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Drag'n drop files from the OS to Java application (Swing) - java

Let me start by saying that I have been reading the drag'n drop tutorial and similar questions asked on SO, but unfortunately I have only gotten more confused about this matter. What I want to achieve is relatively simple so I am surprised that it got me in so much trouble already. I am writing a small utility application which will consolidate a bunch of result files (custom defined xml-type) into a large tab-separated text file. Most of the functionality is already coded, however I wanted to make a decent GUI for it.
What I want is to be able to drag'n drop files into a component (for instance JTextArea) in a nice and gracious way (read: not full paths, but instead a small icon and name). I would like to be able to supply a JFileChooser to browse for files as well. I will then parse the files sequentially to produce the matrix I want.
What I have learned so far is that the framework is already there however any additional functionality needs to be custom built. I have created a test GUI in Netbeans and tried to drag a bunch of files onto a JTextArea, but they appear as file paths, and admittedly it looks very ugly.
I would really appreciate any tips and guidance on how to solve (or clarify) this problem in a neat way. Note that I do intend to use the software on multiple different OS (Mac,Win and Linux).
EDIT: the code I have so far is based on one of the examples from Sun tutorials and is as follows
import java.awt.datatransfer.*;
import java.awt.event.*;
import java.awt.*;
import java.io.*;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.border.TitledBorder;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.text.*;
public class ConsolidatorDemo extends JPanel implements ActionListener {
private static final long serialVersionUID = -4487732343062917781L;
JFileChooser fc;
JButton clear;
JTextArea dropZone, console;
JSplitPane childSplitPane, parentSplitPane;
PrintStream ps;
public ConsolidatorDemo() {
super(new BorderLayout());
fc = new JFileChooser();;
fc.setMultiSelectionEnabled(true);
fc.setDragEnabled(true);
fc.setControlButtonsAreShown(false);
fc.setFileSelectionMode(JFileChooser.FILES_ONLY);
JPanel fcPanel = new JPanel(new BorderLayout());
fcPanel.add(fc, BorderLayout.CENTER);
clear = new JButton("Clear All");
clear.addActionListener(this);
JPanel buttonPanel = new JPanel(new BorderLayout());
buttonPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
buttonPanel.add(clear, BorderLayout.LINE_END);
JPanel leftUpperPanel = new JPanel(new BorderLayout());
leftUpperPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
leftUpperPanel.add(fcPanel, BorderLayout.CENTER);
leftUpperPanel.add(buttonPanel, BorderLayout.PAGE_END);
JScrollPane leftLowerPanel = new javax.swing.JScrollPane();
leftLowerPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
dropZone = new JTextArea();
dropZone.setColumns(20);
dropZone.setLineWrap(true);
dropZone.setRows(5);
dropZone.setDragEnabled(true);
dropZone.setDropMode(javax.swing.DropMode.INSERT);
dropZone.setBorder(new TitledBorder("Selected files/folders"));
leftLowerPanel.setViewportView(dropZone);
childSplitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
leftUpperPanel, leftLowerPanel);
childSplitPane.setDividerLocation(400);
childSplitPane.setPreferredSize(new Dimension(480, 650));
console = new JTextArea();
console.setColumns(40);
console.setLineWrap(true);
console.setBorder(new TitledBorder("Console"));
parentSplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
childSplitPane, console);
parentSplitPane.setDividerLocation(480);
parentSplitPane.setPreferredSize(new Dimension(800, 650));
add(parentSplitPane, BorderLayout.CENTER);
}
public void setDefaultButton() {
getRootPane().setDefaultButton(clear);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == clear) {
dropZone.setText("");
}
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
try {
//UIManager.setLookAndFeel("de.javasoft.plaf.synthetica.SyntheticaBlackStarLookAndFeel");
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
}catch (Exception e){
e.printStackTrace();
}
//Create and set up the window.
JFrame frame = new JFrame("Consolidator!");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//Create and set up the menu bar and content pane.
ConsolidatorDemo demo = new ConsolidatorDemo();
demo.setOpaque(true); //content panes must be opaque
frame.setContentPane(demo);
//Display the window.
frame.pack();
frame.setVisible(true);
demo.setDefaultButton();
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}

here's a quick snippet to import the actual Files into a JList (as opposed to importing its String representation into a text component) and use a custom renderer to present it nicely. It's adapted from the BasicDnD (in the tutorial):
fileDropper = new JList(new DefaultListModel());
fileDropper.setDragEnabled(true);
leftLowerPanel.setViewportView(fileDropper);
TransferHandler handler = new TransferHandler() {
#Override
public boolean canImport(TransferHandler.TransferSupport info) {
// we only import FileList
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
return false;
}
return true;
}
#Override
public boolean importData(TransferHandler.TransferSupport info) {
if (!info.isDrop()) {
return false;
}
// Check for FileList flavor
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
displayDropLocation("List doesn't accept a drop of this type.");
return false;
}
// Get the fileList that is being dropped.
Transferable t = info.getTransferable();
List<File> data;
try {
data = (List<File>)t.getTransferData(DataFlavor.javaFileListFlavor);
}
catch (Exception e) { return false; }
DefaultListModel model = (DefaultListModel) fileDropper.getModel();
for (File file : data) {
model.addElement(file);
}
return true;
}
private void displayDropLocation(String string) {
System.out.println(string);
}
};
fileDropper.setTransferHandler(handler);
fileDropper.setCellRenderer(new DefaultListRenderer(
StringValues.FILE_NAME, IconValues.FILE_ICON));
Couldn't resist to showing SwingX renderer config :-) In core java, you would do it manually, something like
class MyRenderer extends DefaultListCellRenderer {
#Override
public Component getListCellRendererComponent(...) {
super.getList...
if (value instanceof File) {
setText(FileSystemView.getFileSystemView().getDisplayName(value);
setIcon(FileSystemView.getFileSystemView().getSystemIcon(value);
}
return this;
}
}

This is effectively kleopatra's answer1 (with a few trivial changes, not necessarily for the better), ..with a screenshot!
import java.awt.datatransfer.*;
import java.awt.event.*;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.io.*;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.border.TitledBorder;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.filechooser.FileSystemView;
import javax.swing.text.*;
import java.util.List;
public class ConsolidatorDemo extends JPanel implements ActionListener {
private static final long serialVersionUID = -4487732343062917781L;
JFileChooser fc;
JButton clear;
JTextArea console;
JList dropZone;
DefaultListModel listModel;
JSplitPane childSplitPane, parentSplitPane;
PrintStream ps;
public ConsolidatorDemo() {
super(new BorderLayout());
fc = new JFileChooser();;
fc.setMultiSelectionEnabled(true);
fc.setDragEnabled(true);
fc.setControlButtonsAreShown(false);
fc.setFileSelectionMode(JFileChooser.FILES_ONLY);
JPanel fcPanel = new JPanel(new BorderLayout());
fcPanel.add(fc, BorderLayout.CENTER);
clear = new JButton("Clear All");
clear.addActionListener(this);
JPanel buttonPanel = new JPanel(new BorderLayout());
buttonPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
buttonPanel.add(clear, BorderLayout.LINE_END);
JPanel leftUpperPanel = new JPanel(new BorderLayout());
leftUpperPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
leftUpperPanel.add(fcPanel, BorderLayout.CENTER);
leftUpperPanel.add(buttonPanel, BorderLayout.PAGE_END);
JScrollPane leftLowerPanel = new javax.swing.JScrollPane();
leftLowerPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
listModel = new DefaultListModel();
dropZone = new JList(listModel);
dropZone.setCellRenderer(new FileCellRenderer());
dropZone.setTransferHandler(new ListTransferHandler(dropZone));
dropZone.setDragEnabled(true);
dropZone.setDropMode(javax.swing.DropMode.INSERT);
dropZone.setBorder(new TitledBorder("Selected files/folders"));
leftLowerPanel.setViewportView(new JScrollPane(dropZone));
childSplitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
leftUpperPanel, leftLowerPanel);
childSplitPane.setDividerLocation(400);
childSplitPane.setPreferredSize(new Dimension(480, 650));
console = new JTextArea();
console.setColumns(40);
console.setLineWrap(true);
console.setBorder(new TitledBorder("Console"));
parentSplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
childSplitPane, console);
parentSplitPane.setDividerLocation(480);
parentSplitPane.setPreferredSize(new Dimension(800, 650));
add(parentSplitPane, BorderLayout.CENTER);
}
public void setDefaultButton() {
getRootPane().setDefaultButton(clear);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == clear) {
listModel.clear();
}
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
try {
//UIManager.setLookAndFeel("de.javasoft.plaf.synthetica.SyntheticaBlackStarLookAndFeel");
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
}catch (Exception e){
e.printStackTrace();
}
//Create and set up the window.
JFrame frame = new JFrame("Consolidator!");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//Create and set up the menu bar and content pane.
ConsolidatorDemo demo = new ConsolidatorDemo();
demo.setOpaque(true); //content panes must be opaque
frame.setContentPane(demo);
//Display the window.
frame.pack();
frame.setVisible(true);
demo.setDefaultButton();
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
class FileCellRenderer extends DefaultListCellRenderer {
public Component getListCellRendererComponent(JList list,
Object value,
int index,
boolean isSelected,
boolean cellHasFocus) {
Component c = super.getListCellRendererComponent(
list,value,index,isSelected,cellHasFocus);
if (c instanceof JLabel && value instanceof File) {
JLabel l = (JLabel)c;
File f = (File)value;
l.setIcon(FileSystemView.getFileSystemView().getSystemIcon(f));
l.setText(f.getName());
l.setToolTipText(f.getAbsolutePath());
}
return c;
}
}
class ListTransferHandler extends TransferHandler {
private JList list;
ListTransferHandler(JList list) {
this.list = list;
}
#Override
public boolean canImport(TransferHandler.TransferSupport info) {
// we only import FileList
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
return false;
}
return true;
}
#Override
public boolean importData(TransferHandler.TransferSupport info) {
if (!info.isDrop()) {
return false;
}
// Check for FileList flavor
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
displayDropLocation("List doesn't accept a drop of this type.");
return false;
}
// Get the fileList that is being dropped.
Transferable t = info.getTransferable();
List<File> data;
try {
data = (List<File>)t.getTransferData(DataFlavor.javaFileListFlavor);
}
catch (Exception e) { return false; }
DefaultListModel model = (DefaultListModel) list.getModel();
for (Object file : data) {
model.addElement((File)file);
}
return true;
}
private void displayDropLocation(String string) {
System.out.println(string);
}
}
I was busy writing an answer when I noticed she had already posted one. Since my TransferHandler was very broken, I used hers. Though I used my version of the list cell renderer, which does not seem to capture the subtlety of what she was suggesting. I was also getting compilation errors on the mention of List (given the compiler was assuming I meant an AWT list. I only realized what was happening after I'd changed several of the List<File> type statements to be non-generic - I think most of them are now changed back.

Here is the code without console and extra button
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.PrintStream;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.DefaultListCellRenderer;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import javax.swing.TransferHandler;
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.border.TitledBorder;
import javax.swing.filechooser.FileSystemView;
public class ConsolidatorDemo extends JPanel implements ActionListener {
private static final long serialVersionUID = -4487732343062917781L;
// JFileChooser fc;
JButton clear,compare;
JTextArea fc;
JList dropZone;
DefaultListModel listModel;
JSplitPane childSplitPane, parentSplitPane;
PrintStream ps;
public ConsolidatorDemo() {
super(new BorderLayout());
/* fc = new JFileChooser();;
fc.setMultiSelectionEnabled(true);
fc.setDragEnabled(true);
fc.setControlButtonsAreShown(false);
fc.setFileSelectionMode(JFileChooser.FILES_ONLY);*/
fc= new JTextArea();
fc.setText("Rules:\n1. drop old html first.\n2. drop new html.\n3. drop output folder.\n4. click compare button.\n5. Check output in the output.txt file.\nEnd");
fc.setEditable(false);
JPanel fcPanel = new JPanel(new BorderLayout());
fcPanel.add(fc, BorderLayout.CENTER);
compare = new JButton("Compare");
compare.addActionListener(this);
JPanel buttonPanel1 = new JPanel(new BorderLayout());
buttonPanel1.setBorder(BorderFactory.createEmptyBorder(1,1,1,1));
buttonPanel1.add(compare, BorderLayout.LINE_END);
clear = new JButton("Clear All");
clear.addActionListener(this);
JPanel buttonPanel = new JPanel(new BorderLayout());
buttonPanel.setBorder(BorderFactory.createEmptyBorder(1,1,1,1));
buttonPanel.add(clear, BorderLayout.LINE_END);
JPanel leftUpperPanel = new JPanel(new BorderLayout());
leftUpperPanel.setBorder(BorderFactory.createEmptyBorder(3,3,3,3));
leftUpperPanel.add(fcPanel, BorderLayout.CENTER);
leftUpperPanel.add(buttonPanel1, BorderLayout.LINE_END);
leftUpperPanel.add(buttonPanel, BorderLayout.PAGE_END);
JScrollPane leftLowerPanel = new javax.swing.JScrollPane();
leftLowerPanel.setBorder(BorderFactory.createEmptyBorder(3,3,3,3));
listModel = new DefaultListModel();
dropZone = new JList(listModel);
dropZone.setCellRenderer(new FileCellRenderer());
dropZone.setTransferHandler(new ListTransferHandler(dropZone));
dropZone.setDragEnabled(true);
dropZone.setDropMode(javax.swing.DropMode.INSERT);
dropZone.setBorder(new TitledBorder("Drag and drop files here"));
leftLowerPanel.setViewportView(new JScrollPane(dropZone));
childSplitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, leftLowerPanel,leftUpperPanel);
childSplitPane.setDividerLocation(200);//400
childSplitPane.setPreferredSize(new Dimension(300, 400));//480, 650
/*console = new JTextArea();
console.setColumns(40);
console.setLineWrap(true);
console.setBorder(new TitledBorder("Console"));
parentSplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
childSplitPane, console);
parentSplitPane.setDividerLocation(480);
parentSplitPane.setPreferredSize(new Dimension(800, 650));*/
add(childSplitPane, BorderLayout.CENTER);
}
public void setDefaultButton() {
getRootPane().setDefaultButton(clear);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == clear) {
listModel.clear();
}else if (e.getSource() == compare) {
//our function
}
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
try {
//UIManager.setLookAndFeel("de.javasoft.plaf.synthetica.SyntheticaBlackStarLookAndFeel");
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
}catch (Exception e){
e.printStackTrace();
}
//Create and set up the window.
JFrame frame = new JFrame("Bill of materials Comparer");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//Create and set up the menu bar and content pane.
ConsolidatorDemo demo = new ConsolidatorDemo();
demo.setOpaque(true); //content panes must be opaque
frame.setContentPane(demo);
//Display the window.
frame.pack();
frame.setVisible(true);
demo.setDefaultButton();
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
class FileCellRenderer extends DefaultListCellRenderer {
public Component getListCellRendererComponent(JList list,Object value,int index,boolean isSelected,boolean cellHasFocus) {
Component c = super.getListCellRendererComponent(list,value,index,isSelected,cellHasFocus);
if (c instanceof JLabel && value instanceof File) {
JLabel l = (JLabel)c;
File f = (File)value;
l.setIcon(FileSystemView.getFileSystemView().getSystemIcon(f));
l.setText(f.getName());
//l.setText(f.getAbsolutePath());
l.setToolTipText(f.getAbsolutePath());
}
return c;
}
}
class ListTransferHandler extends TransferHandler {
private JList list;
ListTransferHandler(JList list) {
this.list = list;
}
#Override
public boolean canImport(TransferHandler.TransferSupport info) {
// we only import FileList
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
return false;
}
return true;
}
#Override
public boolean importData(TransferHandler.TransferSupport info) {
if (!info.isDrop()) {
return false;
}
// Check for FileList flavor
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
displayDropLocation("List doesn't accept a drop of this type.");
return false;
}
// Get the fileList that is being dropped.
Transferable t = info.getTransferable();
List<File> data;
try {
data = (List<File>)t.getTransferData(DataFlavor.javaFileListFlavor);
}
catch (Exception e) { return false; }
DefaultListModel model = (DefaultListModel) list.getModel();
for (Object file : data) {
model.addElement((File)file);
}
return true;
}
private void displayDropLocation(String string) {
System.out.println(string);
}
}

Related

I want do display a text filed in a popup. When popup is completly over the application frame (MediumWeightPopup) - all works fine, but when a part of popup is outside of frame (HeavyWeightPopup) it cannot be focused. In this case caret is invisible and no text input is possible.
Here is my code:
import java.awt.BorderLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.Popup;
import javax.swing.PopupFactory;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
public class PopupTest {
public static void main(String[] args) {
JFrame frm = new JFrame("Popup test");
JPanel p = new JPanel();
p.addMouseListener(new MouseAdapter() {
Popup pop;
#Override
public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isRightMouseButton(e)) {
if (pop != null) {
pop.hide();
}
JPanel popupPanel = new JPanel(new BorderLayout());
JTextField field = new JTextField(20);
popupPanel.add(field);
pop = PopupFactory.getSharedInstance().getPopup(p, popupPanel, e.getXOnScreen(), e.getYOnScreen());
pop.show();
System.out.println("Popup type: " + pop.getClass().getName());
System.out.println("Can get focus? " + field.requestFocusInWindow());
}
}
});
frm.add(p);
frm.setSize(500, 300);
frm.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frm.setLocationRelativeTo(null);
frm.setVisible(true);
}
}
On right click near to right border of window I get a non-focusable text field. The same problem I get with any other component in popup that allows key control (for example JTable).
How can I focus a component in a HeavyWeightPopup?

I also struggled with this years ago. I can't figure out how to give initial focus to a component on the popup. Here are some of my questions/observations:
What is the Popup class used for?
I always thought that a Popup should have some basic functionality, such as the pupup should close when:
a) the escape key is pressed
b) the popup loses focus
The popup class provides none of the above functionality and in fact seems to require some obscure code to even get the keyboard focus to work properly.
Using a JWindow seems to provide the same functionality as a Popup.
JPopupMenu seems to support both of the above requirements.
Run the following program:
a) click on each of the buttons
b) click on an empty part of the frame
It appears to me that whenever you need a "popup" you should use a JPopupMenu.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class PopupTest extends JFrame
{
String[] numbers = { "one", "two", "three", "four", "five" };
public PopupTest()
{
getContentPane().setLayout( new FlowLayout() );
getContentPane().setBackground(Color.YELLOW);
JButton popup = new JButton("Popup as Popup");
popup.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
popupPopup(e);
}
});
getContentPane().add(popup);
JButton window = new JButton("Window as Popup");
window.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
windowPopup(e);
}
});
getContentPane().add(window);
JButton menu = new JButton("PopupMenu as Popup");
menu.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
menuPopup(e);
}
});
getContentPane().add(menu);
}
private void popupPopup(ActionEvent e)
{
JList list = new JList(numbers);
list.setSelectedIndex(0);
PopupFactory factory = PopupFactory.getSharedInstance();
Popup popup = factory.getPopup(this, list, getLocation().x, getLocation().y+100);
//popup.show();
Window window = SwingUtilities.windowForComponent(list);
if (window != null)
{
window.setFocusableWindowState(true);
}
popup.show();
KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent(list);
}
private void windowPopup(ActionEvent e)
{
JList list = new JList(numbers);
list.setSelectedIndex(0);
JWindow window = new JWindow(this);
window.getContentPane().add(list);
window.pack();
window.setVisible(true);
window.setLocation(getLocation().x + 200, getLocation().y+100);
window.addWindowListener( new WindowAdapter()
{
public void windowDeactivated(WindowEvent e)
{
System.out.println("deactivated");
}
});
}
private void menuPopup(ActionEvent e)
{
JList list = new JList(numbers);
list.setSelectedIndex(0);
JPopupMenu menu = new JPopupMenu();
menu.add( new JTextField(10) );
menu.add( list );
menu.show((Component)e.getSource(), 0, 100);
}
private static void createAndShowGUI()
{
JFrame frame = new PopupTest();
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
frame.setSize(500, 200);
frame.setLocationRelativeTo( null );
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater( () -> createAndShowGUI() );
/*
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
*/
}
}
Edit:
Based on Sergiy's answer, this code was close to working. The difference in the popupPopup() method is that the show() method needs to be invoked AFTER the window is made focusable. Code updated to reflect this change.

Source code analyse brought me another solution
pop = PopupFactory.getSharedInstance().getPopup(p, popupPanel, e.getXOnScreen(), e.getYOnScreen());
// some new stuff
Window win = SwingUtilities.windowForComponent(popupPanel);
if (win instanceof JWindow && win.getType() == Window.Type.POPUP) {
win.setFocusableWindowState(true);
}
// continue old stuff
pop.show();
So the complete example looks like
import java.awt.BorderLayout;
import java.awt.Window;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JWindow;
import javax.swing.Popup;
import javax.swing.PopupFactory;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
public class PopupTest {
public static void main(String[] args) {
JFrame frm = new JFrame("Popup test");
JPanel p = new JPanel();
p.addMouseListener(new MouseAdapter() {
Popup pop;
#Override
public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isRightMouseButton(e)) {
if (pop != null) {
pop.hide();
}
JPanel popupPanel = new JPanel(new BorderLayout());
JTextField field = new JTextField(20);
popupPanel.add(field);
pop = PopupFactory.getSharedInstance().getPopup(p, popupPanel, e.getXOnScreen(), e.getYOnScreen());
Window win = SwingUtilities.windowForComponent(popupPanel);
if (win instanceof JWindow && win.getType() == Window.Type.POPUP) {
win.setFocusableWindowState(true);
}
pop.show();
System.out.println("Popup type: " + pop.getClass().getName());
System.out.println("Can get focus? " + field.requestFocusInWindow());
}
}
});
frm.add(p);
frm.setSize(500, 300);
frm.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frm.setLocationRelativeTo(null);
frm.setVisible(true);
}
}
Interesting: the call field.requestFocusInWindow() still returns false, but field gets focus anyway.
BTW: this solution is also better for me because in my real code I get the Popup from a JComboBox (my goal is to create JTableComboBox with a table in popup and an optional filter field on top of the table).

I'm writing a GUI using Swing. I have a custom written JComboBox using a ListCellRenderer and a BasicComboBoxEditor.
In my getListCellRendererComponent() method I change the color of the the list based on whether the item is "selected" (mouse is hovering above), which is nice and all, but I don't want the selection to change background color once a choice is made, which it currently does.
The first picture shows how the interface looks before a selection is made, and the second one shows how it looks after.
QUESTION
How do I change the background of the "selection" to the "stockColor"?
MCVE
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.util.Vector;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.ListCellRenderer;
import javax.swing.plaf.basic.BasicComboBoxEditor;
public class TFComboBox extends JComboBox{
public static void main(String[] args){
createAndShowGUI();
}
public static void createAndShowGUI(){
JFrame frame = new JFrame("MCVE");
JPanel pane = new JPanel(new BorderLayout());
TFComboBox cb = new TFComboBox();
boolean[] tf = {true, false};
cb.addItems(tf);
JButton b = new JButton("Click me!");
pane.add(cb, BorderLayout.CENTER);
pane.add(b, BorderLayout.LINE_END);
frame.add(pane);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
private DefaultComboBoxModel model;
private Vector<Boolean> comboBoxItems;
private JComboBox comboBox;
public TFComboBox(){
comboBoxItems = new Vector<Boolean>();
comboBoxItems.add(Boolean.TRUE);
comboBoxItems.add(Boolean.FALSE);
comboBox = new JComboBox(comboBoxItems);
model = new DefaultComboBoxModel();
setModel(model);
setRenderer(new TrueFalseComboRenderer());
setEditor(new TrueFalseComboEditor());
}
public void addItems(boolean[] items){
for(boolean anItem : items){
model.addElement(anItem);
}
}
}
class TrueFalseComboRenderer extends JPanel implements ListCellRenderer {
private JLabel labelItem = new JLabel();
private Color stockColor = labelItem.getBackground();
public TrueFalseComboRenderer(){
setLayout(new BorderLayout());
labelItem.setOpaque(true);
labelItem.setHorizontalAlignment(JLabel.CENTER);
add(labelItem);
setBackground(Color.LIGHT_GRAY);
}
#Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
boolean tempValue = (boolean) value;
labelItem.setText(Boolean.toString(tempValue));
if(isSelected){
labelItem.setBackground(stockColor.darker());
labelItem.setForeground(Color.WHITE);
} else {
labelItem.setBackground(stockColor);
labelItem.setForeground(Color.BLACK);
}
return this;
}
}
class TrueFalseComboEditor extends BasicComboBoxEditor {
private JLabel labelItem = new JLabel();
private JPanel panel = new JPanel();
private Object selectedItem;
public TrueFalseComboEditor() {
labelItem.setOpaque(false);
labelItem.setHorizontalAlignment(JLabel.CENTER);
labelItem.setForeground(Color.WHITE);
panel.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 2));
panel.setBackground(Color.BLUE);
panel.add(labelItem);
}
public Component getEditorComponent(){
return this.panel;
}
public Object getItem(){
return this.selectedItem;
}
public void setItem(Object item){
if(item == null){
return;
}
this.selectedItem = item;
labelItem.setText(item.toString());
}
}
EDIT
I've added a MCVE and as you can see it is the "problem" that the JComboBox is focused that has to do with my issue. I've placed a button next to the ComboBox to help with removing the focus from the ComboBox.
Simply doing a setFocusable(false) would fix it, but also take away some of the functionality of the rest of the program, so this is not desired.

for better help sooner post an SSCCE / MCVE, short, runnable, compilable, with hardcoded value for JComboBox / XxxComboBoxModel in local variable
JList has Boolean array implemented as default in API (no idea whats hidden in
String trueFalseItem = Boolean.toString(tempValue); and with value stored JComboBox model)
this is just code minimum to test isSelected and to change JList.setSelectionXxx inside DefaultListCellRenderer
for example (code in SSCCE / MCVE form)
.
.
import java.awt.Color;
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.util.Vector;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.SwingUtilities;
public class ComboBoxBooleanModel {
private javax.swing.Timer timer = null;
private Vector<Boolean> comboBoxItems;
private JComboBox box;
public ComboBoxBooleanModel() {
comboBoxItems = new Vector<Boolean>();
comboBoxItems.add(Boolean.TRUE);
comboBoxItems.add(Boolean.FALSE);
box = new JComboBox(comboBoxItems);
box.setRenderer(new DefaultListCellRenderer() {
#Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
Component c = super.getListCellRendererComponent(
list, value, index, isSelected, cellHasFocus);
if (c instanceof JLabel) {
JLabel l = (JLabel) c;
if (Boolean.TRUE.equals(value)) {
l.setBackground(Color.RED);
if (isSelected) {
list.setSelectionForeground(Color.RED);
list.setSelectionBackground(Color.BLUE);
}
} else if (Boolean.FALSE.equals(value)) {
l.setBackground(Color.BLUE);
if (isSelected) {
list.setSelectionForeground(Color.BLUE);
list.setSelectionBackground(Color.RED);
}
}
return l;
}
return c;
}
});
JFrame frame = new JFrame("");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(box);
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
box.setSelectedIndex(1);
}
});
start();
}
private void start() {
timer = new javax.swing.Timer(2250, updateCol());
timer.start();
}
public Action updateCol() {
return new AbstractAction("text load action") {
private static final long serialVersionUID = 1L;
#Override
public void actionPerformed(ActionEvent e) {
if (box.getSelectedItem() == (Boolean) false) {
box.setSelectedItem((Boolean) true);
} else {
box.setSelectedItem((Boolean) false);
}
}
};
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
ComboBoxBooleanModel comboBoxModel = new ComboBoxBooleanModel();
}
});
}
}

Here is a short demo of 2 JCombos, one of which will not change its background color when selected :
public static void main(String[] args){
JFrame frame = new JFrame("Combos BG Color test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.getContentPane().setPreferredSize(new Dimension(400, 40));
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new GridLayout(1,2));
frame.add(mainPanel);
JComboBox<String> aCombo = new JComboBox<>(new String[]{"A","B","C"});
mainPanel.add(aCombo);
JComboBox<String> bCombo = new JComboBox<>(new String[]{"1","2","3"});
Color bgColor = bCombo.getBackground();
bCombo.setRenderer(new DefaultListCellRenderer() {
#Override
public void paint(Graphics g) {
setBackground(bgColor);
super.paint(g);
}
});
mainPanel.add(bCombo);
frame.pack();
frame.setVisible(true);
}
(Most of the credit goes to this answer)

Based on this example : https://stackoverflow.com/a/17359895/3259386
I have two panels, one for drag and the other for drop, I just drag a copy and I don't move the dragged image.
the code is...
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.datatransfer.DataFlavor;
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.DropTarget;
import java.awt.dnd.DropTargetAdapter;
import java.awt.dnd.DropTargetDropEvent;
import java.io.IOException;
import java.net.URL;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.TransferHandler.TransferSupport;
import javax.swing.border.TitledBorder;
public class Test {
public static void main(String[] args) {
createAndShowJFrame();
}
public static void createAndShowJFrame() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = createJFrame();
frame.setVisible(true);
}
});
}
private static JFrame createJFrame() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setTitle("Test");
JPanel panel = createEmptyJPanel();
new MyDropTargetListener(panel);//this must be done or we wont be able to drop any image onto the empty panel
frame.add(panel, BorderLayout.CENTER);
try {
frame.add(createJLabelPanel(), BorderLayout.SOUTH);
} catch (Exception ex) {
ex.printStackTrace();
}
frame.pack();
return frame;
}
private static JPanel createEmptyJPanel() {
final JPanel p = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
};
p.setBorder(new TitledBorder("Drag Image onto this panel"));
TransferHandler dnd = new TransferHandler() {
#Override
public boolean canImport(TransferSupport support) {
if (!support.isDrop()) {
return false;
}
//only Strings
if (!support.isDataFlavorSupported(DataFlavor.imageFlavor)) {
return false;
}
return true;
}
#Override
public boolean importData(TransferSupport support) {
if (!canImport(support)) {
return false;
}
Transferable tansferable = support.getTransferable();
Icon ico;
try {
ico = (Icon) tansferable.getTransferData(DataFlavor.imageFlavor);
} catch (Exception e) {
e.printStackTrace();
return false;
}
p.add(new JLabel(ico));
return true;
}
};
p.setTransferHandler(dnd);
return p;
}
private static JPanel createJLabelPanel() throws Exception {
JPanel panel = new JPanel();
panel.setBorder(new TitledBorder("Drag Image from here to Panel above"));
JLabel label1 = new JLabel(new ImageIcon(new URL("http://i.stack.imgur.com/gJmeJ.png")));
JLabel label2 = new JLabel(new ImageIcon(new URL("http://i.stack.imgur.com/8BGfi.png")));
JLabel label3 = new JLabel(new ImageIcon(new URL("http://i.stack.imgur.com/1lgtq.png")));
MyDragGestureListener dlistener = new MyDragGestureListener();
DragSource ds1 = new DragSource();
ds1.createDefaultDragGestureRecognizer(label1, DnDConstants.ACTION_COPY, dlistener);
DragSource ds2 = new DragSource();
ds2.createDefaultDragGestureRecognizer(label2, DnDConstants.ACTION_COPY, dlistener);
DragSource ds3 = new DragSource();
ds3.createDefaultDragGestureRecognizer(label3, DnDConstants.ACTION_COPY, dlistener);
panel.add(label1);
panel.add(label2);
panel.add(label3);
return panel;
}
}
class MyDropTargetListener extends DropTargetAdapter {
private DropTarget dropTarget;
private JPanel p;
public MyDropTargetListener(JPanel panel) {
p = panel;
dropTarget = new DropTarget(panel, DnDConstants.ACTION_COPY, this, true, null);
}
#Override
public void drop(DropTargetDropEvent event) {
try {
DropTarget test = (DropTarget) event.getSource();
Component ca = (Component) test.getComponent();
Point dropPoint = ca.getMousePosition();
Transferable tr = event.getTransferable();
if (event.isDataFlavorSupported(DataFlavor.imageFlavor)) {
Icon ico = (Icon) tr.getTransferData(DataFlavor.imageFlavor);
if (ico != null) {
p.add(new JLabel(ico));
p.revalidate();
p.repaint();
event.dropComplete(true);
}
} else {
event.rejectDrop();
}
} catch (Exception e) {
e.printStackTrace();
event.rejectDrop();
}
}
}
class MyDragGestureListener implements DragGestureListener {
#Override
public void dragGestureRecognized(DragGestureEvent event) {
JLabel label = (JLabel) event.getComponent();
final Icon ico = label.getIcon();
Transferable transferable = new Transferable() {
#Override
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{DataFlavor.imageFlavor};
}
#Override
public boolean isDataFlavorSupported(DataFlavor flavor) {
if (!isDataFlavorSupported(flavor)) {
return false;
}
return true;
}
#Override
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
return ico;
}
};
event.startDrag(null, transferable);
}
}
when I drop the element on the top panel, the element is placed in the center like this
I want to drop everywhere on the top panel.
When I set the top panel to null layout like this : p.setLayout(null);, the dropped image don't show anymore.

when I drop the element on the top panel, the element is placed in the center like this
The default layout manager for the panel is a FlowLayout.
When I set the top panel to null layout ... the dropped image don't show anymore.
When you use a null layout you are responsible for setting the size and location of the component.
//p.add(new JLabel(ico));
JLabel label = new JLabel(ico);
label.setSize( label.getPreferredSize());
label.setLocation(...);
p.add(label);
You can also use the TransferSupport class to get the DropLocation class which contains the drop point that you can use the set the location of the label.

im not gonna write any code because this will be simply too annoying but you can set a mouse cursor type and make it when they click the box uptop they add a imageicon and use a actionlistener to see if there still pressing the left click button

after looking for an answer for 3 hours, I am just about to give up on this idea:
I am making an application that displays the followers of a Twitch streamer.
A couple of features i am trying to add:
the display frame is a separate window from the controls frame.
I am trying to use (JFrame as display window) (JDialog as controls frame)
And furthermore: Settings is in another JDialog (this one has Modal(true))
Settings needs to be able to send the JFrame information such as: "username" and "text color"
And the settings JDialog will only pop up from clicking "settings" on the controls JDialog.
It will setVisible(false) when you click "save settings" or the X.
On the controls JDialog (b_console) needs to receive error messages and info like that.
And on the same JDialog, "filler" needs to receive follower count and things like that.
Here follows my code involving the transfers listed above:
package javafollowernotifier;
import java.awt.*;
import java.awt.event.*;
import java.awt.Graphics.*;
import javax.swing.*;
import java.io.*;
import java.net.URL;
public class JavaFollowerNotifier extends JFrame implements ComponentListener
{
Settings settings = new Settings();
ControlPanel ctrlPnl = new ControlPanel();
public JavaFollowerNotifier()
{
try
{
settings.readSettings();
}
catch(Exception e)
{
ctrlPnl.b_console.setText("Error");
System.out.println(e);
}
}
public void grabFollower()
{
ctrlPnl.b_console.setText("Retrieving Info...");
try
{
URL twitch = new URL("https://api.twitch.tv/kraken/channels/" + savedSettings[1] + "/follows?limit=1&offset=0");
ctrlPnl.b_console.setText("Retrieved");
}
catch(Exception e)
{
ctrlPnl.b_console.setText("Error");
System.out.println(e);
}
}
public void grabStats()
{
ctrlPnl.b_console.setText("Retrieving Info...");
try
{
URL twitch = new URL("https://api.twitch.tv/kraken/channels/" + savedSettings[1] + "/follows?limit=1&offset=0");
ctrlPnl.filler.setText("Followers: " + totalFollowers + "\nLatest: " + lastFollower);
ctrlPnl.b_console.setText("Retrieved");
}
catch(Exception e)
{
ctrlPnl.b_console.setText("Error");
System.out.println(e);
}
}
public void componentMoved(ComponentEvent arg0)
{
//this is only to *attach this JDialog to the JFrame and make it move together my plan is to have it undecorated as well
int x = this.getX() + this.getWidth();
int y = this.getY();
ctrlPnl.movePanel(x, y);
}
public void paint(Graphics g)
{
if(clearPaint == false)
{
//any "savedSettings[n]" are saved in Settings.java (just not in this version)
g.setColor(Color.decode(savedSettings[3]));
scaledFont = scaleFont(follower + " followed!", bounds, g, new Font(savedSettings[2], Font.PLAIN, 200));
}
}
}
package javafollowernotifier;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Settings extends JDialog implements ActionListener
{
JavaFollowerNotifier jfollow = new JavaFollowerNotifier();
ControlPanel ctrlPnl = new ControlPanel();
//here are the settings mention above
String[] savedSettings = {"imgs/b_b.jpg","username","font","color","Nightbot"};
public Settings()
{
try
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}
catch (Exception e)
{
ctrlPnl.b_console.setText("Error");
System.out.println(e);
}
}
public void saveSettings()
{
savedSettings[4] = jfollow.lastFollower;
try
{
PrintWriter save = new PrintWriter("config.cfg");
ctrlPnl.b_console.setText("Saving...");
for(int i = 0; i < 5; i++)
{
save.println(savedSettings[i]);
}
save.close();
ctrlPnl.b_console.setText("Saved");
}
catch(Exception e)
{
ctrlPnl.b_console.setText("Error");
System.out.println(e);
canClose = false;
}
readSettings();
this.repaint();
}
public void readSettings()
{
ctrlPnl.b_console.setText("Loading...");
try
{
}
catch(Exception e)
{
ctrlPnl.b_console.setText("Error");
System.out.println(e);
}
jfollow.lastFollower = savedSettings[4];
try
{
}
catch(Exception e)
{
ctrlPnl.b_console.setText("Error");
System.out.println(e);
}
ctrlPnl.b_console.setText("Loaded Settings");
}
}
package javafollowernotifier;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ControlPanel extends JDialog implements ActionListener
{
public ControlPanel()
{
try
{
}
catch (Exception e)
{
b_console.setText("Error");
System.out.println(e);
}
}
public void movePanel(int x, int y)
{
//here is where i *attach the JDialog to the JFrame
controlPanel.setLocation(x, y);
}
public void actionPerformed(ActionEvent ie)
{
if(ie.getSource() == b_settings)
{
settings.frame.setVisible(true);
}
}
}

I tried to fix your program, but I wasn't too sure about its flow. So I created another simple one. What I did was pass the labels from the main frame to the dialogs' constructors. In the dialog, I took those labels and changed them with text entered in their text fields. If you hit enter after writing text from the dialog, you'll see the text in the frame change
public class JavaFollowerNotifier1 extends JFrame{
private JLabel controlDialogLabel = new JLabel(" ");
private JLabel settingDialogLabel = new JLabel(" ");
private ControlDialog control;
private SettingsDialog settings;
public JavaFollowerNotifier1() {
control = new ControlDialog(this, true, controlDialogLabel);
settings = new SettingsDialog(this, true, settingDialogLabel);
....
class ControlDialog extends JDialog {
private JLabel label;
public ControlDialog(final Frame frame, boolean modal, final JLabel label) {
super(frame, modal);
this.label = label;
....
class SettingsDialog extends JDialog {
private JLabel label;
public SettingsDialog(final Frame frame, boolean modal, final JLabel label) {
super(frame, modal);
this.label = label;
Test it out and let me know if you have any questions
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class JavaFollowerNotifier1 extends JFrame{
private JLabel controlDialogLabel = new JLabel(" ");
private JLabel settingDialogLabel = new JLabel(" ");
private JButton showControl = new JButton("Show Control");
private JButton showSetting = new JButton("Show Settings");
private ControlDialog control;
private SettingsDialog settings;
public JavaFollowerNotifier1() {
control = new ControlDialog(this, true, controlDialogLabel);
settings = new SettingsDialog(this, true, settingDialogLabel);
showControl.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
control.setVisible(true);
}
});
showSetting.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
settings.setVisible(true);
}
});
JPanel buttonPanel = new JPanel();
buttonPanel.add(showControl);
buttonPanel.add(showSetting);
add(buttonPanel, BorderLayout.SOUTH);
add(controlDialogLabel, BorderLayout.NORTH);
add(settingDialogLabel, BorderLayout.CENTER);
pack();
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new JavaFollowerNotifier1();
}
});
}
}
class ControlDialog extends JDialog {
private JLabel label;
private JTextField field = new JTextField(15);
private JButton button = new JButton("Close");
private String s = "";
public ControlDialog(final Frame frame, boolean modal, final JLabel label) {
super(frame, modal);
this.label = label;
setLayout(new BorderLayout());
add(field, BorderLayout.NORTH);
add(button, BorderLayout.CENTER);
pack();
setLocationRelativeTo(frame);
field.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
s = field.getText();
label.setText("Message from Control Dialog: " + s);
}
});
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
ControlDialog.this.setVisible(false);
}
});
}
}
class SettingsDialog extends JDialog {
private JLabel label;
private JTextField field = new JTextField(15);
private JButton button = new JButton("Close");
private String s = "";
public SettingsDialog(final Frame frame, boolean modal, final JLabel label) {
super(frame, modal);
this.label = label;
setLayout(new BorderLayout());
add(field, BorderLayout.NORTH);
add(button, BorderLayout.CENTER);
pack();
setLocationRelativeTo(frame);
field.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
s = field.getText();
label.setText("Message from Settings Dialog: " + s);
}
});
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
SettingsDialog.this.setVisible(false);
}
});
}
}

Typically when I build GUI's which use modal dialogs to gather user input, I build my own class, which extends the JDialog or in some cases a JFrame. In that class I expose a getter method for an object which I usually call DialgResult. This object acts as the Model for the input I gather from the user. In the class that has the button, or whatever control which triggers asking the user for the information, I create it, show it as a modal dialog, then when it is closed, I retrieve the object using that same getter.
This is a very primitive example:
package arg;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class asdfas extends JFrame {
public static void main(String[] args) {
asdfas ex = new asdfas();
ex.setVisible(true);
}
public asdfas() {
init();
}
private void init() {
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setBounds(100,100,200,200);
final JButton button = new JButton("Show modal dialog");
button.addActionListener( new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
Dialog d = new Dialog();
d.setVisible(true);
button.setText(d.getDialogResult().value);
revalidate();
repaint();
}
});
this.add(button);
}
class DialogResult {
public String value;
}
class Dialog extends JDialog {
JTextField tf = new JTextField(20);
private DialogResult result = new DialogResult();
public Dialog() {
super();
init();
}
private void init() {
this.setModal(true);
this.setSize(new Dimension(100,100));
JButton ok = new JButton("ok");
ok.addActionListener( new ActionListener () {
#Override
public void actionPerformed(ActionEvent arg0) {
result = new DialogResult();
result.value = tf.getText();
setVisible(false);
}
});
JPanel p = new JPanel();
p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
p.add(tf);
p.add(ok);
this.add(p);
}
public DialogResult getDialogResult() {
return result;
}
}
}

I have a JTable which can have rows dynamically added by the user. It sits in a JScrollPane, so as the number of rows gets large enough, the scroller becomes active. My desire is that when the user adds a new row, the scroller moves all the way to the bottom, so that the new row is visible in the scrollpane. I'm currently (SSCCE below) trying to use a table model listener to detect when the row is inserted, and force the scrollbar all the way down when the detection is made. However, it seems this detection is "too early," as the model has updated but the new row has not actually been painted yet, so what happens is the scroller moves all the way to the bottom just before the new row is inserted, and then the new row is inserted just below the end of the pane (out of visibility).
Obviously this approach is wrong somehow. What is the correct approach?
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.DefaultTableModel;
public class TableListenerTest {
private JFrame frame;
private JScrollPane scrollPane;
private JTable table;
private DefaultTableModel tableModel;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
TableListenerTest window = new TableListenerTest();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public TableListenerTest() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 200);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
JSplitPane splitPane = new JSplitPane();
frame.getContentPane().add(splitPane);
scrollPane = new JScrollPane();
scrollPane.setPreferredSize(new Dimension(100, 2));
splitPane.setLeftComponent(scrollPane);
tableModel = new DefaultTableModel(new Object[]{"Stuff"},0);
table = new JTable(tableModel);
scrollPane.setViewportView(table);
table.getModel().addTableModelListener(new TableModelListener() {
public void tableChanged(TableModelEvent e) {
if (e.getType() == TableModelEvent.INSERT) {
JScrollBar scrollBar = scrollPane.getVerticalScrollBar();
scrollBar.setValue(scrollBar.getMaximum());
}
}
});
JButton btnAddRow = new JButton("Add Row");
btnAddRow.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
tableModel.addRow(new Object[]{"new row"});
}
});
splitPane.setRightComponent(btnAddRow);
}
}
EDIT: Updated SSCCE below based on trashgod's request. This version still does not work, however, if I move the scrolling logic from the table model listener to the button listener as he did, then it does work!
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.DefaultTableModel;
public class TableListenerTest {
private JFrame frame;
private JScrollPane scrollPane;
private JTable table;
private DefaultTableModel tableModel;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
TableListenerTest window = new TableListenerTest();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public TableListenerTest() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 200);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
JSplitPane splitPane = new JSplitPane();
frame.getContentPane().add(splitPane);
scrollPane = new JScrollPane();
scrollPane.setPreferredSize(new Dimension(100, 2));
splitPane.setLeftComponent(scrollPane);
tableModel = new DefaultTableModel(new Object[]{"Stuff"},0);
table = new JTable(tableModel);
scrollPane.setViewportView(table);
table.getModel().addTableModelListener(new TableModelListener() {
public void tableChanged(TableModelEvent e) {
if (e.getType() == TableModelEvent.INSERT) {
int last = table.getModel().getRowCount() - 1;
Rectangle r = table.getCellRect(last, 0, true);
table.scrollRectToVisible(r);
}
}
});
JButton btnAddRow = new JButton("Add Row");
btnAddRow.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
tableModel.addRow(new Object[]{"new row"});
}
});
splitPane.setRightComponent(btnAddRow);
}
}

This example uses scrollRectToVisible() to (conditionally) scroll to the last cell rectangle. As a feature you can click on the thumb to suspend scrolling and release to resume.
private void scrollToLast() {
if (isAutoScroll) {
int last = table.getModel().getRowCount() - 1;
Rectangle r = table.getCellRect(last, 0, true);
table.scrollRectToVisible(r);
}
}
Addendum: I tried scrollRectToVisible in my SSCCE, and it still exhibits the same problem.
This Action provides both mouse and keyboard control:
JButton btnAddRow = new JButton(new AbstractAction("Add Row") {
#Override
public void actionPerformed(ActionEvent e) {
tableModel.addRow(new Object[]{"new row"});
int last = table.getModel().getRowCount() - 1;
Rectangle r = table.getCellRect(last, 0, true);
table.scrollRectToVisible(r);
}
});
Addendum: Here's a variation on your example that illustrates a revised layout strategy.
/** #see https://stackoverflow.com/a/14429388/230513 */
public class TableListenerTest {
private static final int N = 8;
private JFrame frame;
private JScrollPane scrollPane;
private JTable table;
private DefaultTableModel tableModel;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
TableListenerTest window = new TableListenerTest();
window.frame.setVisible(true);
}
});
}
public TableListenerTest() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.X_AXIS));
tableModel = new DefaultTableModel(new Object[]{"Stuff"}, 0);
for (int i = 0; i < N; i++) {
tableModel.addRow(new Object[]{"new row"});
}
table = new JTable(tableModel) {
#Override
public Dimension getPreferredScrollableViewportSize() {
return new Dimension(200, table.getRowHeight() * N);
}
};
scrollPane = new JScrollPane();
scrollPane.setViewportView(table);
JButton btnAddRow = new JButton(new AbstractAction("Add Row") {
#Override
public void actionPerformed(ActionEvent e) {
tableModel.addRow(new Object[]{"new row"});
int last = table.getModel().getRowCount() - 1;
Rectangle r = table.getCellRect(last, 0, true);
table.scrollRectToVisible(r);
}
});
frame.add(scrollPane);
frame.add(btnAddRow);
frame.pack();
}
}

However, it seems this detection is "too early,"
For emphasis (#trashgod already mentioned it in a comment): that's true - and expected and a fairly general issue in Swing :-)
The table - and any other view with any model, not only data but also selection, adjustment, ... - is listening to the model to update itself. So a custom listener is just yet another listener in the line (with serving sequence undefined). If it wants to do something that depends on the view state it has to make sure to do so after all internal update is ready (in this concrete context, the internal update includes the update of the adjustmentModel of the vertical scrollBar) Postponing the custom processing until the internals are done, is achieved by wrapping SwingUtilities.invokeLater:
TableModelListener l = new TableModelListener() {
#Override
public void tableChanged(TableModelEvent e) {
if (e.getType() == TableModelEvent.INSERT) {
invokeScroll();
}
}
protected void invokeScroll() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
int last = table.getModel().getRowCount() - 1;
Rectangle r = table.getCellRect(last, 0, true);
table.scrollRectToVisible(r);
}
});
}
};
table.getModel().addTableModelListener(l);