Develop Reference

Need my GUI to read from a JTextField and show in a JPanel

I have added an action listener to the text field. When the btnReadString (Button Read String) is pressed the program should read what is on the text field and show on the JPanel. but nothing shows on the panel.
stringTextField.addActionListener(new ActionListener() {
public void stringTextField (java.awt.event.ActionEvent e) {
if(e.getSource()==btnReadString) //when the button is pressed
{
String stringParameter = stringTextField.getText(); //gets the text and puts it on this string called "stringParameter"
textPane.setText(stringParameter);//the JPanel is set to what is on the string.
}
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
});

The functionality for the ActionListener should go in the actionPerformed method, as nothings calling the stringTextField method...
stringTextField.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource()==btnReadString) //when the button is pressed
{
String stringParameter = stringTextField.getText(); //gets the text and puts it on this string called "stringParameter"
textPane.setText(stringParameter);//the JPanel is set to what is on the string.
}
}
});
But, based on the code, the ActionListener should be attached to the btnReadString and not the field, as the above logic will never result in anything been executed (as the source of the event will never be btnReadString)
btnReadString.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String stringParameter = stringTextField.getText(); //gets the text and puts it on this string called "stringParameter"
textPane.setText(stringParameter);//the JPanel is set to what is on the string.
}
});
I would suggest having a closer look at How to Write an Action Listener and How to Use Buttons, Check Boxes, and Radio Buttons for more details

You have added the ActionListener to the text field. So the event source is never going to be the button and hence, the code is never going to execute. What you want is to add the ActionListener to the JButton.
Also, the actionPerformed() is there for a reason. All your 'action' code goes inside this method.
So your code should look like this:
btnReadString.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String stringParameter = stringTextField.getText();
textPane.setText(stringParameter);
}
});

Value Change Listener for JavaFX's TextField

I would like to add a kind of listener to my JavaFX's TextField which when ever a user changes the value of the TextField, the Application prints something on the console.
I've searched and i find the following very similar question : Value Change Listener to JTextField
The answer of mentioned question is very clear and efficient, but unfortunately it is only useful for JTextField ( Not JavaFX's TextField) because it says you should use DocumentListener like this:
// Listen for changes in the text
textField.getDocument().addDocumentListener(new DocumentListener() {
public void changedUpdate(DocumentEvent e) {
warn();
}
public void removeUpdate(DocumentEvent e) {
warn();
}
public void insertUpdate(DocumentEvent e) {
warn();
}
but in JavaFX's TextFields you are not able to do it.
So? What is the solution?
(describing with code can be very good but if it is not possible, any hint will be appreciated)

Add a listener to the TextField's textProperty:
TextField textField = new TextField();
textField.textProperty().addListener((observable, oldValue, newValue) -> {
System.out.println("textfield changed from " + oldValue + " to " + newValue);
});

JTable does not accept text from Windows IME keyboard directly [duplicate]

I have a JTable with editable cells. When I click in a cell, it enters edit mode; the same happens when I'm moving through cell using the directional arrows.
Now I want to select the cell instead of start editing, and edit the cell only when the Enter key is pressed.
If any other information is needed, please just ask for it.
Edit: Action for Enter key
class EnterAction extends AbstractAction {
#Override
public void actionPerformed(ActionEvent e) {
JTable tbl = (JTable) e.getSource();
tbl.editCellAt(tbl.getSelectedRow(), tbl.getSelectedColumn());
if (tbl.getEditorComponent() != null) {
tbl.getEditorComponent().requestFocus();
}
}
}
Now this is for left arrow action the rest of 3 are not hard to deduce from this one:
class LeftAction extends AbstractAction {
#Override
public void actionPerformed(ActionEvent e) {
JTable tbl = (JTable)e.getSource();
tbl.requestFocus();
tbl.changeSelection(tbl.getSelectedRow(), tbl.getSelectedColumn() > 0 ? tbl.getSelectedColumn()-1:tbl.getSelectedColumn(), false, false);
if(tbl.getCellEditor()!=null)
tbl.getCellEditor().stopCellEditing();
}
}
And this is how you bind this actions:
final String solve = "Solve";
KeyStroke enter = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0);
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(enter, solve);
table.getActionMap().put(solve, new EnterAction());
final String sel = "Sel";
KeyStroke arrow = KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0);
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(arrow, sel);
table.getActionMap().put(sel, new LeftAction());
Oh,i almost forgot,to select the cell instead of edit on Mouse Click:
public static MouseListener mAdapterTable = new MouseListener()
{
#Override
public void mousePressed(MouseEvent e)
{
JTable tbl=((JTable)e.getComponent());
if(tbl.isEditing())
{
tbl.getCellEditor().stopCellEditing();
}
}
#Override
public void mouseClicked(MouseEvent e) {
JTable tbl=((JTable)e.getComponent());
if(tbl.isEditing() )
tbl.getCellEditor().stopCellEditing();
}
#Override
public void mouseReleased(MouseEvent e) {
JTable tbl=((JTable)e.getComponent());
if(tbl.isEditing() )
tbl.getCellEditor().stopCellEditing();
}
};
The EventListner must be added to table like so:
table.addMouseListener(mAdapterTable);

Use Key Bindings for this. Most Look & Feel implementations already bind F2 to the table's startEditing action, but you add a different binding:
tree.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0), "startEditing");
This will effectively replace the previous binding of Enter to the table's selectNextRowCell action.

Here is what i would do:
First enable the single cell selection for the JTable
Create a KeyAdapter or KeyListener for the JTable or for the JPanel,
what contains your table.
In the KeyAdapter's keyPressed() method enter the edit mode of the
selected cell, something like this:
http://www.exampledepot.com/egs/javax.swing.table/StopEdit.html
You can check in the keyPressed() method, if the user pressed the right button for editing. I'm not sure, if the normal (double click) editing is disabled in your table, then what happens, if you try to edit it programmatically, but if it doesn't work, then you can enable the editing on the selected cell, when the user presses the edit button, then when he/she finished, disable it again.

Clicking the textfield and clear the text?

Is it possible that when I clicked the textfield it would clear the recent text that was inputed there?. Mine was like, suppose these are textfields.
Name: Last Name First Name Middle Initial
Then I would click the Last Name and it would be cleared, same as First Name and Middle Initial. thanks for reading, hope you can help me.

Consider a FocusListener, one where all the text is selected:
myTextField.addFocusListener(new FocusAdapter() {
public void focusGained(FocusEvent fEvt) {
JTextField tField = (JTextField)fEvt.getSource();
tField.selectAll();
}
});
By selecting all of the text, you give the user the option of either typing and thus deleting the current text and replacing it with the new text, or using the mouse or arrow keys to keep the current text and possibly change it.

I think Hovercraft is right. Better to use a FocusListener for this purpose.
I would write a utility class that could deal with this, I've done something similar for auto select. Means I don't have to extend every text component that comes along or mess around with lost of small focus listeners that do the same thing.
public class AutoClearOnFocusManager extends FocusAdapter {
private static final AutoClearOnFocusManager SHARED_INSTANCE = new AutoClearOnFocusManager();
private AutoClearOnFocusManager() {
}
public static AutoClearOnFocusManager getInstance() {
return SHARED_INSTANCE;
}
#Override
public void focusGained(FocusEvent e) {
Component component = e.getComponent();
if (component instanceof JTextComponent) {
((JTextComponent)component).setText(null);
}
}
public static void install(JTextComponent comp) {
comp.addFocusListener(getInstance());
}
public static void uninstall(JTextComponent comp) {
comp.removeFocusListener(getInstance());
}
}
Then you just need to use
JTextField textField = new JTextField("Some text");
AutoClearOnFocusManager.install(textField);
If you're just looking to supply a "prompt" (text inside the field that prompts the user), you could also look at the Prompt API

Why don't use the mouseClicked event?
So, you can have something like
jTextFieldMyText.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jTextFieldMyTextMouseClicked(evt);
}
});
private void jTextFieldMyTextMouseClicked(java.awt.event.MouseEvent evt) {
jTextFieldMyText.setText("");
}
In the case of focus
jTextFieldMyText.addFocusListener(new java.awt.event.FocusAdapter() {
public void focusGained(java.awt.event.FocusEvent evt) {
jTextFieldMyTextFocusGained(evt);
}
});
private void jTextFieldMyTextFocusGained(java.awt.event.MouseEvent evt) {
jTextFieldMyText.setText("");
}
If deleting text inmediatelly isn't what's wanted, use selectAll() instead of setText("") as suggested many times

Changing the Background of a button after it is clicked (i.e. after Action performed)

I am trying to change the background of a JButton after it is clicked. Currently my buttons are located in a GridLayout (3x3) and look like this:
tiles.add(new JButton(new AbstractAction("") {
#Override
public void actionPerformed(ActionEvent e) {
this.setIcon("foo.png");
}
}));
This does not work. How do I manipulate the background of the image from within the actionperformed?

A JToggleButton might be ideal for this, as shown on Swing JToolbarButton pressing
Note that you would need to add some code to ensure a button was only clickable once.
Alternately you might use a standard JButton and call AbstractButton.setDisabledIcon(Icon). Disable the button when clicked, and it will flip to the alternate icon.

You can create your own listener that implements the MouseListener. This way, you can control when the background of the button changes (when the mouse is released, pressed, etc). Here is an example
//Add the listener to the button
myButton.addMouseListener(new customActionListener());
//Create the listener
class customActionListener implements MouseListener {
public void mouseExited(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
Icon icon = new ImageIcon("icon.gif");
myButton.setIcon(icon);
}
public void mouseClicked(MouseEvent e) {
}
}
At whatever point you want to set the background back to its default, use:
myButton.setIcon(new ImageIcon());