正如标题所说，我需要你的帮助来刷新JLabel的内容。
我解释了我的担忧。 我有一个第一个JFarm或者我有一个日历（一个DatePicker），它允许我选择一个日期和一个按钮。 当我点击按钮时，它会打开一个新窗口，在这个着名的窗口中，我有我的JLabel，或者我希望看到我的日期。
在最后一个窗口我写道：
System.out.println(datePicker.getDate());
labelDate.setText(datePicker.getDate());
当我第一次打开窗口时，一切正常，但是如果我关闭它，我会更改DatePicker中的日期并通过单击我的按钮重新打开窗口，日期不会改变！ 它始终保留在发送的第一个日期。
然而我的：
System.out.println(datePicker.getDate());
每次都正确返回正确的日期。
你知道吗？ 谢谢大家。答案 0 :(得分：0)
我发布了我的完整代码，但它很长，而且不是很干净......抱歉。
主窗口：
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);
}
}
我按钮的课程缺席：
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);
}
}
按下按钮时打开的窗口缺席：
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();
}
}
}
感谢您的帮助。
答案 1 :(得分：0)
再次我，
我发现了我的错误！ 在我的WindowAbsence中：
private static JPanel panelWindow = new JPanel(new BorderLayout());
它处于静态的面板...... 我希望能为某人服务！