Develop Reference

Convert JSpinner value to a new int

I am using WindowBuilder to create a GUI.
I'm kinda new to JFrame and I have a problem: I added a JSpinner and I want to save the number that I put in my spinner to an int so I can use it later on. Can someone please help me? Thanks.
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JTextField;
import java.awt.BorderLayout;
import javax.swing.SwingConstants;
import java.awt.Font;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import java.awt.Color;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class frame1 {
private JFrame frame;
private JTextField txtHoeveelEuroWil;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
frame1 window = new frame1();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public frame1() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JSpinner spinner = new JSpinner();
spinner.setModel(new SpinnerNumberModel(20, 20, 500, 20));
spinner.setBounds(116, 100, 200, 50);
frame.getContentPane().add(spinner);
int value;
JButton btnNewButton = new JButton("OK");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
//value=Integer.parseint ???
//what should I type here to save the number that I entered
//in the spinner?
}
});
btnNewButton.setBounds(172, 177, 89, 32);
frame.getContentPane().add(btnNewButton);
}
}

Try this
try {
spinner.commitEdit();
}
catch (ParseException pe) {{
// Edited value is invalid, spinner.getValue() will return
// the last valid value, you could revert the spinner to show that:
JComponent editor = spinner.getEditor()
if (editor instanceof DefaultEditor) {
((DefaultEditor)editor).getTextField().setValue(spinner.getValue());
}
// reset the value to some known value:
spinner.setValue(fallbackValue);
// or treat the last valid value as the current, in which
// case you don't need to do anything.
}
int value = (Integer)spinner.getValue();

To save the value and use it, you can set a field variable to hold it. So in your fram1 class, add a getter and setter for the variable. Then set the variable on button click.
public class frame1 {
//default to -1
private int spinnerValue = -1;
private void setSpinnerValue(aValue) {
spinnerValue = aValue;
}
public int getSpinnerValue() {
return spinnerValue;
}
private void initialize() {
// blah blah
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// here set a value
setSpinnerValue((Integer) spinner.getValue());
}
});
}
}
then when you need the value, you can use the instance of frame1 and call this method
frame1.getSpinnerValue();

Needing to return value from user input

a basic problem that i can't figure out, tried a lot of things and can't get it to work, i need to be able to get the value/text of the variable
String input;
so that i can use it again in a different class in order to do an if statement based upon the result
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
public class pInterface extends JFrame {
String input;
private JTextField item1;
public pInterface() {
super("PAnnalyser");
setLayout(new FlowLayout());
item1 = new JTextField("enter text here", 10);
add(item1);
myhandler handler = new myhandler();
item1.addActionListener(handler);
System.out.println();
}
public class myhandler implements ActionListener {
// class that is going to handle the events
public void actionPerformed(ActionEvent event) {
// set the variable equal to empty
if (event.getSource() == item1)// find value in box number 1
input = String.format("%s", event.getActionCommand());
}
public String userValue(String input) {
return input;
}
}
}

You could display the window as a modal JDialog, not a JFrame and place the obtained String into a private field that can be accessed via a getter method. Then the calling code can easily obtain the String and use it. Note that there's no need for a separate String field, which you've called "input", since we can easily and simply extract a String directly from the JTextField (in our "getter" method).
For example:
import java.awt.Dialog.ModalityType;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import javax.swing.*;
import javax.swing.text.JTextComponent;
public class TestPInterface {
#SuppressWarnings("serial")
private static void createAndShowGui() {
final JFrame frame = new JFrame("TestPInterface");
// JDialog to hold our JPanel
final JDialog pInterestDialog = new JDialog(frame, "PInterest",
ModalityType.APPLICATION_MODAL);
final MyPInterface myPInterface = new MyPInterface();
// add JPanel to dialog
pInterestDialog.add(myPInterface);
pInterestDialog.pack();
pInterestDialog.setLocationByPlatform(true);
final JTextField textField = new JTextField(10);
textField.setEditable(false);
textField.setFocusable(false);
JPanel mainPanel = new JPanel();
mainPanel.add(textField);
mainPanel.add(new JButton(new AbstractAction("Get Input") {
#Override
public void actionPerformed(ActionEvent e) {
// show dialog
pInterestDialog.setVisible(true);
// dialog has returned, and so now extract Text
textField.setText(myPInterface.getText());
}
}));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
// by making the class a JPanel, you can put it anywhere you want
// in a JFrame, a JDialog, a JOptionPane, another JPanel
#SuppressWarnings("serial")
class MyPInterface extends JPanel {
// no need for a String field since we can
// get our Strings directly from the JTextField
private JTextField textField = new JTextField(10);
public MyPInterface() {
textField.addFocusListener(new FocusAdapter() {
#Override
public void focusGained(FocusEvent e) {
JTextComponent textComp = (JTextComponent) e.getSource();
textComp.selectAll();
}
});
add(new JLabel("Enter Text Here:"));
add(textField);
textField.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Window win = (Window) SwingUtilities.getWindowAncestor(MyPInterface.this);
win.dispose();
}
});
}
public String getText() {
return textField.getText();
}
}

A Good way of doing this is use Callback mechanism.
I have already posted an answer in the same context.
Please find it here JFrame in separate class, what about the ActionListener?.

Your method is a bit confusing:
public String userValue(String input) {
return input;
}
I guess you want to do something like this:
public String getInput() {
return input;
}
public void setInput(String input) {
this.input = input;
}
Also your JFrame is not visible yet. Set the visibility like this setVisible(true)

Clear JTextField Contents on Click

So I've built a very basic Web browser - I'm trying desperately to remove the contents of the address bar when a user clicks on it (JTextField) this appears with some text in as default. Any advice is appreciated.
Have a great day!
MY CODE
import java.awt.*;
import java.awt.event.*;
import java.io.IOException;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
public class Web_Browser extends JFrame {
private final JTextField addressBar;
private final JEditorPane display;
// Constructor
public Web_Browser() {
super("Web Browser");
addressBar = new JTextField("Click & Type Web Address e.g. http://www.google.com");
addressBar.addActionListener(
new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
loadGo(event.getActionCommand());
}
}
);
add(addressBar, BorderLayout.NORTH);
display = new JEditorPane();
display.setEditable(false);
display.addHyperlinkListener(
new HyperlinkListener(){
#Override
public void hyperlinkUpdate(HyperlinkEvent event){
if(event.getEventType()==HyperlinkEvent.EventType.ACTIVATED){
loadGo(event.getURL().toString());
}
}
}
);
add(new JScrollPane(display), BorderLayout.CENTER);
setSize(500,300);
setVisible(true);
}
// loadGo to sisplay on the screen
private void loadGo(String userText) {
try{
display.setPage(userText);
addressBar.setText(userText);
}catch(IOException e){
System.out.println("Invalid URL, try again");
}
}
}

Use a FocusListener. On focusGained, select all.
addressBar.addFocusListener(new FocusAdapter() {
#Override
public void focusGained(FocusEvent e) {
JTextComponent textComponent = (JTextComponent) e.getSource();
textComponent.selectAll();
}
});
For example:
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import javax.swing.*;
import javax.swing.text.JTextComponent;
#SuppressWarnings("serial")
public class FocusExample extends JPanel {
private static final int TF_COUNT = 5;
private JTextField[] textFields = new JTextField[TF_COUNT];
public FocusExample() {
for (int i = 0; i < textFields.length; i++) {
textFields[i] = new JTextField("Foo " + (i + 1), 10);
textFields[i].addFocusListener(new FocusAdapter() {
#Override
public void focusGained(FocusEvent e) {
JTextComponent textComponent = (JTextComponent) e.getSource();
textComponent.selectAll();
}
});
add(textFields[i]);
}
}
private static void createAndShowGui() {
FocusExample mainPanel = new FocusExample();
JFrame frame = new JFrame("FocusExample");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
This gives the user the option of leaving the previous text in place, of adding to the previous text, or of simply over-writing it by typing.

new JTextField("Click & Type Web Address e.g. http://www.google.com");
Maybe you want the Text Prompt, which doesn't actually store any text in the text field. It just gives the user a hint what the text field is for.
This is beneficial so that you don't generate DocumentEvents etc., since you are not actually changing the Document.

Add a mouseListener instead of your actionListener method.
addressBar.addMouseListener(new MouseAdapter(){
#Override
public void mouseClicked(MouseEvent e){
addressBar.setText("");
}

jTextArea stops showing highlighting on text after losing focus

When my jTextArea is in focus it allows text highlighting, but it doesn't show the text selection when it loses focus. Is it possible to continue displaying the text highlighting even if the user moves focus to another component on the related jFrame?

One simple workaround for caret selection is a simple subclassing of DefaultCaret:
textArea.setCaret(new DefaultCaret() {
#Override
public void setSelectionVisible(boolean visible) {
super.setSelectionVisible(true);
}
});

but doesn't show selection on text when looses focus.
there are three ways:
use JTextPane, see Oracle tutorial
easiest in the case that we talking about selection as painting artefact from Mouse Event see my question How to override DefaultCaret#setBlinkRate(), great knowledge and answer by #camickr
or programatically override Highlighter
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.Highlighter;
import javax.swing.text.JTextComponent;
public class MultiHighlight implements ActionListener {
private JTextComponent comp;
private String charsToHighlight;
public MultiHighlight(JTextComponent c, String chars) {
comp = c;
charsToHighlight = chars;
}
#Override
public void actionPerformed(ActionEvent e) {
Highlighter h = comp.getHighlighter();
h.removeAllHighlights();
String text = comp.getText().toUpperCase();
for (int j = 0; j < text.length(); j += 1) {
char ch = text.charAt(j);
if (charsToHighlight.indexOf(ch) >= 0) {
try {
h.addHighlight(j, j + 1, DefaultHighlighter.DefaultPainter);
} catch (BadLocationException ble) {
}
}
}
}
public static void main(String args[]) {
final JFrame frame = new JFrame("MultiHighlight");
frame.add(new JTextField("Another focusable JComponents"), BorderLayout.NORTH);
JTextArea area = new JTextArea(10, 20);
area.setText("This is the story\nof the hare who\nlost his spectacles."
+ "\nThis is the story\nof the hare who\nlost his spectacles.");
frame.getContentPane().add(new JScrollPane(area), BorderLayout.CENTER);
JButton b = new JButton("Highlight All Vowels");
b.addActionListener(new MultiHighlight(area, "aeiouAEIOU"));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(b, BorderLayout.SOUTH);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
frame.pack();
frame.setVisible(true);
}
});
}
}

JFormattedTextfield only validate when pressed enter

For a task I need to make a JFormattedTextField with the following behavior:
If value is edited and isn't equal to the last validated value the background must become yellow.
Value validation may take place at any time
If focus is lost nothing should happen (if background is yellow it should remain yellow,...)
Action should be taken when Enter is pressed
I can't seem to find the correct combination of Listeners to accomplish this. I tried using KeyAdapter, InputVerifier and PropertyChangeListenerbut that gives me very ugly code wich only works for 80%.
How should this be done?
Edit: I wrote a small example:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.text.ParseException;
import javax.swing.AbstractAction;
import javax.swing.InputVerifier;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Test extends JPanel {
private JFormattedTextField field;
private JLabel label;
private JButton btn;
public Test() {
super(new BorderLayout());
label = new JLabel("Enter a float value:");
btn = new JButton(new AbstractAction("Print to stdout"){
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(field.getValue());
}
});
field = new JFormattedTextField(new Float(9.81));
field.addKeyListener(new KeyAdapter(){
#Override
public void keyPressed(KeyEvent e){
field.setBackground(Color.YELLOW);
}
#Override
public void keyTyped(KeyEvent e){
if(e.getKeyCode() == KeyEvent.VK_ENTER){
try{
field.commitEdit();
field.setBackground(Color.WHITE);
}catch(ParseException e1){
field.setBackground(Color.RED);
}
}
}
});
field.setInputVerifier(new InputVerifier(){
#Override
public boolean verify(JComponent comp) {
try{
field.commitEdit();
field.setBackground(Color.YELLOW);
return true;
}catch(ParseException e){
field.setBackground(Color.RED);
return false;
}
}
});
add(label, BorderLayout.NORTH);
add(field, BorderLayout.CENTER);
add(btn, BorderLayout.SOUTH);
}
public static void main(String[] args) {
JFrame window = new JFrame("InputVerifier test program");
Container cp = window.getContentPane();
cp.add(new Test());
window.pack();
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setVisible(true);
}
}
This almost does everything I want. But the problem is the ENTER key is never caught. I think it is consumed before it reaches my KeyListener, but how can I prevent this?
Even if this can be prevented, I still have the feeling there should be a cleaner why to accomplish what above code does.

Try your hands on this code sample, tell me is this the desired behaviour, or you expecting something else, other than this :
import java.awt.*;
import java.awt.event.*;
import java.text.NumberFormat;
import javax.swing.*;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
public class JFormattedExample
{
private String lastValidValue;
private void createAndDisplayGUI()
{
JFrame frame = new JFrame("JFormattedTextField Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
final JFormattedTextField ftf = new JFormattedTextField(
NumberFormat.getNumberInstance());
ftf.setColumns(10);
ftf.setFocusLostBehavior(JFormattedTextField.PERSIST);
ftf.setValue(100);
lastValidValue = "100";
ftf.addCaretListener(new CaretListener()
{
public void caretUpdate(CaretEvent ce)
{
System.out.println("Last Valid Value : " + lastValidValue);
if (ftf.isEditValid())
{
String latestValue = ftf.getText();
System.out.println("Latest Value : " + latestValue);
if (!(latestValue.equals(lastValidValue)))
ftf.setBackground(Color.YELLOW.darker());
else
{
lastValidValue = ftf.getText();
ftf.setBackground(Color.WHITE);
}
}
else
{
System.out.println("Invalid Edit Entered.");
}
}
});
contentPane.add(ftf);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new JFormattedExample().createAndDisplayGUI();
}
});
}
}