
     panelCalendar.setBorder(BorderFactory.createTitledBorder(" Calendar ")); 

     JLabel labelCalendar = new JLabel("CALENDAR :");   
     panelCalendar.add(labelCalendar); 

     // ===== create the calendar 
     // settings 
     DatePickerSettings dateSettings = new DatePickerSettings(); 
     dateSettings.setVisibleClearButton(false); 
     // set the current date by default 
     dateSettings.setAllowEmptyDates(false); 

     datePicker = new DatePicker(dateSettings); 


     // create a icon 
     URL dateImageURL = FullDemo.class.getResource("/img/calendar20x20.png"); 
     Image calendarImage = Toolkit.getDefaultToolkit().getImage(dateImageURL); 
     ImageIcon calendarIcon = new ImageIcon(calendarImage); 

     // create button and set the icon 
     JButton datePickerButton = datePicker.getComponentToggleCalendarButton(); 
     datePickerButton.setText(""); 
     datePickerButton.setIcon(calendarIcon); 

     // add the calendar to the PanelCalendar 
     panelCalendar.add(datePicker); 
     // create a button Show absences 
     JButton buttonAbsence = new JButton(new ActionButtonAbsences(this,"Absences", datePicker)); 

     //add the button to the panelCalendar 
     panelCalendar.add(buttonAbsence); 

    } 

} 

Die Klasse für meine Taste Abwesenheit:

public class ActionButtonAbsences extends AbstractAction{ 

    private App windowAbsence; 
    private DatePicker datePicker = new DatePicker(); 
    private String dateString = new String(); 

    public ActionButtonAbsences(App app, String textButton, DatePicker datePicker) { 
     // TODO Auto-generated constructor stub 
     super(textButton); 
     this.datePicker = datePicker; 
    } 

    @Override 
    public void actionPerformed(ActionEvent arg0) { 
     // TODO Auto-generated method stub 
     dateString = datePicker.getText(); 
     WindowAbsence fen = new WindowAbsence(windowAbsence, datePicker, dateString); 
    } 
} 

Und das Fenster, das sich öffnet, wenn ich drücken Sie die Taste Abwesenheit:

public class WindowAbsence extends JDialog implements ActionListener{ 


    private static JPanel panelWindow = new JPanel(new BorderLayout()); 
    private JPanel panelTitle = new JPanel(); 
    private JPanel panelWindowLeft = new JPanel(); 
    private JPanel panelWindowRight = new JPanel(); 

    private JComboBox comboBoxClass; 
    private JComboBox comboBoxStudent; 
    private DatePicker datePicker; 
    private JLabel labelDate = new JLabel(); 
    private String dateString = new String(); 

    private ModelTable modelTableAbsence = new ModelTable(); 
    private JTable tableAbsence = new JTable(modelTableAbsence); 


    public WindowAbsence(Frame frame, DatePicker datePicker, String date){ 
     //super call the constructor of the main window 
     // the first argument is the mother window 
     // the second argument disable this window 
     super(frame,true); 

     labelDate.setText(datePicker.getText()); 

     this.dateString = date; 


     // add BorderLayout in this Window 
     this.setLayout(new BorderLayout()); 

     // name of the window 
     this.setTitle("Absences"); 
     // size of the window 
     this.setSize(700, 600); 
     // effect for the red cross 
     this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 
     this.setLocationRelativeTo(null); 

     this.datePicker = datePicker; 

     // =================== Data bases connection ============================    
     /** 
     * download mysql-connector-java-5.1.40.tar.gz 
     * https://dev.mysql.com/downloads/file/?id=470332 
     * Clic droit sur le dossier du projet 
     * Clic right on the folder of the project 
     * Build Path 
     * Add external Archive 
     */ 

     DataBase database = new DataBase(); 
     String url = "jdbc:mysql://localhost:3306/AbsenceManagement"; 
     String user = "root"; 
     String pass = ""; 
     String driver = "com.mysql.jdbc.Driver"; 

     try { 
      database.connectionDataBase(url, user, pass, driver); 


    // ================== PANEL TITLE ================================== 
      //JLabel labelDate = new JLabel(); 
      panelTitle.add(labelDate); 
      //labelDate.setText(datePicker.getText()); 
      date = datePicker.getText(); 

      System.out.println("date: "+date); 
      labelDate.setText(date); 


      panelWindow.add(panelTitle, BorderLayout.NORTH); 

     // ================ PANEL LEFT ===================================== 
     panelWindowLeft.setBorder(BorderFactory.createTitledBorder(" Absences ")); 
      // =========== panelComboBoxLabelClass ====================== 
     JPanel panelLabelComboBoxClass = new JPanel(); 
     panelLabelComboBoxClass.setLayout(new BoxLayout(panelLabelComboBoxClass, BoxLayout.LINE_AXIS)); 
     JLabel labelComboBoxClass = new JLabel("Class :"); 
     comboBoxClass = new JComboBox(); 
     comboBoxClass.addItem(""); 
     panelLabelComboBoxClass.add(labelComboBoxClass); 
     panelLabelComboBoxClass.add(comboBoxClass);  


     Statement statementClass = DataBase.connection.createStatement(); 
     ResultSet resultClass = statementClass.executeQuery("SELECT class FROM Class"); 

     //receive the MetaData 
     ResultSetMetaData resultMetaClass = (ResultSetMetaData) resultClass.getMetaData(); 

     // add the data in the row 
     while(resultClass.next()){ 
      comboBoxClass.addItem(resultClass.getObject(1)); 
     } 

     comboBoxClass.addActionListener(this); 


     resultClass.close(); 
     statementClass.close(); 

      // =========== panelComboBoxLabelStudent ====================== 
     JPanel panelLabelComboBoxStudent = new JPanel(); 
     panelLabelComboBoxStudent.setLayout(new BoxLayout(panelLabelComboBoxStudent, BoxLayout.LINE_AXIS)); 
     JLabel labelComboBoxStudent = new JLabel("Student :"); 
     comboBoxStudent = new JComboBox(); 
     panelLabelComboBoxStudent.add(labelComboBoxStudent); 
     panelLabelComboBoxStudent.add(comboBoxStudent); 

     // ========== panelComboBoxHour =============================== 
     int rowMultiplier = 4; 
     int row = rowMultiplier; 

     TimePickerSettings timeSettings = new TimePickerSettings(); 
     timeSettings.setDisplayToggleTimeMenuButton(true); 
     timeSettings.setDisplaySpinnerButtons(false); 



     JPanel panelComboBoxHour = new JPanel(); 
     panelComboBoxHour.setLayout(new BoxLayout(panelComboBoxHour, BoxLayout.LINE_AXIS)); 


     JLabel labelComboBoxFrom = new JLabel("From :"); 
     panelComboBoxHour.add(labelComboBoxFrom); 

     TimePicker timePickerFrom = new TimePicker(timeSettings); 
     timePickerFrom = new TimePicker(); 
     panelComboBoxHour.add(timePickerFrom, getConstraints(1, (row * rowMultiplier), 1)); 
     //panelComboBoxHour.addLabel(panelComboBoxHour, 1, (row++ * rowMultiplier), "Time 1, Default Settings:"); 


     JLabel labelComboBoxTo = new JLabel("To :"); 
     panelComboBoxHour.add(labelComboBoxTo); 

     TimePicker timePickerTo = new TimePicker(); 
     timePickerTo = new TimePicker(); 
     panelComboBoxHour.add(timePickerTo, getConstraints(1, (row * rowMultiplier), 1)); 

     // ========== panel button add absence ============== 
     JPanel panelButtonAddAbsence = new JPanel(); 
     panelButtonAddAbsence.setLayout(new BoxLayout(panelButtonAddAbsence, BoxLayout.LINE_AXIS)); 

     JButton buttonAddAbsence = new JButton("Add Absence"); 
     panelButtonAddAbsence.add(buttonAddAbsence); 
     // ======================================== 

     panelWindowLeft.setLayout(new BoxLayout(panelWindowLeft, BoxLayout.PAGE_AXIS)); 
     panelWindowLeft.add(panelLabelComboBoxClass); 
     panelWindowLeft.add(panelLabelComboBoxStudent); 
     panelWindowLeft.add(panelComboBoxHour); 
     panelWindowLeft.add(panelButtonAddAbsence); 

     panelWindow.add(panelWindowLeft, BorderLayout.WEST); 
     // ====================== PANEL RIGHT ================================ 


     panelWindowRight.setBorder(BorderFactory.createTitledBorder(" Absences ")); 


     //=================== TABLE ======================================= 

     Statement statementAbsence = DataBase.connection.createStatement(); 
     // requet SQL 
     ResultSet resultAbsence; 
     ResultSetMetaData resultMetaAbsence;   

     modelTableAbsence.addColumn("Student"); 
     modelTableAbsence.addColumn("Date"); 
     modelTableAbsence.addColumn("To"); 
     modelTableAbsence.addColumn("From"); 

     // requete SQL 
     resultAbsence = statementAbsence.executeQuery("SELECT * FROM Absence WHERE `dateAbsence`='"+datePicker.getDate().toString()+"'"); 

     //receive the MetaData 
     resultMetaAbsence = (ResultSetMetaData) resultAbsence.getMetaData(); 
     modelTableAbsence.fireTableDataChanged(); 

     if(!resultAbsence.next()){ 
      System.out.println("null"); 
     }else{ 
      // add the data in the row 
      do{ 
        modelTableAbsence.addRow(new Object[]{ 
          resultAbsence.getObject(2).toString(), 
          resultAbsence.getObject(3).toString(), 
          resultAbsence.getObject(4).toString(), 
          resultAbsence.getObject(5).toString() 
        }); 
      }while(resultAbsence.next()); 
      // close the statementClass 
      statementAbsence.close(); 
      resultAbsence.close(); 


      // ========= replace id student by firstName and lastName 
      Statement statementNameStudent = DataBase.connection.createStatement(); 
      ResultSet resultNameStudent = null; 

      int nbRow = modelTableAbsence.getRowCount(); 
      for(int i = 0; i < nbRow; i++){ 

       resultNameStudent = statementNameStudent.executeQuery("SELECT firstName, lastName FROM Student WHERE `id`='"+modelTableAbsence.getValueAt((i), 0)+"'"); 
       // add the data in the row 
        while(resultNameStudent.next()){ 
         modelTableAbsence.setValueAt(
           (resultNameStudent.getObject(1)+" "+resultNameStudent.getObject(2)),i,0); 
        } 
      } 
      statementNameStudent.close(); 
      resultNameStudent.close(); 

     } 

     // ================================================================= 
     JScrollPane scrollPane = new JScrollPane(tableAbsence); 

     panelWindowRight.add(scrollPane); 
     panelWindow.add(panelWindowRight, BorderLayout.CENTER); 

     this.setContentPane(panelWindow); 
     this.setVisible(true); 

     } catch (SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 

    } 

    private static GridBagConstraints getConstraints(int gridx, int gridy, int gridwidth) { 
     GridBagConstraints gc = new GridBagConstraints(); 
     gc.fill = GridBagConstraints.NONE; 
     gc.anchor = GridBagConstraints.WEST; 
     gc.gridx = gridx; 
     gc.gridy = gridy; 
     gc.gridwidth = gridwidth; 
     return gc; 
} 
    // model table for table schedule 
    public class ModelTableSchedule extends DefaultTableModel { 
     ModelTableSchedule(Object[][] dataStudent, String[] columnNamesStudent) { 
      super(dataStudent, columnNamesStudent); 
     } 
     // the function return always false, the table is never editable 
     @Override 
     public boolean isCellEditable(int row, int column) { 
      return false; 
     } 
    } 

    public void actionPerformed(ActionEvent arg0) { 


     modelTableAbsence.fireTableDataChanged(); 


     // =================== Data bases connection ============================    
     /** 
     * download mysql-connector-java-5.1.40.tar.gz 
     * https://dev.mysql.com/downloads/file/?id=470332 
     * Clic droit sur le dossier du projet 
     * Clic right on the folder of the project 
     * Build Path 
     * Add external Archive 
     */ 

     DataBase database = new DataBase(); 
     String url = "jdbc:mysql://localhost:3306/AbsenceManagement"; 
     String user = "root"; 
     String pass = ""; 
     String driver = "com.mysql.jdbc.Driver"; 

      try { 
       database.connectionDataBase(url, user, pass, driver); 

       // add value in ComboBox 
       Statement statementStudent; 
       comboBoxStudent.removeAllItems(); 
       statementStudent = DataBase.connection.createStatement(); 
       ResultSet resultStudent = statementStudent.executeQuery("SELECT * FROM `Student` WHERE `class` LIKE '"+comboBoxClass.getSelectedItem().toString()+"'"); 
       //receive the MetaData 
       ResultSetMetaData resultMetaStudent = (ResultSetMetaData) resultStudent.getMetaData();  
       // add the data in the row 
       while(resultStudent.next()){ 
        comboBoxStudent.addItem((resultStudent.getObject(2)+" "+resultStudent.getObject(3))); 
       } 
       comboBoxStudent.revalidate(); 
       resultStudent.close(); 
       statementStudent.close(); 

      } catch (SQLException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
    } 
} 

Danke für deine Hilfe.