I want to update my text area along with typing in the text field but i get a delay of 1 keystroke while typing i.e when i press a key the previous key is displayed.Here is my snippet
private void jTextField1KeyTyped(java.awt.event.KeyEvent evt)
{
String a = jTextField1.getText();
jTextArea1.setText(a);
}
I would not recommend using KeyListeners
Simply add a DocumentListener to your JTextField via:
textField.getDocument().addDocumentListener(new DocumentListener() {
#Override
public void insertUpdate(DocumentEvent de) {
}
#Override
public void removeUpdate(DocumentEvent de) {
}
#Override
public void changedUpdate(DocumentEvent de) {
}
});
Inside each of the methods ( insertUpdate,removeUpdate and changedUpdate) simply put in a call to set the text of your JTextArea via setText():
textArea.setText(textField.getText());
Here is an example I made:
import java.awt.BorderLayout;
import javax.swing.*;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
public class Test {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Test().createAndShowUI();
}
});
}
private void createAndShowUI() {
final JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
initComponents(frame);
frame.setResizable(false);
frame.pack();
frame.setVisible(true);
}
private void initComponents(JFrame frame) {
final JTextField jtf = new JTextField(20);
final JTextArea ta = new JTextArea(20,20);
ta.setEditable(false);
jtf.getDocument().addDocumentListener(new DocumentListener() {
#Override
public void insertUpdate(DocumentEvent de) {
ta.setText(jtf.getText());
}
#Override
public void removeUpdate(DocumentEvent de) {
ta.setText(jtf.getText());
}
#Override
public void changedUpdate(DocumentEvent de) {
//Plain text components don't fire these events.
}
});
frame.getContentPane().add(jtf, BorderLayout.WEST);
frame.getContentPane().add(ta, BorderLayout.EAST);
}
}
You should do that under the keyReleased event instead of the keyTyped and it will work as you need.
You need to wait till the event on your TextField is processed before updating the TextArea. Your code update the TextArea before the TextField is done processing the new typed character. Hence the text set in the TextArea is one keystroke behind.
You could try using recursion by referencing the method inside the method (avoid loops though).
Related
I have some problems with using dispose() method in my GUI project.
I' am making a GUI swing application for some kind of Elections in IntelliJ.
My problem is, by clicking a button(Confirm1, or 2 or 3) I want to open new JFrame which is checking the age of voter and closes the current JFrame where this button is located by calling dispose().
But frame.dispose(); doesn't work.
I have my JFrame declared in public static main().
Should I make reference for it in my ActionListener? I have been looking for solution, but I couldn't find any.
Here is a code:
import javax.swing.*; //another libraries
public class ElectionGUI {
private JPanel labelElection; // another texfields or etc.
private JButton Confirm1;
private JButton Confirm3;
private JButton Confirm2;
private JPanel Elections;
public VotesGUI(){
Votes votes = new Votes("...","...",0);
listX.addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
if(!e.getValueIsAdjusting()){
NrX.setText(listX.getSelectedValue().toString());
}
}
});
listY.addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
if(!e.getValueIsAdjusting()){
NrY.setText(listY.getSelectedValue().toString());
}
}
});
listZ.addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
if(!e.getValueIsAdjusting()){
NrZ.setText(listZ.getSelectedValue().toString());
}
}
});
Confirm1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
votes.VotesX();
votes.countVotes();
CheckAge age = new CheckAge();
age.Check(); /// referention, to my next //Jframe called psvm Check();
}
});
Confirm2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
votes.VotesY();
votes.countVotes();
CheckAge age = new CheckAge();
age.Check();
}
});
Confirm3.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
votes.VotesZ();
votes.countVotes();
CheckAge age = new CheckAge();
age.Check();
}
});
}
public static void main(String[] args) {
JFrame frame = new JFrame("Elentions");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setContentPane(new ElectionGUI().labelElection);
frame.pack();
}
}
I want to initialize a Graphical User Interface (GUI) for the user to input a form. After this is accomplished i want to open a new GUI, but as soon as the first GUI pops-up the next one is initialized to.
Is there any way to solve this without using waits and notifies?
here is an example of my code:
public static void main(String[] args) {
new GUIForm();
// wait until the user inputs the complete form
new GUIWelcome();
}
It is really simple I woild like to keep it that way.
Create an Interface OnActionListener
public interface OnActionListener {
public void onAction();
}
Add these code in GUIForm class
private OnActionListener listener;
private JButton action;
public GUIForm(OnActionListener listener) {
this.listener = listener;
action = new JButton("Action");
action.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
GUIForm.this.listener.onAction();
}
});
}
Now you can achieve that
new GUIForm(new OnActionListener() {
#Override
public void onAction() {
new GUIWelcome();
}
});
You need to use some sort pub/sub mechanism. This in a nutshell is what you need:
public class PubSub {
public static void main(String[] args) {
JFrame frame1 = new JFrame("GUIForm");
frame1.setSize(640, 480);
JButton button = new JButton("User Input");
JFrame frame2 = new JFrame("Welcome");
frame2.setSize(320, 240);
button.addMouseListener(new MouseAdapter() {
#Override
public void mouseEntered(MouseEvent e) {
button.setCursor(new Cursor(Cursor.HAND_CURSOR));
}
#Override
public void mouseExited(MouseEvent e) {
button.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
#Override
public void mouseClicked(MouseEvent e) {
frame2.setVisible(true);
}
});
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.add(button);
frame1.setVisible(true);
}
}
This version uses JFrame's listeners, but you could implement your on callback mechanism to accomplish the same
I have a login form where a user can enter his credentials to login. I have a JLabel that serves to display the text telling the user that the user name cannot be empty. This label is display after a user click the login button when the text field is empty.
I want that the moment the user starts typing in the text field the label with the information should disappear.How do I achieve this behavior?
Here is the code:
public class JTextFiledDemo {
private JFrame frame;
JTextFiledDemo() {
frame = new JFrame();
frame.setVisible(true);
frame.setSize(300, 300);
frame.setLayout(new GridLayout(4, 1));
frame.setLocationRelativeTo(null);
iniGui();
}
private void iniGui() {
JLabel error = new JLabel(
"<html><font color='red'> Username cannot be empty!<></html>");
error.setVisible(false);
JButton login = new JButton("login");
JTextField userName = new JTextField(10);
frame.add(userName);
frame.add(error);
frame.add(login);
frame.pack();
login.addActionListener((ActionEvent) -> {
if (userName.getText().equals("")) {
error.setVisible(true);
}
});
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JTextFiledDemo tf = new JTextFiledDemo();
}
});
}
}
You have to create DocumentListener:
DocumentListener dl = new DocumentListener()
{
#Override
public void insertUpdate(DocumentEvent de)
{
error.setVisible(false);
}
#Override
public void removeUpdate(DocumentEvent de)
{
//
}
#Override
public void changedUpdate(DocumentEvent de)
{
error.setVisible(false);
}
};
then for your text fields:
login.getDocument().addDocumentListener(dl);
For that purposes you need to use DocumentListener on your JTextField, here is tutorial.
As example:
userName.getDocument().addDocumentListener(new DocumentListener() {
#Override
public void insertUpdate(DocumentEvent de){
event(de);
}
#Override
public void removeUpdate(DocumentEvent de) {
event(de);
}
#Override
public void changedUpdate(DocumentEvent de){
event(de);
}
private void event(DocumentEvent de){
error.setVisible(de.getDocument().getLength() == 0);
// as mentioned by nIcE cOw better to use Document from parameter
frame.revalidate();
frame.repaint();
}
});
error must be final(for java lower than 8 version).
Also at start your field is empty, so may be need to use setVisible(true) on error label.
You can add a keyListener in the input filed
userName.addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent arg0) {
}
#Override
public void keyReleased(KeyEvent arg0) {
}
#Override
public void keyPressed(KeyEvent arg0) {
error.setVisible(false);
}
});
I'm studying AWT and swing, and I'm beginning with some simple GUIs to get the hang of it.I wrote the following code,which works fine until I try to close the application and it won't exit.
import java.awt.*;
import java.awt.event.*;
public class AWTCounter extends Frame{
private Button button;
private Label label;
private TextField txt;
private int count=0;
public AWTCounter(){
super("AWT Counter");
addWindowListener(new WindowListener(){
#Override
public void windowActivated(WindowEvent arg0) {}
#Override
public void windowClosed(WindowEvent arg0) {
System.out.println("closing time!");
System.exit(0);
}
#Override
public void windowClosing(WindowEvent arg0) {}
#Override
public void windowDeactivated(WindowEvent arg0) {}
#Override
public void windowDeiconified(WindowEvent arg0) {}
#Override
public void windowIconified(WindowEvent arg0) {}
#Override
public void windowOpened(WindowEvent arg0) {}
});
label = new Label();
add(label);
label.setText("Counter");
txt = new TextField();
txt.setEditable(false);
add(txt);
button = new Button("count");
add(button);
setSize(400,100);
setLayout(new FlowLayout());
setVisible(true);
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent arg0) {
++count;
txt.setText(Integer.toString(count));
}
});
}
public static void main(String [] args){
Thread t =new Thread(new Runnable(){
public void run(){
new AWTCounter();
}
});
t.start();
}
}
I "registered" the WindowListener in the source component (the AWTCounter in this case, which is a Frame) and implemented the only method I was going to use, but it never respond... any idea as to why it behaves like that?
thanks a lot guys!
See the API for Frame - for the WINDOW_CLOSING event: "If the program doesn't explicitly hide or dispose the window while processing this event, the window close operation is canceled." - if you move your logic into the windowClosing method the application should exit. A Swing JFrame is a bit more friendly (you can set the default closing behavior to exit on close if you wish to exit the application upon closing the JFrame without the need for the WindowListener).
Last but not least, I'd recommend creating your GUI on the EventDispatchThread. For instance:
public static void main(String [] args) throws Exception{
Runnable t = new Runnable(){
public void run(){
new AWTCounter();
}
};
SwingUtilities.invokeAndWait(t);
}
Try doing this:
#Override
public void windowClosing(WindowEvent event) {
System.exit(0);
}
I wanted to develop a console-like interface, similar to IDLE. That involved determining how to prevent a certain part of the text in a JTextField from being edited. For example:
>>> help
Where the ">>> " is uneditable. The caret must never move behind a certain position, and the text behind that position cannot be edited in any way.
I looked at NavigationFilter, but it doesn't seem to prevent keyboard driven manipulation of the caret.
This shows how to do it with a NavigationFilter:
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class NavigationFilterPrefixWithBackspace extends NavigationFilter
{
private int prefixLength;
private Action deletePrevious;
public NavigationFilterPrefixWithBackspace(int prefixLength, JTextComponent component)
{
this.prefixLength = prefixLength;
deletePrevious = component.getActionMap().get("delete-previous");
component.getActionMap().put("delete-previous", new BackspaceAction());
component.setCaretPosition(prefixLength);
}
#Override
public void setDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias)
{
fb.setDot(Math.max(dot, prefixLength), bias);
}
#Override
public void moveDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias)
{
fb.moveDot(Math.max(dot, prefixLength), bias);
}
class BackspaceAction extends AbstractAction
{
#Override
public void actionPerformed(ActionEvent e)
{
JTextComponent component = (JTextComponent)e.getSource();
if (component.getCaretPosition() > prefixLength)
{
deletePrevious.actionPerformed( null );
}
}
}
private static void createAndShowUI()
{
JTextField textField = new JTextField("Prefix_", 20);
textField.setNavigationFilter( new NavigationFilterPrefixWithBackspace(7, textField) );
JFrame frame = new JFrame("Navigation Filter Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(textField);
frame.pack();
frame.setLocationRelativeTo( null );
frame.setVisible(true);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
createAndShowUI();
}
});
}
}
Spent a little while figuring this out, so I thought I would share my solution for anyone else with the same dilemma. I don't know if it's optimal, but it does seem to work.
It prevents the user from using backspace behind the postion n. It also moves the caret back to n for any other events, such as (illegally) changing the caret position with the arrow keys or mouse. Finally, it resets the text and caret position after a entry is processed.
EDIT: While I'm leaving this answer here for posterity, see the accepted answer for the best way to solve this problem.
JTextField in = new JTextField();
final String protectMe = ">>> "; //protect this text
final int n = protectMe.length();
in.setText(protectMe);
in.setCaretPosition(n);
in.addCaretListener(new CaretListener()
{
#Override
public void caretUpdate(CaretEvent e)
{
if (e.getDot() < n)
{
if (!(in.getText().length() < n))
in.getCaret().setDot(n);
}
}
});
in.addKeyListener(new KeyListener()
{
#Override
public void keyPressed(KeyEvent arg0)
{
if (in.getCaret().getDot() <= n)
{
in.setText(protectMe + in.getText().substring(n));
arg0.consume();
}
}
#Override
public void keyReleased(KeyEvent arg0){}
#Override
public void keyTyped(KeyEvent arg0){}
});
in.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
String input = in.getText().substring(n).trim();
//do something
in.setText(protectMe);
in.setCaretPosition(n);
}
});
As usual, let me know if there's anything I missed!