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Update a custom JLabel in all frames

I have a instance of a custom JLabel and i want to changes its text in all frames, but the text is changing only on the last opened frame. There's a way i can achieve this?
Here's what happens:
And my code:
App.java
package test;
import javax.swing.JFrame;
public class App extends JFrame {
protected static App app;
private String loggedUser;
private MyCustomLabel myCustomLabel;
public App() {
loggedUser = "User One";
myCustomLabel = new MyCustomLabel(loggedUser);
}
public static App getApp() {
return app;
}
public MyCustomLabel getMyCustomLabel() {
return myCustomLabel;
}
public String getLoggedUser() {
return loggedUser;
}
public void setLoggedUser(String loggedUser) {
this.loggedUser = loggedUser;
}
}
FrmApp.java
package test;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
/**
*
* #author Marco
*/
public class FrmApp extends App {
public FrmApp() {
app = new App();
initComponents();
}
private void initComponents() {
setLayout(new FlowLayout());
setSize(300, 200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
btnFrmOne = new JButton("Open frmOne");
btnFrmOne.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
FrmOne frmOne = new FrmOne();
frmOne.setVisible(true);
}
});
add(btnFrmOne);
btnFrmTwo = new JButton("Open frmTwo");
btnFrmTwo.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
FrmTwo frmTwo = new FrmTwo();
frmTwo.setVisible(true);
}
});
add(btnFrmTwo);
btnChangeUser = new JButton("Change user");
btnChangeUser.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (App.getApp().getLoggedUser().equals("User One")) {
App.getApp().setLoggedUser("User Two");
} else {
App.getApp().setLoggedUser("User One");
}
App.getApp().getMyCustomLabel().refresh();
}
});
add(btnChangeUser);
}
private JButton btnFrmOne;
private JButton btnFrmTwo;
private JButton btnChangeUser;
public static void main(String args[]) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
Logger.getLogger(FrmApp.class.getName()).log(Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
Logger.getLogger(FrmApp.class.getName()).log(Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
Logger.getLogger(FrmApp.class.getName()).log(Level.SEVERE, null, ex);
} catch (UnsupportedLookAndFeelException ex) {
Logger.getLogger(FrmApp.class.getName()).log(Level.SEVERE, null, ex);
}
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new FrmApp().setVisible(true);
}
});
}
}
FrmOne.java
package test;
import java.awt.FlowLayout;
import javax.swing.JFrame;
public class FrmOne extends JFrame {
public FrmOne() {
initComponents();
}
private void initComponents() {
setLayout(new FlowLayout());
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setSize(150, 100);
add(App.getApp().getMyCustomLabel());
}
}
FrmTwo.java
package test;
import java.awt.FlowLayout;
import javax.swing.JFrame;
public class FrmTwo extends JFrame {
public FrmTwo() {
initComponents();
}
private void initComponents() {
setLayout(new FlowLayout());
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setSize(150, 100);
add(App.getApp().getMyCustomLabel());
}
}
MyCustomLabel.java
package test;
import javax.swing.JLabel;
public class MyCustomLabel extends JLabel {
public MyCustomLabel(String loggedUser) {
initComponents(loggedUser);
}
private void initComponents(String loggedUser) {
setText(loggedUser);
}
public void refresh() {
setText(App.getApp().getLoggedUser());
}
}
Update
This is what im doing now to do what i wanted.
App.java
public class App extends JFrame {
public App() {
User user = new User(1, "User One");
LoggedUser.getInstance().setUser(user);
initComponents();
}
public static void main(String[] args) {
new App().setVisible(true);
}
private void initComponents() {
setSize(200, 200);
setLocation(400, 200);
setLayout(new FlowLayout());
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JButton btn1 = new JButton("dlgOne");
btn1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
DlgOne dlgOne = new DlgOne(App.this, false);
dlgOne.setVisible(true);
}
});
JButton btn2 = new JButton("dlgTwo");
btn2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
DlgTwo dlgTwo = new DlgTwo(App.this, false);
dlgTwo.setVisible(true);
}
});
JButton btn3 = new JButton("change user");
btn3.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (LoggedUser.getInstance().getUser().getId() == 1) {
User user = new User(2, "User Two");
LoggedUser.getInstance().setUser(user);
} else {
User user = new User(1, "User One");
LoggedUser.getInstance().setUser(user);
}
}
});
add(btn1);
add(btn2);
add(btn3);
}
}
MyCustomPanel.java
public class MyCustomPanel extends JPanel implements Observer {
private JLabel label;
public MyCustomPanel() {
initComponents();
}
#Override
public void update(Observable o, Object arg) {
//LoggedUser u = (LoggedUser) o;
//System.out.println(u.getUser().getId());
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
label.setText(LoggedUser.getInstance().getUser().getName());
}
});
}
private void initComponents() {
LoggedUser.getInstance().addObserver(this);
label = new JLabel(LoggedUser.getInstance().getUser().getName());
add(label);
}
}
User.java
public class User {
private int id;
private String name;
public User(int id, String name) {
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
DlgOne.java
public class DlgOne extends JDialog {
public DlgOne(Frame owner, boolean modal) {
super(owner, modal);
initComponents();
}
private void initComponents() {
setTitle("dlgOne");
setSize(200, 200);
setLocation(600, 200);
setLayout(new FlowLayout());
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
add(new MyCustomPanel());
}
}
DlgTwo.java
public class DlgTwo extends JDialog {
public DlgTwo(Frame owner, boolean modal) {
super(owner, modal);
initComponents();
}
private void initComponents() {
setTitle("dlgTwo");
setSize(200, 200);
setLocation(800, 200);
setLayout(new FlowLayout());
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
add(new MyCustomPanel());
}
}
LoggedUser.java
public class LoggedUser extends Observable {
private static LoggedUser instance;
public static LoggedUser getInstance() {
if (instance == null) {
instance = new LoggedUser();
}
return instance;
}
private User user;
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
setChanged();
notifyObservers();
}
}

I have a instance of a custom JLabel and i want to changes its text in all frames,
A Swing component can only have a single parent. So you actually have two instances of your custom label. So updating the text in one label does not affect the other.
What you can do is create a PlainDocument to contain the text to be shared by multiple JTextFields. Then when the text is the Document is changed all the text fields will be updated.
So in the App class you would have:
private PlainDocument sharedDocument = new PlainDocument();
and you would create a method to access the Document. Maybe something like getSharedDocument().
Then in the form classes you would do something like:
//add(App.getApp().getMyCustomLabel());
JTextField textField = new JTextField( App.getApp().getSharedDocument() );
// customize text field to look like a label
textField.setBorder( null );
textField.setEditable( false );
add( textField );

Unable to resize JPanel in java Swing

I just started using Java Swing, and I was going through the following post: Dynamic fields addition in java/swing form.
I implement the code in this post with some modification, and it worked fine. As mentioned in the post, JPanel is not resizing itself when we add more rows. Can someone throw more light on this issue with easy to understand explanation that how can we resize JPanel as soon as we hit +/- button? Here is the code :
Row class
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextField;
#SuppressWarnings("serial")
public class Row extends JPanel {
private JTextField quantity;
private JTextField item;
private JTextField price;
private JButton plus;
private JButton minus;
private RowList parent;
public Row(String initialQuantity, String initalPrice, String initialItem, RowList list) {
this.parent = list;
this.plus = new JButton(new AddRowAction());
this.minus = new JButton(new RemoveRowAction());
this.quantity = new JTextField(10);
this.item = new JTextField(10);
this.price = new JTextField(10);
this.quantity.setText(initialQuantity);
this.price.setText(initalPrice);
this.item.setText(initialItem);
add(this.plus);
add(this.minus);
add(this.quantity);
add(this.item);
add(this.price);
}
public class AddRowAction extends AbstractAction {
public AddRowAction() {
super("+");
}
public void actionPerformed(ActionEvent e) {
parent.cloneRow(Row.this);
}
}
public class RemoveRowAction extends AbstractAction {
public RemoveRowAction() {
super("-");
}
public void actionPerformed(ActionEvent e) {
parent.removeItem(Row.this);
}
}
public void enableAdd(boolean enabled) {
this.plus.setEnabled(enabled);
}
public void enableMinus(boolean enabled) {
this.minus.setEnabled(enabled);
}
}
RowList class
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class RowList extends JPanel{
private List<Row> rows;
public RowList() {
this.rows = new ArrayList<Row>();
Row initial = new Row("1","0.00","", this);
//addHeaders();
//addGenerateBillButton();
addItem(initial);
}
public void addHeaders(){
JLabel qty = new JLabel("Quantity");
//qty.setBounds(10, 0, 80, 25);
add(qty);
JLabel item = new JLabel("Item");
//item.setBounds(70, 0, 80, 25);
add(item);
JLabel price = new JLabel("Price");
//price.setBounds(120, 0, 80, 25);
add(price);
}
public void addGenerateBillButton(){
JButton billGenerationButton = new JButton("Generate Bill");
add(billGenerationButton);
}
public void cloneRow(Row row) {
Row theClone = new Row("1","0.00","", this);
addItem(theClone);
}
private void addItem(Row row) {
rows.add(row);
add(row);
refresh();
}
public void removeItem(Row entry) {
rows.remove(entry);
remove(entry);
refresh();
}
private void refresh() {
revalidate();
repaint();
if (rows.size() == 1) {
rows.get(0).enableMinus(false);
}
else {
for (Row e : rows) {
e.enableMinus(true);
}
}
}
}
Main class
import javax.swing.JFrame;
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame("Enter Items");
RowList panel = new RowList();
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

You can call the pack() of the frame again.
Try this: Add this in your Row class
public class AddRowAction extends AbstractAction
{
public AddRowAction()
{
super("+");
}
public void actionPerformed(ActionEvent e)
{
parent.cloneRow(Row.this);
((JFrame) SwingUtilities.getRoot(parent)).pack(); // <--- THIS LINE
}
}
public class RemoveRowAction extends AbstractAction
{
public RemoveRowAction()
{
super("-");
}
public void actionPerformed(ActionEvent e)
{
parent.removeItem(Row.this);
((JFrame) SwingUtilities.getRoot(parent)).pack(); // <--- THIS LINE
}
}
You can get the root component (JFrame) using the SwingUtilities.getRoot(comp) from the child component and call the pack() method after your new Row is added to your RowList.
This would resize your JPanel. But your RowList will be horizontal. This is where LayoutManager comes into play.
You can know more about different LayoutManagers here.
To fix this problem, in your RowList panel, set your layout to:
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));

Within your refresh method call doLayout() method after revalidate()

java drop and drag label to join correct image

this code is only allowing me to reject a string the second time to try to drop in a textArea where there is all ready a string.
public GridLayoutTest() {
JFrame frame = new JFrame("GridLayout test");
connection = getConnection();
try {
statement = (PreparedStatement) connection
result = statement.executeQuery();
while (result.next()) {
byte[] image = null;
image = result.getBytes("image");
JPanel cellPanel = new JPanel(new BorderLayout());
cellPanel.add(cellLabel, BorderLayout.NORTH);
cellPanel.add(droplabel, BorderLayout.CENTER);
gridPanel.add(cellPanel);
}
}
catch (SQLException e) {
e.printStackTrace();}
}

So, two things, first...
public void DropTargetTextArea(String string1, String string2) {
Isn't a constructor, it's a method, note the void. This means that it is never getting called. It's also the reason why DropTargetTextArea textArea = new DropTargetTextArea(); works, when you think it shouldn't.
Second, you're not maintaining a reference to the values you pass in to the (want to be) constructor, so you have no means to references them later...
You could try using something like...
private String[] values;
public DropTargetTextArea(String string1, String string2) {
values = new String[]{string1, string2};
DropTarget dropTarget = new DropTarget(this, DnDConstants.ACTION_COPY_OR_MOVE, this, true);
}
And then use something like...
if (values[0].equals(dragContents) || values[1].equals(dragContents)) {
In the drop method.
In your dragEnter, dragOver and dropActionChanged methods you have the oppurtunity to accept or reject the drag action using something like dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE); or dtde.rejectDrag();
Updated with test code
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragSource;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceDropEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceListener;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.io.IOException;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class DragAndDropExample {
public static void main(String[] args) {
ImageIcon ii1 = new ImageIcon("C:\\Users\\Desktop\\home.jpg");
ImageIcon ii = new ImageIcon("C:\\Users\\Desktop\\images (2).jpg");
// Create a frame
JFrame frame = new JFrame("test");
JLabel label = new JLabel(ii);
JLabel label1 = new JLabel(ii1);
JPanel panel = new JPanel(new GridLayout(2, 4, 10, 10));
JLabel testLabel = new DraggableLabel("test");
JLabel testingLabel = new DraggableLabel("testing");
panel.add(testLabel);
panel.add(testingLabel);
panel.add(label);
panel.add(label1);
Component textArea = new DropTargetTextArea("test", "testing");
frame.add(textArea, BorderLayout.CENTER);
frame.add(panel, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public static class DraggableLabel extends JLabel implements DragGestureListener, DragSourceListener {
DragSource dragSource1;
public DraggableLabel(String text) {
setText(text);
dragSource1 = new DragSource();
dragSource1.createDefaultDragGestureRecognizer(this, DnDConstants.ACTION_COPY_OR_MOVE, this);
}
public void dragGestureRecognized(DragGestureEvent evt) {
Transferable transferable = new StringSelection(getText());
dragSource1.startDrag(evt, DragSource.DefaultCopyDrop, transferable, this);
}
public void dragEnter(DragSourceDragEvent evt) {
System.out.println("Drag enter");
}
public void dragOver(DragSourceDragEvent evt) {
System.out.println("Drag over");
}
public void dragExit(DragSourceEvent evt) {
System.out.println("Drag exit");
}
public void dropActionChanged(DragSourceDragEvent evt) {
System.out.println("Drag action changed");
}
public void dragDropEnd(DragSourceDropEvent evt) {
System.out.println("Drag action End");
}
}
public static class DropTargetTextArea extends JLabel implements DropTargetListener {
private String[] values;
public DropTargetTextArea(String string1, String string2) {
values = new String[]{string1, string2};
DropTarget dropTarget = new DropTarget(this, this);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
public void dragEnter(DropTargetDragEvent evt) {
if (!getText().isEmpty()) {
System.out.println("Reject drag enter");
evt.rejectDrag();
} else {
evt.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
}
}
public void dragOver(DropTargetDragEvent evt) {
if (!getText().isEmpty()) {
System.out.println("Reject drag over");
evt.rejectDrag();
} else {
evt.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
}
}
public void dragExit(DropTargetEvent evt) {
System.out.println("Drop exit");
}
public void dropActionChanged(DropTargetDragEvent evt) {
if (!getText().isEmpty()) {
System.out.println("Reject dropActionChanged");
evt.rejectDrag();
} else {
evt.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
}
}
public void drop(DropTargetDropEvent evt) {
if (!getText().isEmpty()) {
evt.rejectDrop();
} else {
try {
Transferable transferable = evt.getTransferable();
if (transferable.isDataFlavorSupported(DataFlavor.stringFlavor)) {
String dragContents = (String) transferable.getTransferData(DataFlavor.stringFlavor);
evt.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
if (values[0].equals(dragContents) || (values[1]).equals(dragContents)) {
System.out.println("Accept Drop");
setText(getText() + " " + dragContents);
evt.getDropTargetContext().dropComplete(true);
} else {
System.out.println("Reject Drop");
}
}
} catch (IOException e) {
evt.rejectDrop();
evt.dropComplete(false);
} catch (UnsupportedFlavorException e) {
}
}
}
}
}

how to drag and drop files from a directory in java

I want to implement dragging and dropping of files from a directory such as someones hard drive but can't figure out how to do it. I've read the java api but it talks of color pickers and dragging and dropping between lists but how to drag files from a computers file system and drop into my application. I tried writing the transferhandler class and a mouse event for when the drag starts but nothing seems to work. Now I'm back to just having my JFileChooser set so drag has been enabled but how to drop?
Any info or point in the right direction greatly appreciated.
import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.swing.BorderFactory;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.filechooser.FileFilter;
public class FileChooserDemo
extends JPanel
implements ActionListener
{
JLabel selectedFileLabel;
JList selectedFilesList;
JLabel returnCodeLabel;
public FileChooserDemo()
{
super();
createContent();
}
void initFrameContent()
{
JPanel closePanel = new JPanel();
add(closePanel, BorderLayout.SOUTH);
}
private void createContent()
{
setLayout(new BorderLayout());
JPanel NorthPanel = new JPanel();
JMenuBar menuBar = new JMenuBar();
JMenu menu = new JMenu("File");
JMenuItem quit = new JMenuItem("Quit");
menuBar.add(menu);
menu.add(quit);
NorthPanel.add(menu,BorderLayout.NORTH);
JPanel buttonPanel = new JPanel(new GridLayout(7,1 ));
JButton openButton = new JButton("Open...");
openButton.setActionCommand("OPEN");
openButton.addActionListener(this);
buttonPanel.add(openButton);
JButton saveButton = new JButton("Save...");
saveButton.setActionCommand("SAVE");
saveButton.addActionListener(this);
buttonPanel.add(saveButton);
JButton delete = new JButton("Delete");
delete.addActionListener(this);
delete.setActionCommand("DELETE");
buttonPanel.add(delete);
add(buttonPanel, BorderLayout.WEST);
// create a panel to display the selected file(s) and the return code
JPanel displayPanel = new JPanel(new BorderLayout());
selectedFileLabel = new JLabel("-");
selectedFileLabel.setBorder(BorderFactory.createTitledBorder
("Selected File/Directory "));
displayPanel.add(selectedFileLabel, BorderLayout.NORTH);
selectedFilesList = new JList();
JScrollPane sp = new JScrollPane(selectedFilesList);
sp.setBorder(BorderFactory.createTitledBorder("Selected Files "));
MouseListener listener = new MouseAdapter()
{
public void mousePressed(MouseEvent me)
{
JComponent comp = (JComponent) me.getSource();
TransferHandler handler = comp.getTransferHandler();
handler.exportAsDrag(comp, me, TransferHandler.MOVE);
}
};
selectedFilesList.addMouseListener(listener);
displayPanel.add(sp);
returnCodeLabel = new JLabel("");
returnCodeLabel.setBorder(BorderFactory.createTitledBorder("Return Code"));
displayPanel.add(returnCodeLabel, BorderLayout.SOUTH);
add(displayPanel);
}
public void actionPerformed(ActionEvent e)
{
int option = 0;
File selectedFile = null;
File[] selectedFiles = new File[0];
if (e.getActionCommand().equals("CLOSE"))
{
System.exit(0);
}
else if (e.getActionCommand().equals("OPEN"))
{
JFileChooser chooser = new JFileChooser();
chooser.setDragEnabled(true);
chooser.setMultiSelectionEnabled(true);
option = chooser.showOpenDialog(this);
selectedFiles = chooser.getSelectedFiles();
}
else if (e.getActionCommand().equals("SAVE"))
{
JFileChooser chooser = new JFileChooser();
option = chooser.showSaveDialog(this);
selectedFiles = chooser.getSelectedFiles();
}
// display the selection and return code
if (selectedFile != null)
selectedFileLabel.setText(selectedFile.toString());
else
selectedFileLabel.setText("null");
DefaultListModel listModel = new DefaultListModel();
for (int i =0; i < selectedFiles.length; i++)
listModel.addElement(selectedFiles[i]);
selectedFilesList.setModel(listModel);
returnCodeLabel.setText(Integer.toString(option));
}
public static void main(String[] args)
{
SwingUtilities.invokeLater
(new Runnable()
{
public void run()
{
FileChooserDemo app = new FileChooserDemo();
app.initFrameContent();
JFrame frame = new JFrame("LoquetUP");
frame.getContentPane().add(app);
frame.setDefaultCloseOperation(3);
frame.setSize(600,400);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
//frame.pack();
frame.setVisible(true);
}
});
}
}

This is my take on the idea. I've used the "traditional" drag and drop API in this example. It has some extra "paint" tweaks just to show off what you might be able to do.
This example doesn't scan folders dropped onto it, so any folder will only register as a single file, but I'm sure you can work it out
public class TestDragNDropFiles {
public static void main(String[] args) {
new TestDragNDropFiles();
}
public TestDragNDropFiles() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new DropPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class DropPane extends JPanel {
private DropTarget dropTarget;
private DropTargetHandler dropTargetHandler;
private Point dragPoint;
private boolean dragOver = false;
private BufferedImage target;
private JLabel message;
public DropPane() {
try {
target = ImageIO.read(new File("target.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
setLayout(new GridBagLayout());
message = new JLabel();
message.setFont(message.getFont().deriveFont(Font.BOLD, 24));
add(message);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
protected DropTarget getMyDropTarget() {
if (dropTarget == null) {
dropTarget = new DropTarget(this, DnDConstants.ACTION_COPY_OR_MOVE, null);
}
return dropTarget;
}
protected DropTargetHandler getDropTargetHandler() {
if (dropTargetHandler == null) {
dropTargetHandler = new DropTargetHandler();
}
return dropTargetHandler;
}
#Override
public void addNotify() {
super.addNotify();
try {
getMyDropTarget().addDropTargetListener(getDropTargetHandler());
} catch (TooManyListenersException ex) {
ex.printStackTrace();
}
}
#Override
public void removeNotify() {
super.removeNotify();
getMyDropTarget().removeDropTargetListener(getDropTargetHandler());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (dragOver) {
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(new Color(0, 255, 0, 64));
g2d.fill(new Rectangle(getWidth(), getHeight()));
if (dragPoint != null && target != null) {
int x = dragPoint.x - 12;
int y = dragPoint.y - 12;
g2d.drawImage(target, x, y, this);
}
g2d.dispose();
}
}
protected void importFiles(final List files) {
Runnable run = new Runnable() {
#Override
public void run() {
message.setText("You dropped " + files.size() + " files");
}
};
SwingUtilities.invokeLater(run);
}
protected class DropTargetHandler implements DropTargetListener {
protected void processDrag(DropTargetDragEvent dtde) {
if (dtde.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
dtde.acceptDrag(DnDConstants.ACTION_COPY);
} else {
dtde.rejectDrag();
}
}
#Override
public void dragEnter(DropTargetDragEvent dtde) {
processDrag(dtde);
SwingUtilities.invokeLater(new DragUpdate(true, dtde.getLocation()));
repaint();
}
#Override
public void dragOver(DropTargetDragEvent dtde) {
processDrag(dtde);
SwingUtilities.invokeLater(new DragUpdate(true, dtde.getLocation()));
repaint();
}
#Override
public void dropActionChanged(DropTargetDragEvent dtde) {
}
#Override
public void dragExit(DropTargetEvent dte) {
SwingUtilities.invokeLater(new DragUpdate(false, null));
repaint();
}
#Override
public void drop(DropTargetDropEvent dtde) {
SwingUtilities.invokeLater(new DragUpdate(false, null));
Transferable transferable = dtde.getTransferable();
if (dtde.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
dtde.acceptDrop(dtde.getDropAction());
try {
List transferData = (List) transferable.getTransferData(DataFlavor.javaFileListFlavor);
if (transferData != null && transferData.size() > 0) {
importFiles(transferData);
dtde.dropComplete(true);
}
} catch (Exception ex) {
ex.printStackTrace();
}
} else {
dtde.rejectDrop();
}
}
}
public class DragUpdate implements Runnable {
private boolean dragOver;
private Point dragPoint;
public DragUpdate(boolean dragOver, Point dragPoint) {
this.dragOver = dragOver;
this.dragPoint = dragPoint;
}
#Override
public void run() {
DropPane.this.dragOver = dragOver;
DropPane.this.dragPoint = dragPoint;
DropPane.this.repaint();
}
}
}
}

You need to experiment with Drag & Drop and see exactly what flavors are available when you try to drag files. If you do this in your custom TransferHandler you'll be pleasantly surprised one Flavor is the DataFlavor.javaFileListFlavor, which indicates that the item can be used simply as a List. Try it and you'll see that it works!
Note on review of your posted code, I don't see any code for your attempt at using a TransferHandler, so it is hard to say what you could be doing wrong here.
Edit 1
You seem to be trying to use a MouseListener for your drag and drop, and I'm not familiar with this usage. Can you show a reference to a tutorial that tells you to do this?
Edit 2
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.swing.*;
#SuppressWarnings("serial")
public class FileDragDemo extends JPanel {
private JList list = new JList();
public FileDragDemo() {
list.setDragEnabled(true);
list.setTransferHandler(new FileListTransferHandler(list));
add(new JScrollPane(list));
}
private static void createAndShowGui() {
FileDragDemo mainPanel = new FileDragDemo();
JFrame frame = new JFrame("FileDragDemo");
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();
}
});
}
}
#SuppressWarnings("serial")
class FileListTransferHandler extends TransferHandler {
private JList list;
public FileListTransferHandler(JList list) {
this.list = list;
}
public int getSourceActions(JComponent c) {
return COPY_OR_MOVE;
}
public boolean canImport(TransferSupport ts) {
return ts.isDataFlavorSupported(DataFlavor.javaFileListFlavor);
}
public boolean importData(TransferSupport ts) {
try {
#SuppressWarnings("rawtypes")
List data = (List) ts.getTransferable().getTransferData(
DataFlavor.javaFileListFlavor);
if (data.size() < 1) {
return false;
}
DefaultListModel listModel = new DefaultListModel();
for (Object item : data) {
File file = (File) item;
listModel.addElement(file);
}
list.setModel(listModel);
return true;
} catch (UnsupportedFlavorException e) {
return false;
} catch (IOException e) {
return false;
}
}
}

Editable JTableHeader [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Accessing a JTextField in JTableHeader
How to make JTableHeader as editable. F.e. i make ColumnHeader as JTextField. What must i do to make JTextField editable. See the example:
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import java.awt.event.*;
public class Test extends JFrame {
String[][] cellValues = { { "v00", "v01", "v02" }, { "v10", "v11", "v12" },
{ "v20", "v21", "v22" }, { "v30", "v31", "v32" },
{ "v40", "v41", "v42" }, { "v50", "v51", "v52" } };
String[] columnNames = { "v00", "v01", "v02" };
javax.swing.JTable jTable1 = new javax.swing.JTable(cellValues, columnNames);
public Test() {
try {
jbInit();
} catch (Exception e) {
e.printStackTrace();
}
}
private void jbInit() throws Exception {
this.getContentPane().add(new JScrollPane(jTable1), null);
for (int i = 0; i < 3; i++)
jTable1.getColumnModel().getColumn(i)
.setHeaderRenderer(new Renderer());
}
public static void main(String[] args) {
Test frame = new Test();
frame.addWindowListener(new java.awt.event.WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
frame.pack();
frame.setVisible(true);
}
}
class Renderer extends JPanel implements TableCellRenderer {
JLabel label = new JLabel(" ");
JTextField field = new JTextField("%");
public Renderer() {
super(new BorderLayout());
add(label, BorderLayout.NORTH);
add(field, BorderLayout.CENTER);
setBorder(BorderFactory.createEtchedBorder());
}
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
label.setText(value.toString());
return (JComponent) this;
}
public String toString() {
return label.toString();
}
public void setText(String text) {
label.setText(text);
}
}

Here's a simple approach for making editable headers (no custom renderers or UIs required):
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.table.*;
public class JTableEditableHeaderDemo implements Runnable
{
private JTable table;
private JTableHeader header;
private JPopupMenu renamePopup;
private JTextField text;
private TableColumn column;
public static void main(String[] args)
{
SwingUtilities.invokeLater(new JTableEditableHeaderDemo());
}
public JTableEditableHeaderDemo()
{
table = new JTable(10, 5);
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
table.setPreferredScrollableViewportSize(table.getPreferredSize());
header = table.getTableHeader();
header.addMouseListener(new MouseAdapter(){
#Override
public void mouseClicked(MouseEvent event)
{
if (event.getClickCount() == 2)
{
editColumnAt(event.getPoint());
}
}
});
text = new JTextField();
text.setBorder(null);
text.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
renameColumn();
}
});
renamePopup = new JPopupMenu();
renamePopup.setBorder(new MatteBorder(0, 1, 1, 1, Color.DARK_GRAY));
renamePopup.add(text);
}
public void run()
{
JFrame f = new JFrame("Double-click header to edit");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new JScrollPane(table));
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private void editColumnAt(Point p)
{
int columnIndex = header.columnAtPoint(p);
if (columnIndex != -1)
{
column = header.getColumnModel().getColumn(columnIndex);
Rectangle columnRectangle = header.getHeaderRect(columnIndex);
text.setText(column.getHeaderValue().toString());
renamePopup.setPreferredSize(
new Dimension(columnRectangle.width, columnRectangle.height - 1));
renamePopup.show(header, columnRectangle.x, 0);
text.requestFocusInWindow();
text.selectAll();
}
}
private void renameColumn()
{
column.setHeaderValue(text.getText());
renamePopup.setVisible(false);
header.repaint();
}
}

There is a complete solution under the following link, looks quite good at the first sight!
How do I create a JTable with editable headers?