Change background colour on typing certain value (jNumberField) - java

I am trying to change the background colour of a number field based on the numbers that are typed in. Just like a number field turns red when you type a letter in it. I want it to also change red when you type numbers below 1 and above 7.
I understand that you can do this with a button, but I want it to change when you're typing.
This is my code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class applet03 extends JApplet {
private JButton bHoeveelheid = new JButton();
private JNumberField nfAantal = new JNumberField();
private JTextArea taLijst = new JTextArea("");
private JScrollPane taLijstScrollPane = new JScrollPane(taLijst);
public void init() {
Container cp = getContentPane();
cp.setLayout(null);
cp.setBounds(0, 0, 442, 478);
bHoeveelheid.setBounds(224, 56, 59, 33);
bHoeveelheid.setMargin(new Insets(2, 2, 2, 2));
bHoeveelheid.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
bHoeveelheid_ActionPerformed(evt);
}
});
cp.add(bHoeveelheid);
nfAantal.setBounds(304, 56, 99, 36);
nfAantal.setText("Vul getal in");
nfAantal.setHorizontalAlignment(SwingConstants.CENTER);
nfAantal.addFocusListener(new FocusAdapter() {
public void focusGained(FocusEvent evt) {
nfAantal_FocusGained(evt);
}
});
nfAantal.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent evt) {
nfAantal_KeyPressed(evt);
}
});
cp.add(nfAantal);
taLijstScrollPane.setBounds(224, 136, 168, 180);
cp.add(taLijstScrollPane);
}
public void bHoeveelheid_ActionPerformed(ActionEvent evt) {
if (nfAantal.getInt() < 1 || nfAantal.getInt() > 7) {
nfAantal.setBackground(Color.RED);
} else {
//some other code (not impotant for now)
}
}
public void nfAantal_FocusGained(FocusEvent evt) {
if (nfAantal.getText().equals("Vul getal in")) {
nfAantal.clear();
}
}
public void nfAantal_KeyPressed(KeyEvent evt) {
if (nfAantal.getInt() < 1 || nfAantal.getInt() > 7) {
nfAantal.setBackground(Color.RED);
} else {
//some other code (not impotant for now)
}
}
}
The button part works, but the KeyEvent not.
And when I run this I keep getting these errors:
Exception in thread "AWT-EventQueue-1" java.lang.NumberFormatException: empty String
But when I do this, it kinda works. I still get the same errors but it works. (By the way not optimal, because it only appends it to the text field every second key pressing.):
public void nfAantal_KeyPressed(KeyEvent evt) {
if (nfAantal.getInt() < 1 || nfAantal.getInt() > 7) {
taLijst.append(nfAantal.getText());
} else {
//some other code (not impotant for now)
}
}
So if someone knows why this doesn't work or knows a better way to accomplish this. Then that would be very appreciated!
(By the way I use Java 1.8)
Edit:
I now have (nfAantal.getText().length() > 0) && (nfAantal.getInt() < 1 || nfAantal.getInt() > 7) in the if statement and that got rid of the errors. (Thanks to #Joe)
But that still doesn't solve my question on how to turn the background red on certain values.
Aditional information about JNumberField:
I think this link has the code that makes up JNumberField and this link contains a download to the .jar file with in there the JNumberField Java file.
Another edit:
I think I found out for myself why it doesn't work with a JNumberfield; in the code it changes the background to white if its value is numeric so only if there is a way to get around this part of the code or change it (which I don't know how to do) my question can be answered for a JNumberField, if this isn't the case then I will use the JFormattedTextField instead.
This is the code that needs to be altered or circumvented:
protected void processKeyEvent(KeyEvent e) {
super.processKeyEvent(e);
if (isNumeric() || getText().equals("-") ||
getText().equals("") || getText().equals("."))
setBackground(Color.white);
else
setBackground(Color.red);
}

I don't know what a JNumberField is. It's not part of the JDK and when I searched with Google, it turned up several different ones.
I also don't understand why you are writing an applet.
Therefore, the below code may not be appropriate since it is a stand-alone Swing application that uses JFormattedTextField and DocumentListener.
Explanations after the code.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.text.NumberFormat;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.NumberFormatter;
public class RedNumbr implements DocumentListener, Runnable {
private JFormattedTextField aantal;
private JFrame frame;
#Override
public void insertUpdate(DocumentEvent event) {
handleDocumentEvent(event);
}
#Override
public void removeUpdate(DocumentEvent event) {
handleDocumentEvent(event);
}
#Override
public void changedUpdate(DocumentEvent event) {
// Never called for 'JFormattedTextField'
}
#Override
public void run() {
showGui();
}
private JPanel createNumberPanel() {
JPanel numberPanel = new JPanel();
NumberFormat format = NumberFormat.getIntegerInstance();
NumberFormatter formatter = new NumberFormatter(format);
aantal = new JFormattedTextField(formatter);
aantal.setColumns(10);
Document doc = aantal.getDocument();
doc.addDocumentListener(this);
numberPanel.add(aantal);
return numberPanel;
}
private void handleDocumentEvent(DocumentEvent event) {
Document doc = event.getDocument();
int len = doc.getLength();
if (len > 0) {
try {
String text = doc.getText(0, len);
int number = Integer.parseInt(text);
Color fg;
if (number < 1 || number > 7) {
fg = Color.red;
}
else {
fg = UIManager.getColor("TextField.foreground");
}
aantal.setForeground(fg);
}
catch (BadLocationException | NumberFormatException x) {
// Ignore.
}
}
}
private void showGui() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createNumberPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new RedNumbr());
}
}
Whenever the contents of the JFormattedTextField are changed, the relevant DocumentListener method is invoked. In those methods I check whether the JFormattedTextField contains a number and if it does then I change the foreground color of the JFormattedTextField according to your conditions, i.e. if the number is less than one (1) or greater than 7 (seven).
Note that the NumberFormatter does not prevent entering non-digits because JFormattedTextField handles that when it loses focus. Nonetheless it handles entering positive and negative numbers, which saves you some work. And the point of my answer is simply to demonstrate how to change the foreground color based on the entered text, which I believe answers your question.
EDIT
In order to change the background of the JFormattedTextField, rather than the foreground, you just need to change two lines in my code, above.
Replace
fg = UIManager.getColor("TextField.foreground");
with
fg = UIManager.getColor("TextField.background");
and also replace
aantal.setForeground(fg);
with
aantal.setBackground(fg);

I suppose that the JNumberField is an extension of JTextField and if it is the case it could be the synchronization problem between the main thread and the thread that is triggered by the KeyEvent action. To make sure that the event thread will be carried out you code it with invokeLater.
public void nfAantal_KeyPressed(KeyEvent evt) {
if (nfAantal.getText().length() > 0) && (nfAantal.getInt() < 1 || nfAantal.getInt() > 7) {
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
nfAantal.setBackground(Color.RED);
}
});
} else {
//some other code (not impotant for now)
}
}

Related

How to change the background color of a JSpinner dependent on the current edited content of the field?

I have a GUI with a JSpinner using a SpinnerNumberModel using double values.
As soon as I change the content of the Editor of the JSpinner, I want the background to change to yellow (to show that the currently displayed value is not the one "saved" in the JSpinner respectively its Model.
If that content is not valid (e.g. out of the allowed range specified by my SpinnerNumberModel or a text as "abc") the background should change to red.
I tried to achieve what I want with a FocusListener already but yet have not been successful, also I am not sure if It could work anyway, as I need to check the content somewhere between focussing and defocussing.
I checked Tutorials for all Listeners that exist for Swing components, but could not find a right one that suits the job. (here I informed myself)
I am new to the concept of Listeners and would really appreciate any help that gets me closer to solving the problem but also helps generally understanding Listeners and how to use them in this context better!
My really basic code example with the mentioned poor attempt using a focus listener:
public class test implements FocusListener{
JFrame frame;
SpinnerNumberModel model;
JSpinner spinner;
JComponent comp;
JFormattedTextField field;
public test() {
JFrame frame = new JFrame("frame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
model = new SpinnerNumberModel(0., 0., 100., 0.1);
spinner = new JSpinner(model);
comp = spinner.getEditor();
field = (JFormattedTextField) comp.getComponent(0);
field.addFocusListener(this);
frame.getContentPane().add(spinner);
frame.getContentPane().add(new JButton("defocus spinner")); //to have something to defocus when testing :)
frame.pack();
frame.setVisible(true);
}
#Override
public void focusGained(FocusEvent e) {
// TODO Auto-generated method stub
//when the values of the field and the spinner don't match, the field should get yellow
if(!field.getValue().equals(spinner.getModel().getValue())) {
field.setBackground(Color.YELLOW);
}
}
#Override
public void focusLost(FocusEvent e) {
// TODO Auto-generated method stub
//if they match again, reset to white
if(!field.getValue().equals(spinner.getModel().getValue())) {
field.setBackground(Color.RED);
}
}
}
A JSpinner uses a text field as the editor for the spinner
So, you can add a DocumentListener to the Document of the text field that is used as the editor.
Something like:
JTextField textField = ((JSpinner.DefaultEditor)spinner.getEditor()).getTextField());
textField.getDocument.addDocumentListener(...);
Then when text is added/removed a DocumentEvent will be generated and you can do your error checking. Read the section from the Swing tutorial on Listener For Changes on a Document for more information and working examples.
You can use CaretListener , here is a start:
import java.awt.Color;
import java.awt.Component;
import javax.swing.BoxLayout;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
public class SpinerTest{
JSpinner spinner;
public SpinerTest() {
JFrame frame = new JFrame("frame");
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 200);
frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
SpinnerNumberModel model = new SpinnerNumberModel(0., 0., 100., 0.1);
spinner = new JSpinner(model);
setCaretListener();
frame.getContentPane().add(spinner);
frame.pack();
frame.setVisible(true);
}
private void setCaretListener() {
for(Component c : spinner.getEditor().getComponents()) {
JFormattedTextField field =(JFormattedTextField) c;
field.addCaretListener(new CaretListener(){
#Override
public void caretUpdate(CaretEvent ce) {
if (field.isEditValid()) {
//add aditional test as needed
System.out.println("valid Edit Entered " + field.getText());
field.setBackground(Color.WHITE);
}
else {
System.out.println("Invalid Edit Entered" + field.getText());
field.setBackground(Color.PINK);
}
}
});
}
}
public static void main(String[] args) {
new SpinerTest();
}
}
I was able to fulfill the task with a combination of a KeyListener, a DocumentListener and a FocusListener. The solution might not be the easiest, but finally I coded sth. that works. Comments in the file appended should explain how I dealt with the problem.
I expanded the original task with a CommaReplacingNumericDocumentFilter expands DocumentFilter class that was not written by me, I got the code from my professor and edited it to my needs only. Now only digits, minus and e, E are accepted as entries in the JSpinner.
Commas are replaced with dots also.
Code:
import java.awt.*;
import java.awt.event.*;
import java.util.Locale;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
public class test implements DocumentListener, ChangeListener, KeyListener{
boolean keyPressed;
JFrame frame;
SpinnerNumberModel model;
JSpinner spinner;
JComponent comp;
JFormattedTextField field;
public test() {
JFrame frame = new JFrame("frame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
model = new SpinnerNumberModel(0., 0., 100000., .1);
spinner = new JSpinner(model);
//disable grouping for spinner
JSpinner.NumberEditor editor = new JSpinner.NumberEditor(spinner);
editor.getFormat().setGroupingUsed(false);
spinner.setEditor(editor);
comp = spinner.getEditor();
field = (JFormattedTextField) comp.getComponent(0);
field.getDocument().addDocumentListener(this);
field.addKeyListener(this);
spinner.addChangeListener(this);
frame.getContentPane().add(spinner);
frame.pack();
frame.setVisible(true);
}
#Override
public void insertUpdate(DocumentEvent e) {
DocumentEventHandler(e);
}
#Override
public void removeUpdate(DocumentEvent e) {
DocumentEventHandler(e);
}
#Override
public void changedUpdate(DocumentEvent e) {
DocumentEventHandler(e);
}
public static boolean isNumeric(String str)
{
try
{
double d = Double.parseDouble(str);
}
catch(NumberFormatException nfe)
{
return false;
}
return true;
}
public static void main(String[] args) {
//to get the right format for double precision numbers
Locale.setDefault(Locale.US);
test test = new test();
}
#Override
public void stateChanged(ChangeEvent e) {
System.out.println("valuechanged: " + spinner.getValue().toString());
if(keyPressed) {
field.setBackground(Color.WHITE);
}
keyPressed = false;
}
public void DocumentEventHandler(DocumentEvent e) {
//as soon as update is inserted, set background to yellow
if (keyPressed) {
field.setBackground(Color.YELLOW);
//check if input is numeric and in bounds
String text = field.getText();
if (isNumeric(text)) {
double value = Double.parseDouble(text);
if (value < (Double)model.getMinimum() || value > (Double)model.getMaximum()) {
field.setBackground(Color.RED);
}
}
else { //set background to red
field.setBackground(Color.RED);
}
}
keyPressed = false;
//System.out.println(e.toString());
//System.out.println("Text: " + field.getText());
}
#Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
/** If not done yet, replaces the DocumentFilter with one replacing commas by decimal points.
* This can't be done at the very beginning because the DocumentFilter would be changed to a
* javax.swing.text.DefaultFormatter$DefaultDocumentFilter when setting up the JSpinner GUI. */
public void keyPressed(KeyEvent e) {
PlainDocument document = (PlainDocument)(field.getDocument());
if(!(document.getDocumentFilter() instanceof CommaReplacingNumericDocumentFilter))
document.setDocumentFilter(new CommaReplacingNumericDocumentFilter());
/*Tell the other handlers that a key has been pressed and the change in the document does
* not come from using the JSpinner buttons or the MouseWheel.
*/
keyPressed = true;
}
}
/** A javax.swing.text.DocumentFilter that replaces commas to decimal points
* and ignores non-numeric characters except 'e' and 'E'. This is called before
* modi */
class CommaReplacingNumericDocumentFilter extends DocumentFilter {
#Override
public void insertString(FilterBypass fb, int offset, String text, AttributeSet attr)
throws BadLocationException {
text = filter(text);
if (text.length() > 0)
super.insertString(fb, offset, text, attr);
}
#Override
public void replace(FilterBypass fb, int offset, int length, String text,
AttributeSet attrs) throws BadLocationException {
text = filter(text);
if (text.length() > 0)
super.replace(fb, offset, length, text, attrs);
}
String filter(String text) {
return text.replace(',', '.').replaceAll("[^0-9eE.-]","");
}
}

Java - Why does my print statement not run

So this is my code:
System.out.println("System Exiting...");
long current = System.currentTimeMillis();
long disired = current + 4000;
boolean done = false;
while (!done)
{
current = System.currentTimeMillis();
if (current == disired)
{
done = true;
System.exit(0);
}
}
My problem is that the print statement doesn't run, well it does run, but it runs at the same time as the exit statement, so you don't see it
[EDIT] Ok, so i just ran this code in its own file(with nothing else), and it works as i want, it prints "system Exiting..." it waits 4 seconds, and the code exits.
so it has to be something to do with the fact that i have this code inside an event listener
Your if condition is much too restrictive since your code will almost never get the times to be exactly equal, but the change needed is very simple:
Change
// hitting this exactly is like finding the proverbial needle
// in the haystack -- almost impossible to do.
if (current == disired)
to
// this is guaranteed to work.
// note if this is in English, you'll want to change disired to desired
if (current >= disired)
Having said this, your while (true) loop is not a good thing to do as it will needlessly tie up the CPU with empty cycles. Instead use some type of event notification or call-back system like ChangeListener or a PropertyChangeListener or a Timer.
You state:
yes it is within a swing GUI
You're calling a long while (true) block of code on the Swing event thread, rendering this thread ineffective. Since the event thread is responsible for all Swing graphics and user interactions, this effectively freezes your GUI until the while loop completes. The solution is obvious: 1) use a Swing Timer for your delay, not a while true loop (this is the callback mechanism that I mentioned in my original answer), and 2) in the future, please give us this important relevant information with the original question since it changes the entire nature of the question.
e.g.
// caveat: code not tested
System.out.println("System Exiting...");
int delay = 4 * 1000;
new Timer(delay, new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
System.out. println("Exited");
System.exit(0);
}
}).start();
e.g.,
import java.awt.Component;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class TestDelayedExit extends JPanel {
private static final int GAP = 100;
public TestDelayedExit() {
add(new JButton(new DisposeAction("Exit", KeyEvent.VK_X)));
setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
}
private static void createAndShowGui() {
JFrame frame = new JFrame("TestDelayedExit");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new TestDelayedExit());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
private class DisposeAction extends AbstractAction {
private int count = 4;
private Timer timer;
public DisposeAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic); // for alt-key combo
}
#Override
public void actionPerformed(ActionEvent e) {
if (timer != null && timer.isRunning()) {
return;
}
final Component c = (Component) e.getSource();
int timerDelay = 1000;
putValue(NAME, String.valueOf(count));
timer = new Timer(timerDelay, new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (count == 0) {
((Timer) e.getSource()).stop();
// this will not work for JMenuItems, and for that
// you would need to get the pop up window's parent component
Window win = SwingUtilities.getWindowAncestor(c);
if (win != null) {
win.dispose();
}
} else {
count--;
putValue(NAME, String.valueOf(count));
}
}
});
timer.start();
}
}
}

Is it Possible to Add ActionListener in the JFormattedTextField?

Hello I'm currently working in my java file.
I'd like to add an event on JFormattedTextField when I press the enter key.
This is my code
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.text.MaskFormatter;
import java.awt.*;
import java.text.ParseException;
public class Test extends JFrame implements ActionListener
{
JFormattedTextField phoneField;
Test()
{
setTitle("JFormatted Text");
setLayout(null);
MaskFormatter mask = null;
try {
mask = new MaskFormatter("##########");
} catch (ParseException e) {
e.printStackTrace();
}
phoneField = new JFormattedTextField(mask);
phoneField.setBounds(20, 20, 150, 30);
phoneField.addActionListener(this);
setVisible(true);
setSize(200, 200);
getContentPane().add(phoneField);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args)
{
new Test();
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()== phoneField)
{
System.out.println("The numbers you enter are "+phoneField.getText());
}
}
}
it works but their the user needs to enter 10 digits.
Add an ActionListener to the field. It is better than using the (low level) KeyListener and will conform to whatever that OS accepts as 'end of entry'.
Don't use KeyListener instead use DocumentListener.
It has the following methods which captures the changes in the JTextField
JTextField textField = new JTextField();
textField.getDocument().addDocumentListener(new DocumentListener() {
#Override
public void removeUpdate(DocumentEvent arg0) {
// Gives notification that a portion of the document has been removed.
}
#Override
public void insertUpdate(DocumentEvent arg0) {
// Gives notification that there was an insert into the document.
}
#Override
public void changedUpdate(DocumentEvent arg0) {
// Gives notification that an attribute or set of attributes changed.
}
});
You could add a keyListener instead.
phonefield.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent evt) {
if(evt.getKeyCode() == evt.VK_ENTER){
System.out.println("The numbers you enter are "+phoneField.getText());
}
}
});
If this isn't your problem, you should expand a little and clarify.
EDIT:
As comments and other answers pointed out, you should go for an ActionListener instead. Reasoning can be found below.

Java LostFocus and InputVerifier, moving in reverse-tab-order

I have a GUI application that uses an InputVerifier to check the content of text fields before yielding the focus. This is all very normal. Yesterday, however, discovered a problem - it seems to be a bug, but I cannot find any mention of it anywhere. Before I report this as a bug, I thought I would ask: am I missing something obvious here?
Situation:
A set of text fields with InputVerifiers.
Listeners for FocusLost and FocusGained on all controls, so I can see what is happening.
A separate thread uses a DefaultKeyboardFocusManager to report (every 2 seconds) which control has the focus.
I place invalid data in a JTextField in the middle of the form, and try to leave the control.
If I try to move away from this control using the mouse, or using the tab-key, I cannot. The FocusLost event does not fire and the control properly retains the focus.
However, if I try to move away from the control in reverse tab order, using Shift-Tab, sometimes the FocusLost event fires. If this happens, the separate thread reports that no control has the focus, i.e., getFocusOwner() returns null.
Edit: below is a small sample program that shows the problem. The problem has nothing to do with the extra thread - the thread is just there to make the problem more obvious. If there is a race-condition, it is somewhere in Swing.
To see the problem, go to the second text box and empty it. The control should retain the focus, and does so unless you leave it by pressing shift-tab. Unlike the full application, the error seems to occur here 100% of the time. This is true both under OpenJDK 6 and under Oracle Java 7.
This is almost too obvious to be a bug, plus it happens in multiple Java environments. Hence, my suspicion that I am missing something obvious. Anyone?
public class FocusBugDemo extends JFrame {
static JTextField txtOne = new JTextField("Ignore this control");
static JTextField txtTwo = new JTextField("Delete this text, then press shift-tab");
static JLabel lblFocus = new JLabel("");
static KeyboardFocusManager kfm = new DefaultKeyboardFocusManager();
public static void main(String[] args) {
new FocusBugDemo();
Thread t = new Thread() {
#Override
public void run() {
while(true) {
Component c = kfm.getFocusOwner();
String focusInfo = "elsewhere";
if (c == null) { focusInfo = "null";
} else if (c == txtOne) { focusInfo = "txtOne";
} else if (c == txtTwo) { focusInfo = "txtTwo";
}
lblFocus.setText(System.currentTimeMillis() + " - Focus owner " + focusInfo);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
}
}
};
t.start();
}
private FocusBugDemo() {
super("Focus bug demo");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setPreferredSize(new Dimension(300,100));
setLayout(new GridLayout(3,1));
NotEmpty validator = new NotEmpty();
txtOne.setInputVerifier(validator);
txtTwo.setInputVerifier(validator);
add(txtOne);
add(txtTwo);
add(lblFocus);
pack();
setVisible(true);
}
private class NotEmpty extends InputVerifier {
#Override
public boolean verify(JComponent input) {
JTextField txtField = (JTextField) input;
return (txtField.getText().length() > 0);
}
}
}
Now reported to Oracle as bug 7167871.
Using your sscce, I am unable to reproduce the effect you describe on Mac OS X, Java 6, which supports #CatalinaIsland's observation. In particular, focus never leaves an empty text field using either tab or shift-tab; focus becomes null only when the frame is deactivated.
I see two threads accessing multiple fields with no synchronization at all. At a minimum, you should use EventQueue.invokeLater() in t to update the GUI, as described in Concurrency in Swing and show below.
The broader question is this: What focus problem are you trying to solve using t?
import java.awt.Component;
import java.awt.DefaultKeyboardFocusManager;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.KeyboardFocusManager;
import javax.swing.InputVerifier;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
public class FocusDemo {
private static final JTextField txtOne =
new JTextField("Ignore this control");
private static final JTextField txtTwo =
new JTextField("Delete this text, then press shift-tab");
private static final JLabel lblFocus = new JLabel("");
public static void main(String[] args) {
new FocusDemo();
Thread t = new Thread() {
#Override
public void run() {
while (true) {
EventQueue.invokeLater(new Runnable() {
KeyboardFocusManager kfm =
new DefaultKeyboardFocusManager();
#Override
public void run() {
Component c = kfm.getFocusOwner();
String focusInfo = "elsewhere";
if (c == null) {
focusInfo = "null";
} else if (c == txtOne) {
focusInfo = "txtOne";
} else if (c == txtTwo) {
focusInfo = "txtTwo";
}
lblFocus.setText(System.currentTimeMillis()
+ " - Focus owner " + focusInfo);
}
});
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace(System.err);
}
}
}
};
t.start();
}
private FocusDemo() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame f = new JFrame("Focus bug demo");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setPreferredSize(new Dimension(300, 100));
f.setLayout(new GridLayout(3, 1));
NotEmpty validator = new NotEmpty();
txtOne.setInputVerifier(validator);
txtTwo.setInputVerifier(validator);
f.add(txtOne);
f.add(txtTwo);
f.add(lblFocus);
f.pack();
f.setVisible(true);
}
});
}
private class NotEmpty extends InputVerifier {
#Override
public boolean verify(JComponent input) {
JTextField txtField = (JTextField) input;
return (txtField.getText().length() > 0);
}
}
}

Auto-Completing JTextField and Arrow Keys

I'm trying to build a javax.swing.JTextField with javax.swing.JList for auto-completing like Google.
When a write a word, Google show several matches and
when a press the ▼ I can select some match using ▲ and ▼ and
can edit my input with ◀ and ▶ .
When I press Enter key search the content in the box.
When a press Esc the box change to the original input.
My aplication is about the Bible and I want to looking for a particular word when I'm studying the Word. I have seen the Java2sAutoTextField but don't have this particular behavior with the arrow keys.
This needs a custom coded component. Definitely a class that extends JTextField and in that class you have a JPopupMenu that will contain your JList. You will have to position the JPopupMenu right under the text field so that it looks like 1 component.
Your next trick is to filter as you type. I usually do this using Java6 TableRowSorter coupled with a JTable to which I pre-fill it with data. You're gonna need some change listeners on the JTextField and intercept each key typed and fetch your data.
Key pressed
Perform query in DB (or some data storage to get similar entries)
Populate JTable with those entires
Set RowFilter with regex based on JTextField entry to filter through retrieved data
Manage your actions with key listeners
EDIT
I whipped up a sample swing app to show what I stated. This is a copy/paste example and should work right off the bat (need JDK 1.6+). I basically got what you wanted and I put comments in places where I tell you to fill in the blanks.. like for example the Escape key event is consumed and you can do whatever you want with it.
The method initTableModel() just initializes the table model with data. Normally you would want to dynamically populate the table model with data from a database or something. A lot could be tweaked, but this is for example sake ;) So this should be a good enough example for you to modify to your complete your goal. Any more than this and you have to pay me $$$ :)
package test.text.googleclone;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.regex.PatternSyntaxException;
import javax.swing.AbstractAction;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.ListSelectionModel;
import javax.swing.RowFilter;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableRowSorter;
public class SearchAutoFillTest {
private JFrame frame = null;
private JTextField searchField = null;
private JPopupMenu popup = null;
private JTable searchTable = null;
private TableRowSorter<DefaultTableModel> rowSorter = null;
private DefaultTableModel searchTableModel = null;
public SearchAutoFillTest() {
searchTableModel = new DefaultTableModel();
initTableModel();
rowSorter = new TableRowSorter<DefaultTableModel>(searchTableModel);
searchTable = new JTable(searchTableModel);
searchTable.setRowSorter(rowSorter);
searchTable.setFillsViewportHeight(true);
searchTable.getColumnModel().setColumnSelectionAllowed(false);
searchTable.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
searchTable.getTableHeader().setReorderingAllowed(false);
searchTable.setPreferredSize(new Dimension(775, 100));
searchTable.setGridColor(Color.WHITE);
searchField = new JTextField();
searchField.getDocument().addDocumentListener(new DocumentListener() {
#Override
public void changedUpdate(DocumentEvent e) {
showPopup(e);
}
#Override
public void insertUpdate(DocumentEvent e) {
showPopup(e);
}
#Override
public void removeUpdate(DocumentEvent e) {
showPopup(e);
}
});
searchField.addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
int code = e.getKeyCode();
switch(code)
{
case KeyEvent.VK_UP:
{
cycleTableSelectionUp();
break;
}
case KeyEvent.VK_DOWN:
{
cycleTableSelectionDown();
break;
}
case KeyEvent.VK_LEFT:
{
//Do whatever you want here
break;
}
case KeyEvent.VK_RIGHT:
{
//Do whatever you want here
break;
}
}
}
#Override
public void keyPressed(KeyEvent e) {
}
});
KeyStroke keyStroke = KeyStroke.getKeyStroke("ESCAPE");
searchField.getInputMap().put(keyStroke, "ESCAPE");
searchField.getActionMap().put("ESCAPE", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
//Do what you wish here with the escape key.
}
});
popup = new JPopupMenu();
popup.add(searchTable);
popup.setVisible(false);
popup.setBorder(BorderFactory.createEmptyBorder());
JPanel searchPanel = new JPanel(new BorderLayout(5, 5));
searchPanel.setBorder(BorderFactory.createEmptyBorder(4, 4, 4, 4));
searchPanel.add(searchField, BorderLayout.CENTER);
frame = new JFrame();
frame.setLayout(new BorderLayout(5, 5));
frame.add(searchPanel, BorderLayout.NORTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 500);
center(frame);
frame.setVisible(true);
}
private final void newFilter() {
RowFilter<DefaultTableModel, Object> rf = null;
try {
rf = RowFilter.regexFilter(getFilterText(), 0);
}
catch(PatternSyntaxException e) {
return;
}
rowSorter.setRowFilter(rf);
}
private final String getFilterText() {
String orig = searchField.getText();
return "("+orig.toLowerCase()+")|("+orig.toUpperCase()+")";
}
private void showPopup(DocumentEvent e) {
if(e.getDocument().getLength() > 0) {
if(!popup.isVisible()) {
Rectangle r = searchField.getBounds();
popup.show(searchField, (r.x-4), (r.y+16));
popup.setVisible(true);
}
newFilter();
searchField.grabFocus();
}
else {
popup.setVisible(false);
}
}
private void cycleTableSelectionUp() {
ListSelectionModel selModel = searchTable.getSelectionModel();
int index0 = selModel.getMinSelectionIndex();
if(index0 > 0) {
selModel.setSelectionInterval(index0-1, index0-1);
}
}
private void cycleTableSelectionDown() {
ListSelectionModel selModel = searchTable.getSelectionModel();
int index0 = selModel.getMinSelectionIndex();
if(index0 == -1) {
selModel.setSelectionInterval(0, 0);
}
else if(index0 > -1) {
selModel.setSelectionInterval(index0+1, index0+1);
}
}
private void initTableModel() {
String[] columns = new String[] {"A"};
String[][] data = new String[][]
{
new String[] {"a"},
new String[] {"aa"},
new String[] {"aaab"},
new String[] {"aaabb"},
new String[] {"aaabbbz"},
new String[] {"b"},
new String[] {"bb"},
new String[] {"bbb"},
new String[] {"bbbbbbb"},
new String[] {"bbbbbbbeee"},
new String[] {"bbbbbbbeeexxx"},
new String[] {"ccc"},
new String[] {"cccc"},
new String[] {"ccccc"},
new String[] {"cccccaaaa"},
new String[] {"ccccccaaaa"},
};
searchTableModel.setDataVector(data, columns);
}
private void center(Window w) {
int screenWidth = Toolkit.getDefaultToolkit().getScreenSize().width;
int screenHeight = Toolkit.getDefaultToolkit().getScreenSize().height;
int windowWidth = w.getWidth();
int windowHeight = w.getHeight();
if (windowHeight > screenHeight) {
return;
}
if (windowWidth > screenWidth) {
return;
}
int x = (screenWidth - windowWidth) / 2;
int y = (screenHeight - windowHeight) / 2;
w.setLocation(x, y);
}
public static void main(String ... args) {
new SearchAutoFillTest();
}
}
This component is called autocomplete and is included in a so called swing extensions porject.
Just have a look at: http://swingx.java.net/
There is a webstart with demos: http://swinglabs-demos.java.net/demos/swingxset6/swingxset.jnlp
use AutoComplete JTextField placed into JToolBar / MenuBar, notice you must to sort ArrayList before usage,
use undecoratted JDialog instead of JPopup (still have got a few important bugs),
a) create only one JDialog with parent to the JTextField or JMenuBar or JFrame,
b) always to search for getBounds from AutoComplete JTextField before visible JDialog on the screen, this Bounds are for possitioning JDialog correctly on the screen
c) wrap JDialog#setVisible(true) to the invokeLater()
override Escape for JDialog.setVisible(false)
put there close / hide JButton to avoiding overrive rest of important methods on focusLost (this calendar have got excelent workaround on focusLost, mouseClick, etc ...., could it be very easy to replace calendar funcionality with result from Comparator, you have to download codesource)
you can put there (my view) 6 / 9 / max 12 buttons, you can remove JButton Feels by setBackground(Color.white) for example, you cann't, please don't do it something with JDialog and these JButtons, you job will be only to setText("result from Comparator")
in the case that your ArrayList for AutoComplete JTextField was sorted, then you have two choises
a) easiest override bias from AutoComplete funcionality by add fils separate array for setText() for 6 / 9 / max 12 buttons on popup JDialog, if you setBackground(Color.white), then you don't care somehow about to hide JButtons without text
b) another way could be to create own Comparator for searching (the same AutoComplete funcionality) first 6 / 9 / max 12 matches,
for capturing an events from 6 / 9 / max 12 JButtons use putClientProperty or EventHandler or Swing Actions, where you only to test if text isEmpty :-),
maybe Swing Actions could be the best of ways because its events are scallable and you can enabled/disable (if JButtons text isEmpty) output from this Action by default
It sounds like you want a JComboBox (see Swing guide) rather than a JTextField/JList.
Of course, then you have a drop-down button, but there are possible ways to deal with this - see here.
It would be something along these lines:
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import javax.swing.*;
public class Component extends JComponent {
private final static String[] terms = {"Jesus",
"Jesus walks on water" //...
};
private static ArrayList<String> recent = new ArrayList<String>();
JTextField jtf;
JList jl;
public Component(){
// set up design
jtf = new JTextField();
jtf.setSize(this.getWidth() - 25, 25);
this.add(jtf);
//...
// add key listeners
}
class Listener implements KeyListener{
#Override
public void keyPressed(KeyEvent arg0) {
}
#Override
public void keyReleased(KeyEvent arg0) {
}
#Override
public void keyTyped(KeyEvent arg0) {
if (arg0.getKeyCode() == KeyEvent.VK_DOWN){
// set next item on list
}
else if (arg0.getKeyCode() == KeyEvent.VK_UP){
// set previous item on list
}
else if (arg0.getKeyCode() == KeyEvent.VK_ENTER){
// search
}
else if (arg0.getKeyCode() == KeyEvent.VK_ESCAPE){
jtf.setText("");
}
else{
// check list for matches
}
}
}
}
The default behavior is that all key events go to the component which has the focus. So what you need to do is identify keys which should really go to the other component and install a KeyListener to both.
In that listener, you can forward the events to the other component.
See this answer how to dispatch an event to a new component. In your case, source must be the other component (the list, if your text field originally received the event and vice versa).

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