I'm getting a NullPointerException in my JList, but the source of the exception seems to be the Swing event handling code. The JList has a key listener which will delete the selected item when the Delete key is pressed. The exception is only thrown on the second and all subsequent deletions from the list. Any ideas on how to fix it?
Sample code to reproduce the problem and the exception that is produced are included below:
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Vector;
import javax.swing.JFrame;
import javax.swing.JList;
public class Sample {
public static void main(String[] args) {
final JFrame frame = new JFrame();
final Vector<String> list = new Vector<String>();
for (int i = 0; i < 5; ++i) {
list.add("String " + i);
}
final JList listView = new JList(list);
listView.addKeyListener(new KeyListener() {
#Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_DELETE) {
list.remove(listView.getSelectedIndex());
listView.updateUI();
}
}
#Override
public void keyReleased(KeyEvent e) { }
#Override
public void keyTyped(KeyEvent e) { }
});
frame.add(listView);
frame.pack();
frame.setVisible(true);
}
}
Here's the exception being thrown:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.plaf.basic.BasicListUI$Handler.isNavigationKey(Unknown Source)
at javax.swing.plaf.basic.BasicListUI$Handler.keyPressed(Unknown Source)
at java.awt.AWTEventMulticaster.keyPressed(Unknown Source)
at java.awt.Component.processKeyEvent(Unknown Source)
at javax.swing.JComponent.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
The problem is in this line:
listView.updateUI();
Calling this method causes the current UI to be uninstalled from the JList, yet it is still being used to process events. This results in the NullPointerException you see. This isn't the method you want to call.
Try
listView.revalidate();
instead to cause the component to re-layout or perhaps just repaint() to get it to repaint.
list.registerKeyboardAction(this,
KeyStroke.getKeyStroke(KeyEvent.VK_DELETE, 0), JComponent.WHEN_FOCUSED);
EDIT: remove unrelated code
Instead of the updateUI() you should call the revalidate() and repaint() method. And probably a check if the element in the list really exists wouldn't be a bad idea.
#Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_A) {
if(list.get(listView.getSelectedIndex()) != null) {
list.remove(listView.getSelectedIndex());
listView.revalidate();
listView.repaint();
}
}
}
Related
I have a java application where when the user presses a button, I want it to open another different application in a new window. However, the application is a programmed one in Eclipse, not one downloaded onto my computer. I have tried various things such as running threads, but to no avail. Here is the section of the class where the user pushes the button:
JButton LiveFeed = new JButton("Live Feed");
final JPanel jsr3 = new JPanel();
jsr3.add(LiveFeed);
LiveFeed.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
new KinectViewer();
}
});
jsr3.setVisible(true);
And here is the class that I am trying to open seperate from the main application:
package skeleton;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import edu.ufl.digitalworlds.gui.DWApp;
#SuppressWarnings("serial")
public class KinectViewer extends DWApp implements ChangeListener
{
Kinect myKinect;
ViewerPanel3D main_panel;
JSlider elevation_angle;
JCheckBox near_mode;
JCheckBox seated_skeleton;
JCheckBox track_skeleton;
JButton turn_off;
JComboBox depth_resolution;
JComboBox video_resolution;
JCheckBox show_video;
JCheckBox mask_players;
JLabel accelerometer;
public void GUIsetup(JPanel p_root) {
setLoadingProgress("Intitializing Kinect...",20);
myKinect=new Kinect();
if(myKinect.start(true,Kinect.NUI_IMAGE_RESOLUTION_320x240,Kinect.NUI_IMAGE_RESOLUTION_640x480)==0)
{
DWApp.showErrorDialog("ERROR", "<html><center><br>ERROR: The Kinect device could not be initialized.<br><br>1. Check if the Microsoft's Kinect SDK was succesfully installed on this computer.<br> 2. Check if the Kinect is plugged into a power outlet.<br>3. Check if the Kinect is connected to a USB port of this computer.</center>");
//System.exit(0);
}
myKinect.computeUV(true);
near_mode=new JCheckBox("Near mode");
near_mode.addActionListener(this);
seated_skeleton=new JCheckBox("Seated skeleton");
seated_skeleton.addActionListener(this);
elevation_angle=new JSlider();
elevation_angle.setMinimum(-27);
elevation_angle.setMaximum(27);
elevation_angle.setValue((int)myKinect.getElevationAngle());
elevation_angle.setToolTipText("Elevation Angle ("+elevation_angle.getValue()+" degrees)");
elevation_angle.addChangeListener(this);
turn_off=new JButton("Turn off");
turn_off.addActionListener(this);
depth_resolution=new JComboBox();
depth_resolution.addItem("80x60");
depth_resolution.addItem("320x240");
depth_resolution.addItem("640x480");
depth_resolution.setSelectedIndex(1);
depth_resolution.addActionListener(this);
video_resolution=new JComboBox();
video_resolution.addItem("640x480");
video_resolution.addItem("1280x960");
video_resolution.setSelectedIndex(0);
video_resolution.addActionListener(this);
track_skeleton=new JCheckBox("Track Skeletons");
track_skeleton.setSelected(true);
track_skeleton.addActionListener(this);
show_video=new JCheckBox("Show video");
show_video.setSelected(true);
show_video.addActionListener(this);
mask_players=new JCheckBox("Mask Players");
mask_players.setSelected(false);
mask_players.addActionListener(this);
JPanel controls=new JPanel(new GridLayout(0,6));
controls.add(new JLabel("Depth Stream:"));
controls.add(depth_resolution);
controls.add(near_mode);
controls.add(new JLabel("Video Stream:"));
controls.add(video_resolution);
controls.add(show_video);
controls.add(new JLabel("Skeleton Stream:"));
controls.add(track_skeleton);
controls.add(seated_skeleton);
controls.add(mask_players);
accelerometer=new JLabel("0,0,0");
controls.add(accelerometer);
controls.add(elevation_angle);
//controls.add(turn_off);
setLoadingProgress("Intitializing OpenGL...",60);
main_panel=new ViewerPanel3D();
myKinect.setViewer(main_panel);
myKinect.setLabel(accelerometer);
p_root.add(main_panel, BorderLayout.CENTER);
p_root.add(controls, BorderLayout.SOUTH);
System.out.print("GUIsetup");
}
public void GUIclosing()
{
myKinect.stop();
}
private void resetKinect()
{
if(turn_off.getText().compareTo("Turn on")==0) return;
myKinect.stop();
int depth_res=Kinect.NUI_IMAGE_RESOLUTION_INVALID;
if(depth_resolution.getSelectedIndex()==0) depth_res=Kinect.NUI_IMAGE_RESOLUTION_80x60;
else if(depth_resolution.getSelectedIndex()==1) depth_res=Kinect.NUI_IMAGE_RESOLUTION_320x240;
else if(depth_resolution.getSelectedIndex()==2) depth_res=Kinect.NUI_IMAGE_RESOLUTION_640x480;
int video_res=Kinect.NUI_IMAGE_RESOLUTION_INVALID;
if(video_resolution.getSelectedIndex()==0) video_res=Kinect.NUI_IMAGE_RESOLUTION_640x480;
else if(video_resolution.getSelectedIndex()==1) video_res=Kinect.NUI_IMAGE_RESOLUTION_1280x960;
myKinect.start(track_skeleton.isSelected(),depth_res,video_res);
myKinect.computeUV(true);
if(seated_skeleton.isSelected())myKinect.startSkeletonTracking(true);
if(near_mode.isSelected()) myKinect.setNearMode(true);
}
public static void main(String args[]) {
createMainFrame("Kinect Viewer App");
app=new KinectViewer();
setFrameSize(730,570,null);
System.out.print("main");
}
#Override
public void GUIactionPerformed(ActionEvent e)
{
if(e.getSource()==near_mode)
{
if(near_mode.isSelected()) myKinect.setNearMode(true);
else myKinect.setNearMode(false);
}
else if(e.getSource()==seated_skeleton)
{
if(seated_skeleton.isSelected()) myKinect.startSkeletonTracking(true);
else myKinect.startSkeletonTracking(false);
}
else if(e.getSource()==track_skeleton)
{
if(track_skeleton.isSelected())
{
if(seated_skeleton.isSelected()) myKinect.startSkeletonTracking(true);
else myKinect.startSkeletonTracking(false);
}
else myKinect.stopSkeletonTracking();
}
else if(e.getSource()==turn_off)
{
if(turn_off.getText().compareTo("Turn off")==0)
{
myKinect.stop();
turn_off.setText("Turn on");
}
else
{
turn_off.setText("Turn off");
resetKinect();
}
}
else if(e.getSource()==depth_resolution)
{
resetKinect();
}
else if(e.getSource()==video_resolution)
{
resetKinect();
}
else if(e.getSource()==show_video)
{
main_panel.setShowVideo(show_video.isSelected());
}
else if(e.getSource()==mask_players)
{
myKinect.maskPlayers(mask_players.isSelected());
}
}
#Override
public void stateChanged(ChangeEvent e) {
if(e.getSource()==elevation_angle)
{
if(!elevation_angle.getValueIsAdjusting())
{
myKinect.setElevationAngle(elevation_angle.getValue());
elevation_angle.setToolTipText("Elevation Angle ("+elevation_angle.getValue()+" degrees)");
}
}
}
}
However, when I run this, I get this following NPE:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at edu.ufl.digitalworlds.gui.DWApp.<init>(DWApp.java:173)
at skeleton.KinectViewer.<init>(KinectViewer.java:53)
at skeleton.TestSplitPanels$1.actionPerformed(TestSplitPanels.java:66)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Why is this?
Please note that KinectViewer can be opened as its own java application and works just fine by itself and if you are wondering about the DWApp, the DWApp class is a class in the edu.ufl.digitalworlds.gui package in the ufdw.jar (downloaded via this site posted above). It has two types of its class: one for a java application (which I'm using) and one for an applet. Inside the class are a bunch of methods seeming to deal with application look and processes (word sizing, formating, error dialogs, ect.). During setting everything up, I imported a project from git, and used a uri of "research.dwi.ufl.edu/j4kdemo".
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.PrintWriter;
import java.sql.*;
import java.net.*;
public class connection {
JTextField textfeild;
JButton button;
String text;
Socket sock;
PrintWriter writer;
JButton button1;
public static void main(String[] args) {
connection user1 = new connection();
user1.go();
}//main method close
public void go() {
JFrame frame12 = new JFrame();
JPanel centerpanel12 = new JPanel();
centerpanel12.setLayout(new BoxLayout(centerpanel12, BoxLayout.Y_AXIS));
textfeild = new JTextField(20);
centerpanel12.add(textfeild);
//textfeild.addActionListener(new textfeildlitner());
frame12.add(centerpanel12);
button = new JButton("Click Me");
centerpanel12.add(button);
button.addActionListener(new buttonlitner());
button1 = new JButton("DataDisplay");
centerpanel12.add(button1);
button1.addActionListener(new buttonlitner1());
frame12.getContentPane().add(BorderLayout.CENTER, centerpanel12);
frame12.pack();
frame12.setVisible(true);
frame12.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}//go method close
/*class textfeildlitner implements ActionListener{
public void actionPerformed(ActionEvent ev){
}
}//inner class textfeildlitner close*/
class buttonlitner implements ActionListener {
public void actionPerformed(ActionEvent ev) {
button.setText("I AM Clicked");
String name = textfeild.getText();
System.out.println(name);
textfeild.setText("");
textfeild.requestFocus();
}//method close
}//inner class close
class buttonlitner1 implements ActionListener {
void connection() {
try {
String user = "SQlUI";
String pass = "123456";
String db = "jdbc:sqlserver://localhost:1234;" + ";databaseName=SQlUI";
Class.forName("com.microsoft.sqlserver.jdbc");
Connection con = DriverManager.getConnection(db, user, pass);
Statement s1 = con.createStatement();
ResultSet r1 = s1.executeQuery("select * from Table_1");
String[] result = new String[20];
if (r1 != null) {
while (r1.next()) {
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result.length; j++) {
result[j] = r1.getString(i);
System.out.println(result[j]);
}//for j
}//for i
}//if
}//try
} catch (Exception ex) {
ex.printStackTrace();
}//catch
}//connection()
public void actionPerformed(ActionEvent ev) {
button1.setText("Processing");
new buttonlitner1().connection();
}//method close
}//inner class close
}// outer class close
While running this code i am getting following exception----
java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at connection$buttonlitner1.connection(connection.java:66)
at connection$buttonlitner1.actionPerformed(connection.java:89)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Don't know why its happening. I have added the sqlserver.jar in eclipse external library.
The connection name
String db="jdbc:sqlserver://localhost:1234;"+";databaseName=SQlUI";
is correct. i am attaching the screenshot of the sqlserver.jar which i have added to external library.
The driver class is com.microsoft.sqlserver.jdbc.SQLServerDriver and not com.microsoft.sqlserver.jdbc. Try to use:
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
It is an application that, among other things, a list of personalities. Once launched, the data of a personality are displayed on the left side, there are two lists: one comprising all categories of personalities and another incorporating all the names in this list.The user select a row in each JList, he clicks on the button "search" ... The code then makes a call to findByCriteria .... But here, I have a NullPointerException ... After some research, I realized that this is because my lists are poorly or not initialized ... I look at my code but I do not understand how it is because the call to the methods that must be initialized before the call is to listener on my Button ... The strangest thing is that when I run the application, the lists are filled. I used the MVC pattern with the method update...
Here is the code from my view:
modelListCat = new DefaultListModel();
listCategories = new JList();
listCategories.setName("category");
scrollPaneCat.setViewportView(listCategories);
listCategories.setPreferredSize(new Dimension(0, 90));
listCategories.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
listCategories.setLayoutOrientation(JList.HORIZONTAL_WRAP);
listCategories.setVisibleRowCount(-1);
PersonalitiesController.getInstance().setJListForCategories(personalitiesListCat, listCategories, modelListCat);
and a little further:
modelListNames = new DefaultListModel();
listNames = new JList();
listNames.setName("name");
scrollPaneN.setViewportView(listNames);
listNames.setPreferredSize(new Dimension(0, 110));
listNames.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
listNames.setSelectedIndex(0);
listNames.setLayoutOrientation(JList.HORIZONTAL_WRAP);
listNames.setVisibleRowCount(-1);
PersonalitiesController.getInstance().setJListForNames(personalitiesListNames, listNames, modelListNames);
btnSearch = new JButton("Rechercher");
btnSearch.setActionCommand("search");
btnSearch.setName("search");
GridBagConstraints gbc_btnSearch = new GridBagConstraints();
gbc_btnSearch.insets = new Insets(0, 0, 5, 5);
gbc_btnSearch.gridx = 0;
gbc_btnSearch.gridy = 4;
westPanel.add(btnSearch, gbc_btnSearch);
this.btnSearch.addActionListener(PersonalitiesController.getInstance());
The method code to initialize the JList class (this is the same for the JList names) in PersonalitiesController:
public void setJListForCategories(List<TPersonalities> personalitiesListCat, JList listCategories, DefaultListModel modelListCat){
modelListCat = new DefaultListModel();
modelListCat.addElement("Toute");
for(int i = 0; i < personalitiesListCat.size(); i++){
modelListCat.addElement(personalitiesListCat.get(i));
}
listCategories.setModel(modelListCat);
setListNames(listCategories);
}
Here is the code of ActionPerformed in PersonalitiesController:
public void actionPerformed(ActionEvent ev) {
// TODO Auto-generated method stub
//JButton button = (JButton)ev.getSource();
if("search".equals(ev.getActionCommand())){
DefaultListModel modelListCat = (DefaultListModel)listCategories.getModel();
DefaultListModel modelListNames = (DefaultListModel)listNames.getModel();
int selected = this.listCategories.getSelectedIndex( );
if(selected != -1){
for(int i = 0; i != listCategories.getSelectedIndex(); i++){
this.category = (String)modelListCat.getElementAt(selected);
}
}
int selected2 = this.listNames.getSelectedIndex( );
if(selected2 != -1){
for(int j =0; j != listNames.getSelectedIndex(); j++){
this.name = (String)modelListNames.getElementAt(selected2);
}
}
if(category.equalsIgnoreCase("Toute") && category == ""){
if(!name.equalsIgnoreCase("Tout") && name != ""){
model.findPersonalitiesByCriteria(name, null, null);
}
}else{
if(!name.equalsIgnoreCase("Tout") && name != ""){
model.findPersonalitiesByCriteria(name, category, null);
}else{
model.findPersonalitiesByCriteria(null, category, null);
}
}
}
}
And here is the error message:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at com.cultureAtBrussels.controller.PersonalitiesController.actionPerformed(PersonalitiesController.java:54)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
the ligne 54 is:
DefaultListModel modelListCat = (DefaultListModel)listCategories.getModel();
I have been trying after clicking a button to set the selection path in a JTree. The code sets the path correctly, but each time I click it I get a
Exception in thread "AWT-EventQueue-0" java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
at java.util.AbstractList$Itr.next(Unknown Source)
at com.treeview.main.iui.SelectableTree.actionPerformed(SelectableTree.java:225)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
And I have no idea what causes it. I read that it happens when you multiple threads try to access the same resource but I can't see the problem.
Here is the code I'm trying to run:
/**
* Handles the event when a button is clicked.
*/
#Override
public void actionPerformed(ActionEvent arg0) {
// If button "Force adaptation is clicked"
if (arg0.getSource() == forceAdapt) {
// ModelContainer.getInstance().getAdaptedTree().removeAllChildren();
// tree.setModel(new DefaultTreeModel(ModelContainer.getInstance()
// .getAdaptedTree()));
// treeModel.reload();
} else if (arg0.getSource() == showAll) {
expandFullTree(tree, ModelContainer.getInstance().getAdaptedTree());
// If button "Show All" is clicked
// tree.setModel(new DefaultTreeModel(ModelContainer.getInstance()
// .getFullTree()));
// treeModel.reload();
}
// In case recommendation button was clicked.
for (JButton button : recommendButtons) {
if (arg0.getSource() == button) {
TreeHandler th = new TreeHandler();
TreeItem node = th.getNodeByName(ModelContainer.getInstance()
.getAdaptedTree(), button.getText());
tree.setSelectionPath(new TreePath(node.getPath()));
}
}
}
Those two methods populate the ArrayList with buttons:
/**
* Handles tree selection event.
*/
public void valueChanged(TreeSelectionEvent event) {
selectedNode = (TreeItem) tree.getLastSelectedPathComponent();
// If there's predecessors.
if (!lastSelectedNode.getId().equals("-1")) {
// Display selection in bottom bar.
currentSelectionField.setText("Current Selection: "
+ selectedNode.toString() + " Prev Node : "
+ lastSelectedNode.toString());
/*
* Increase the clicks in the transition matrix and updates the
* probability transition matrix.
*/
ModelContainer.getInstance().increaseClicksOnElement(
Integer.parseInt(selectedNode.getId()) - 1,
Integer.parseInt(lastSelectedNode.getId()) - 1);
// Recalculate the Markovian matrix.
ModelContainer.getInstance().recalculateMarkovian();
// Display recommendations
displayRecommendations(ModelContainer.getInstance()
.getNextMarkovians(
(Integer.parseInt(selectedNode.getId()) - 1) + "",
5));
}
lastSelectedNode = selectedNode;
}
public void displayRecommendations(ArrayList<TreeItem> recommend) {
recommendation.removeAll();
int place = 2;
for (TreeItem treeItem : recommend) {
JButton aButton = new JButton(treeItem.toString());
aButton.setPreferredSize(new Dimension(recommendation.getWidth(),
recommendation.getHeight() / place));
aButton.addActionListener(this);
recommendButtons.add(aButton);
recommendation.add(aButton);
System.out.println(aButton.getText());
place = place * 2;
}
recommendation.revalidate();
recommendation.repaint();
}
I am making a small hobby game, I have a couple of classes so far. There are two classes that I am having some issues with, the classes in question are listed below.
Screen.Java
package geisst.flat;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class Screen extends JFrame {
public int x = 100;
public int y = 100;
public Screen() {
this.setSize(400, 400);
this.setTitle("Flat Game");
this.setResizable(false);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
addKeyListener(new KeyListen());
}
public void paint(Graphics g) {
BufferedImage mainImage = null;
try {
mainImage = ImageIO.read(new File("res/test.gif"));
} catch(IOException e) {
}
g.drawImage(mainImage, x, y, null);
repaint();
}
}
And KeyListen.Java
package geisst.flat;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
public class KeyListen extends KeyAdapter {
Screen screen;
#Override
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
if(keyCode == KeyEvent.VK_LEFT) {
screen.x += 3;
}
}
}
KeyListen is supposed to move the mainImage's x position up by 3 pixels, but I recieve the following error.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at geisst.flat.KeyListen.keyPressed(KeyListen.java:15)
at java.awt.Component.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Window.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Do you guy's and gal's have any idea why this would be happening? It's probably something really obvious :P
Thanks in advance,
GeissT
You are never initializing the value of screen.
What you can do is something like this:
In the KeyListener Class
public KeyListen (Screen screen) {
this.screen = screen;
}
and in the Screen Class:
addKeyListener(new KeyListen(this));
You never initialize screen, so it is null, and yet you use it's properties:
screen.x += 3;
You should pass a reference to the Screen object to the listener, or by calling getSource:
#Override
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
if(keyCode == KeyEvent.VK_LEFT) {
if (e.getSource() instanceof Screen)
((Screen)e.getSource()).x += 3;
}
}
1) not good idea paint directly to the JFrame, put there JPanel, JComponent or JLabel
2) for Swing JComponents is there paintComponent instead of paint, paint is correct method for painting to the RootPane or GlassPane (derived Component from JFrame)
3) use KeyBindings rather than KeyListener, because KeyListener doesn't works without Focus in the Window, not good idea to setFocusable to the ContentPane
4) use JComponent for Custom Painting or JLabel with Icon
5) example for KeyBindings here