Develop Reference

Java how do I access text field

I'm relatively new to programming. Hoping someone can help. I have a button that creates a series of labels and text boxes within a frame once the user enters a number. I'm having trouble access the text boxes once they are created. Can someone point me in the right direction. Code snips below. Thanks.
method to create a label and text box.
public JTextField createPrizePanels(){
JLabel prizePanel = new JLabel("Enter Prize Here", SwingConstants.CENTER);
prizePanel.setVerticalAlignment(SwingConstants.TOP);
prizePanel.setFont(new Font("Arial", Font.BOLD, 14));
prizePanel.setForeground(Color.BLUE);
Border border = BorderFactory.createLineBorder(Color.GRAY, 1);
prizePanel.setBorder(border);
prizePanel.setOpaque(true);
prizePanel.setBackground(Color.LIGHT_GRAY);
prizePanel.setBounds(setBoundsX, setBoundsY, 120, 60);
prizeTextBox = new JTextField(50);
prizeTextBox.setBounds(setBoundsX + 5, setBoundsY + 20, 110, 30);
prizeTextBox.setFont(new Font("Arial", Font.BOLD, 12));
prizeTextBox.setOpaque(true);
prizeTextBox.setBackground(Color.WHITE);
prizeTextBox.setForeground(Color.BLACK);
prizeTextBox.setText("No Prize");
prizeTextBox.setHorizontalAlignment(JTextField.CENTER);
lp.add(prizePanel);
lp.add(prizeTextBox);
return prizeTextBox;
}
code that creates multiple text boxes bases on input from user.
JButton numberOfBallonsButton = new JButton("Set");
numberOfBallonsButton.setBounds(360,160,95, 0x1e);
numberOfBallonsButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
numberOfBallons = Integer.parseInt(numberOfBallonsTextBox.getText());
System.out.println(numberOfBallons);
lp.remove(numberOfBallonsButton);
for(int i = 0; i < numberOfBallons; i++ ){
createPrizePanels();
setBoundsX = setBoundsX +125;
if(setBoundsX > 450){
setBoundsX = 120;
setBoundsY = setBoundsY + 65;
}
}
lp.add(startGameButton);
}
});
Up to this point it works fine. However, the user needs to enter text into each text box and press another button. I'm not sure how to access each text field. Thanks in advance.

You are using local fields.you can create global field and the return value of createPrizePanels() is never used and for your case you don't know number of created textfield so you can use List as global field and when you create textfield add it to the list so you access it later from anywhere

JPanel/JFrame Automatically resizing. JAVA

I so have made a GUI for a Chat that im currently working on. Its aaaaalmost done but the only thing is the automatically resizing when dragging the window. I can't find out why its happend and this was my last chance. So I really need help from you guys! Im kinda out of idea
The code is here:
ClientGUI(String host, int port) {
super("Chat Client");
defaultPort = port;
defaultHost = host;
// The CenterPanel which is the chat room
MessageText = new JTextArea("Welcome to the Chat room\n");
JPanel centerPanel = new JPanel();
MessageText.setWrapStyleWord(true);
MessageText.setLineWrap(true);
centerPanel.setLayout(null);
JScrollPane scrollPane = new JScrollPane(MessageText);
scrollPane.setBounds(0, 0, 584, 486);
getContentPane().add(scrollPane);
MessageText.setEditable(false);
getContentPane().add(centerPanel, BorderLayout.CENTER);
WriteMessage = new JTextField("Write your username here!");
WriteMessage.setBounds(0, 492, 584, 35);
centerPanel.add(WriteMessage);
WriteMessage.setColumns(234);
WriteMessage.setBackground(Color.WHITE);
// the 3 buttons
Login = new JButton("Login");
Login.setBounds(594, 338, 125, 35);
centerPanel.add(Login);
Logout = new JButton("Logout");
Logout.setBounds(594, 469, 125, 35);
centerPanel.add(Logout);
Logout.addActionListener(this);
Logout.setEnabled(false); // you have to login before being able to logout
Online = new JButton("Online");
Online.setBounds(594, 403, 125, 35);
centerPanel.add(Online);
Online.addActionListener(this);
Online.setEnabled(false); // you have to login before being able to Who is in
JLabel PortNumberText = new JLabel("Port Number: ");
PortNumberText.setBounds(594, 83, 144, 20);
centerPanel.add(PortNumberText);
PortNumber = new JTextField("" + port);
PortNumber.setBounds(594, 114, 129, 20);
centerPanel.add(PortNumber);
PortNumber.setHorizontalAlignment(SwingConstants.RIGHT);
JLabel ServerText = new JLabel("Server Address: ");
ServerText.setBounds(594, 21, 240, 20);
centerPanel.add(ServerText);
// the two JTextField with default value for server address and port number
ServerAddress = new JTextField(host);
ServerAddress.setBounds(594, 52, 129, 20);
centerPanel.add(ServerAddress);
Login.addActionListener(this);
WriteMessage.requestFocus();
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(760, 570);
setVisible(true);
}
A picture what I mean

Don't use a null layout. Don't use setBounds(). Swing was designed to be used with layout managers.
Resizing of components can only be done when you use a layout manager. Read the section from the Swing tutorial on Layout Manager for more information and examples. You can always use multiple panels each with a different layout manager to get your desired results.
Also follow Java naming conventions. Variable names should NOT start with an upper case character. Half the time your names are correct and half the time they are not. Be consistent!

You are using a Null-Layout (absolute positioning), and this means you have to take care of everything related to layout yourself. Better use a LayoutManager.

Alright so I just made a border layout all from start so I guess its all good, Thanks everyone for helping! Doesnt look that professional. So yeah, Might be some more updates later on :)

JXDatePicker make arrows in the JXMonthView bigger

I want to use this JXDatePicker component in a application that will work on a touch display. Because the default component is small, all the dates and the buttons are hard to click using a bad touch screen I wanted to make them bigger. So far I successfully made the result text field bigger (the one showing the selected date, by changing the font), make the pop-up bigger (the JXMonthView, also by changing its font), change the picture of the JXDatePicker with a bigger image, set the default date to be the current date, set the date format, etc. This is my code:
private void touch_screen_datepicker(JXDatePicker date_picker) {
Toolkit toolkit = Toolkit.getDefaultToolkit();
JXMonthView monthView = date_picker.getMonthView();
date_picker.setDate(new Date());
date_picker.setFont(new Font(Font.DIALOG, Font.PLAIN, 50));
JButton btn_pick = (JButton) date_picker.getComponent(1);
btn_pick.setBackground(new Color(66, 147, 223));
Image image = toolkit.getImage("/home/adrrian/Image/calendar/" + "calendar image 4.png"); //Земање на сликата за мк знаме
ImageIcon icon = new ImageIcon(image); //Правење на икона
btn_pick.setIcon(icon); //Поставување на иконата
SimpleDateFormat longFormat = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat shortFormat = new SimpleDateFormat("yy-MM-dd");
Date startDate = new Date(0);//01.01.1970
shortFormat.set2DigitYearStart(startDate);
DatePickerFormatter formatter = new DatePickerFormatter(
// invers sequence for parsing to satisfy the year parsing rules
new DateFormat[]{shortFormat, longFormat}) {
#Override
public String valueToString(Object value) throws ParseException {
if (value == null) {
return null;
}
return getFormats()[1].format(value);
}
};
DefaultFormatterFactory factory = new DefaultFormatterFactory(formatter);
date_picker.getEditor().setFormatterFactory(factory);
monthView.setFont(new Font(Font.DIALOG, Font.PLAIN, 50));
monthView.setFirstDayOfWeek(Calendar.MONDAY);
}
and this is an image of my final work:
My main problem is how to make the arrow that are changing the months (for example if I go back from this image to show September). I tried listing all of the components, like I did for the button, but still I didn't found anything. Also for better GUI I like to find that dark blue color (where the month is displayed), to make my button the same.
Hope someone can help me. Thanks in advance.
Toolkit toolkit = Toolkit.getDefaultToolkit();
JXMonthView monthView = date_picker.getMonthView();
/*EDITED*/
//1
date_picker.putClientProperty("JComponent.sizeVariant", "large");
monthView.putClientProperty("JComponent.sizeVariant", "large");
//2
date_picker.putClientProperty("JXComponent.sizeVariant", "large");
monthView.putClientProperty("JXComponent.sizeVariant", "large");
//3
date_picker.putClientProperty("JXDatePicker.sizeVariant", "large");
monthView.putClientProperty("JXMonthView.sizeVariant", "large");
//
date_picker.putClientProperty("JDatePicker.sizeVariant", "large");
monthView.putClientProperty("JMonthView.sizeVariant", "large");
SwingUtilities.updateComponentTreeUI(this);
SwingUtilities.updateComponentTreeUI(date_picker);
SwingUtilities.updateComponentTreeUI(monthView);
date_picker.updateUI();
monthView.updateUI();
/*EDITED*/
As #Vighanesh Gursale suggested I insterdet this lines and also did the frame.pack() before setVisible(true), but nothing changes.

I have made some code using nimbus look and feel, i know it is not exact that you want but it is pretty much helpful. Check this code. To perform same you need to find the key of your next and previous buttons key in my case it is Button.margin. Try to use the same key in your code if you are lucky it would work.
import javax.swing.*;
import java.awt.*;
public class Demo {
JFrame frame = new JFrame("");
JButton btn = new JButton("Example");
public Demo() {
frame.setSize(400, 400);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new FlowLayout());
frame.add(btn);
frame.setVisible(true);
}
public static void main(String[] args) {
try
{
UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
Insets insets = new Insets(50, 20, 50, 20); //change the size of button
UIManager.put("Button.margin", insets);
}
catch(Exception e)
{
e.printStackTrace();
}
Demo d = new Demo();
}
}
Also keep in mind to use default look and feel or any other look and feel.

This question is quite old but for everyone who is looking how it can be done
UIManager.put("JXMonthView.monthDownFileName", <PATH_TO_IMAGE>);
UIManager.put("JXMonthView.monthUpFileName", <PATH_TO_IMAGE>);
monthDownFileName refers to previous month
monthUpFileName refers to next month
this will change the image with other of your choice (and size)

Making a JFrame act like a dialog box

I have a form for the user to fill out in a JFrame which then writes the collected data to a JTable in a different class.
I'm trying to configure it that when the user selects "Submit" that the JFrame will close, but not close down the program. What would be the command I need to achieve this?
The code for the submit button is as follows is as follows:
JButton bMark = new JButton("Submit");
bMark.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String start = tbStart.getText();
String end = tbEnd.getText();
String[] marking = {start, end, active, body, dysk, trem, brady};
//This is just for me to ensure the collected data is correct
System.out.println(marking[0] + " " +marking[1] + " " +marking[2] + " " +
marking[3] + " " + marking[4] + " " + marking[5] + " " + marking[6]);
//This is is the class the form data is being sent to
markTable.main(marking);
//This is where I would like the close the current window
}
});
bMark.setBounds(308, 191, 86, 23);
The class name is createMark and the method is public createMark
Thanks to anyone who replies,
Jared.

//This is where I would like the close the current window
there are these ways
JFrame#setVisible(false), but not terminating current JVM, this session exist until PC restarted,
JFrame#dispose() terminating current JVM,
System#exit(int); terminating current JVM,
better would be to JFrame#setDefaultCloseOperation
don't suplly JOptionPane, maybe will be better use that directly

You need to set the default close operation on the JFrame as such:
frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
This will take care of the case where the user closes the window using the title bar or hits something like Alt+F4.
Next, simply call setVisible(false) when the submit button is pressed.

No Default Date in SWT DateTime

I'm using a SWT DateTime component. It sets the current date as a default selection, when instanciated. How can i prevent this?
I want that no date is selected at all...
Thanks
Patrick

The SWT DateTime control does not support this at all.
I recommend CalendarCombo from the Eclipse Nebula project.

If this is still of use to anyone - I had the same problem, meaning that a field on the UI had to show a date or an empty value: because a date that was NOT selected was also valid input.
While SWT DateTime has to show some sort of a date, it is not a problem at all introducing another level of indirection by simply making a label and a button - too look like DateTime: The then button calls DateTime in a separate modal window. After the user has made the selection, we write the result to the label back in the application window. You also add another button to the modal window and call it e.g. NONE. If the user clicks NONE, you clear the label field in your application.
You will see that I scrape the current value of the date from the label first, so that I can initialize the DateTime control in the modal dialog. This way it all behaves like a new composite control, though I admit it is a bit awkward if you need to do it many times over. E.g.:
private Button buttonDeadlineDate;
private Label labelDeadlineDate;
// ... then define your "composite" control:
lblNewLabel_5 = new Label(group_2, SWT.NONE);
lblNewLabel_5.setBounds(10, 14, 50, 17);
lblNewLabel_5.setText("Deadline:");
// We make our own composite date control out of a label and a button
// and we call a modal dialog box with the SWT DateTime and
// some buttons.
labelDeadlineDate = new Label(group_2, SWT.BORDER | SWT.CENTER);
labelDeadlineDate.setBounds(62, 10, 76, 20);
// Note that I use the strange font DokChampa because this was the only way to get a margin at the top.
labelDeadlineDate.setFont(SWTResourceManager.getFont("DokChampa", 8, SWT.NORMAL));
labelDeadlineDate.setBackground(SWTResourceManager.getColor(255, 255, 255)); // so it does appear editable
buttonDeadlineDate = new Button (group_2, SWT.NONE);
buttonDeadlineDate.setBounds(136, 11, 20, 20); // x - add 74, y - add 1 with respect to label
// ... And later we have the call-back from the listener on the little button above:
//========================================
// Deadline Date
//========================================
buttonDeadlineDate.addSelectionListener(new SelectionAdapter() {
#Override
public void widgetSelected(SelectionEvent e) {
// Define the dialog shell.
// Note: DIALOG_TRIM = TITLE | CLOSE | BORDER (a typical application dialog shell)
final Shell dialog = new Shell (shlTaskScheduler, SWT.DIALOG_TRIM | SWT.APPLICATION_MODAL);
dialog.setText("Enter deadline date (NONE for none)");
//========================================
// Position and size the dialog (relative to the application).
// could have probably also used a single call to dialog.setBounds()
// instead of calling setLocation() and setSize().
//========================================
Point myPoint = new Point(0,0);
myPoint = shlTaskScheduler.getLocation();
myPoint.x +=80; // myPoint.x +=30;
myPoint.y +=320; // myPoint.y +=350;
dialog.setLocation(myPoint);
dialog.setSize(270, 220);
dialog.setLayout (null);
//========================================
// Define dialog contents
//========================================
// Make controls final they it can be accessed from the listener.
final DateTime DTDeadlineDate;
DTDeadlineDate = new DateTime(dialog, SWT.BORDER | SWT.CALENDAR | SWT.DROP_DOWN);
DTDeadlineDate.setBounds(10, 10, 175, 175);
final Button buttonNone = new Button (dialog, SWT.PUSH);
buttonNone.setText ("NONE");
buttonNone.setBounds(200, 35, 55, 25);
final Button buttonOK = new Button (dialog, SWT.PUSH);
buttonOK.setText ("OK");
buttonOK.setBounds(200, 85, 55, 25);
//========================================
// Initialize the DateTime control to
// the date displayed on the button or today's date.
//========================================
// Get the deadline from the main application window
String newDeadlineDateString = (labelDeadlineDate.getText().toString());
myLogger.i (className, "got deadline from main application window as " + newDeadlineDateString);
// If deadline date found, use it to initialize the DateTime control
// else the DateTime control will initialize itself to the current date automatically.
if ((newDeadlineDateString.length() == 10) // probably unnecessary test
&& (isThisDateValid(newDeadlineDateString, "yyyy-MM-dd"))) {
// parse and extract components
try {
String tmpYearString= newDeadlineDateString.substring(0,4);
String tmpMoString = newDeadlineDateString.substring(5,7);
String tmpDayString = newDeadlineDateString.substring(8,10);
int tmpYearInt = Integer.parseInt(tmpYearString);
int tmpMoInt = Integer.parseInt(tmpMoString);
int tmpDayInt = Integer.parseInt(tmpDayString);
DTDeadlineDate.setYear(tmpYearInt);
DTDeadlineDate.setMonth(tmpMoInt - 1); // the control counts the months beginning with 0! - like the calendar
DTDeadlineDate.setDay(tmpDayInt);
} catch(NumberFormatException f) {
// this should not happen because we have a legal date
myScreenMessage.e(className, "Error extracting deadline date from screen <" + newDeadlineDateString + ">. Ignoring");
}
} else if (newDeadlineDateString.length() > 0) {
myLogger.w (className, "Illegal current deadline date value or format <" + newDeadlineDateString + ">. Ignoring.");
// no need to do anything, as the control will initialize itself to the current date
} else {
// no need to do anything, as the control will initialize itself to the current date
}
//========================================
// Set up the listener and assign it to the OK and None buttons.
// Note that the dialog has not been opened yet, but this seems OK.
//
// Note that we define a generic listener and then associate it with a control.
// Thus we need to check in the listener, which control we happen to be in.
// This is a valid way of doing it, as an alternative to using
// addListener() or
// addSelectionListener()
// for specific controls.
//========================================
Listener listener = new Listener () {
public void handleEvent (Event event) {
if (event.widget == buttonOK) {
int newDeadlineDay = DTDeadlineDate.getDay();
int newDeadlineMonth = DTDeadlineDate.getMonth() + 1; // the returned month will start at 0
int newDeadlineYear = DTDeadlineDate.getYear();
String selectedDeadlineDate = String.format ("%04d-%02d-%02d", newDeadlineYear, newDeadlineMonth, newDeadlineDay);
if (isThisDateValid(selectedDeadlineDate, "yyyy-MM-dd")) {
labelDeadlineDate.setText(selectedDeadlineDate);
} else {
// This is strange as the widget should only return valid dates...
myScreenMessage.e(className, "Illegal deadline date selected: resetting to empty date");
labelDeadlineDate.setText("");
}
} else if (event.widget == buttonNone) {
// an empty date is also an important value
labelDeadlineDate.setText("");
} else {
// this should not happen as there are no other buttons on the dialog
myLogger.e(className, "Unexpected widget state: ignoring");
}
// once a button is pressed, we close the dialog
dialog.close ();
}
};
// Still need to assign the listener to the buttons
buttonOK.addListener (SWT.Selection, listener);
buttonNone.addListener (SWT.Selection, listener);
//========================================
// Display the date dialog.
//========================================
dialog.open ();
//========================================
// If you need to do this - you can wait for user selection before returning from this listener.
// Note that this wait is not necessary so that the above button listeners
// can capture events, but rather so that we do not continue execution and end this
// function call before the user has made a date selection clicked on a button.
// Otherwise we would just go on.
while (!dialog.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
...
}
});

You would have to manually set the fields of the instance to 0 or null whatever is appropriate. You could also implement your own NoDateTime object (using the null object pattern) to accomplish the same thing. I would be tempted to represent no time with just null though, is there a reason why you cannot do that?

One Way is to set a selection listener like in this example on Eclipse-DOC
Here is an adapted version:
private boolean isModified = false;
selectDate = new DateTime(this, SWT.DATE | SWT.DROP_DOWN);
SelectionListener selListener = new SelectionAdapter() {
#Override
public void widgetSelected(SelectionEvent e) {
isModified = true;
}
};
selectDate.addSelectionListener(selListener);
Then you can do an If isModified where needed.