F
freesoft_2000
Hi everyone,
I am trying to save the contents the of the jtable
together with all its fonts and everything else. The program compiles
without any errors but When i try to save the contents of the JTable an
exception is thrown in the tablesaveas method in the below method
Please note that i am saving the jtable as an object. I am providing the
below runnable example so you guys can compile and run and see what i
mean.
Here is the code
This is the exception that is thrown. The exception does not seem to be
thrown from my own code.
Here is the exception thrown
As you can see from my above code in the tablesaveas method i am saving
six objects but if i change the tablesaveas method to this(see the below
code) the table is saved without any problems
The only difference as you can see is that i am writing two objects
instead of six and i don't really know what's wrong . I don't know if this
is a bug in Java or am i missing something.
I am using JDK 1.4.2_04
I hope someone can help me with this problem
Any help is greatly appreciated
Thank You
Yours Sincerely
Richard West
I am trying to save the contents the of the jtable
together with all its fonts and everything else. The program compiles
without any errors but When i try to save the contents of the JTable an
exception is thrown in the tablesaveas method in the below method
Please note that i am saving the jtable as an object. I am providing the
below runnable example so you guys can compile and run and see what i
mean.
Here is the code
Code:
import java.awt.*;
import java.io.*;
import java.util.*;
import java.awt.print.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
public class JTablesui implements ActionListener, ItemListener
{
JFrame fr = new JFrame ("Frame");
JDialog Dialog1 = new JDialog (fr, "Row Height");
JLabel Label1 = new JLabel("Label1 ",
SwingConstants.RIGHT);
JLabel Label2 = new JLabel(" ",
SwingConstants.LEFT);
JLabel Label3 = new JLabel("Enter table row height in pixels");
JButton Button6 = new JButton("Save As");
JButton Button19 = new JButton("Set Row Height");
JButton Button20 = new JButton("Set Height");
JButton Button21 = new JButton("Close");
JButton Button22 = new JButton("Foreground Color For Cells");
JTextField TextField1 = new JTextField("", 10);
JTextField TextField2 = new JTextField("", 20);
JTextField TextField3 = new JTextField("", 10);
JComboBox ComboBox1;
JComboBox ComboBox2 = new JComboBox();
//The below command line sets the model for the JTable which
//has two arguments as explained below
//The first argument specifies the number of rows for the JTable to
display upon
//it's initialization
//The second argument specifies the number of columns for the JTable to
display upon
//it's initialization
DefaultTableModel TableModel1 = new DefaultTableModel(5, 10);
//The below command line sets the table model to the JTable
JTable Table1 = new JTable(TableModel1);
JScrollPane ScrollPane1 = new JScrollPane(Table1,
ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
JFileChooser FileChooser1 = new JFileChooser();
JColorChooser ColorChooser3 = new JColorChooser();
Color Color3;
Dimension Size1 = new Dimension();
int FontSize = 12;
String FontFamily = "Arial";
String SF = "";
public void initialize ()
{
Container pane = fr.getContentPane();
pane.setLayout(new FlowLayout());
fr.setSize(250,300);
fr.setLocation(300,300);
fr.setBackground(Color.lightGray);
//The below command line must be set to false so that user
//resizing is allowed
Table1.setAutoCreateColumnsFromModel(false);
Size1.width = 350;
Size1.height = 250;
ScrollPane1.setPreferredSize(Size1);
Table1.setModel(TableModel1);
//The below command line must be set to JTable.AUTO_RESIZE_OFF so that
user
//resizing is allowed
Table1.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
pane.add(ScrollPane1);
pane.add(Button6);
pane.add(Button19);
pane.add(Button22);
combofontfamilyinitialize();
pane.add(ComboBox1);
combofontsizeinitialize();
pane.add(ComboBox2);
pane.add(Label1);
// Use the JAVA constant JFrame.HIDE_ON_CLOSE for subsequent forms in
multi form
// applications
fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Button6.addActionListener(this);
Button19.addActionListener(this);
Button22.addActionListener(this);
ComboBox1.addItemListener(this);
ComboBox2.addItemListener(this);
fr.pack();
fr.setVisible(true);
}
public void combofontfamilyinitialize ()
{
//This function fills the combo box with the system available font
families
GraphicsEnvironment ge1 =
GraphicsEnvironment.getLocalGraphicsEnvironment();
String[] k = ge1.getAvailableFontFamilyNames();
ComboBox1= new JComboBox(k);
}
public void combofontsizeinitialize ()
{
//This function fills the combo box with font sizes
ComboBox2.addItem("8");
ComboBox2.addItem("9");
ComboBox2.addItem("10");
ComboBox2.addItem("11");
ComboBox2.addItem("12");
ComboBox2.addItem("14");
ComboBox2.addItem("16");
ComboBox2.addItem("18");
ComboBox2.addItem("20");
ComboBox2.addItem("22");
ComboBox2.addItem("24");
ComboBox2.addItem("26");
ComboBox2.addItem("28");
ComboBox2.addItem("36");
ComboBox2.addItem("48");
ComboBox2.addItem("72");
}
public void initializedialog1 ()
{
Container pane1 = Dialog1.getContentPane();
pane1.setLayout(new BoxLayout(pane1, BoxLayout.Y_AXIS));
Dialog1.setSize(250,300);
Dialog1.setLocation(300,300);
Dialog1.setBackground(Color.lightGray);
pane1.add(Label3);
pane1.add(TextField3);
pane1.add(Button20);
pane1.add(Button21);
//Use the JAVA constant JDialog.HIDE_ON_CLOSE for subsequent forms in
multi form
//applications
Dialog1.setDefaultCloseOperation(JDialog.HIDE_ON_CLOSE);
Button20.addActionListener(this);
Button21.addActionListener(this);
Dialog1.pack();
Dialog1.setVisible(true);
}
public void tablesaveas ()
{
//This function saves the model of the table to disk using the user
//specified file name
//This is the function in which the exception is thrown
if(FileChooser1.showSaveDialog(fr) != JFileChooser.APPROVE_OPTION)
{
return;
}
try
{
File f = FileChooser1.getSelectedFile();
SF = (f.toString() + ".DAT");
FileOutputStream fStream = new FileOutputStream(SF);
ObjectOutput stream = new ObjectOutputStream(fStream);
//The below two command lines saves the table model and table column
data
//as an object using the user specified file name
stream.writeObject(Table1.getModel());
stream.writeObject(Table1.getColumnModel());
stream.writeObject(Table1.getFont());
stream.writeObject(Table1.getForeground());
stream.writeObject(TextField3.getText());
stream.writeObject(Label2);
stream.flush();
stream.close();
fStream.close();
}
catch (Exception e)
{
Label1.setText("A table saving error has occurred");
}
}
public void actionPerformed(ActionEvent event)
{
JComponent b = (JComponent)event.getSource();
int d, d1;
String str3;
if(b == Button6)
{
//This is the function in which the exception is thrown
tablesaveas();
}
else if(b == Button19)
{
d = Table1.getRowHeight();
str3 = Integer.toString(d);
TextField3.setText(str3);
initializedialog1();
}
else if(b == Button20)
{
str3 = TextField3.getText();
d = Integer.parseInt(str3);
Table1.setRowHeight(d);
}
else if(b == Button21)
{
Dialog1.setVisible(false);
}
else if(b == Button22)
{
Color3 = ColorChooser3.showDialog(fr, "Color Chooser", Color.black);
//The below command line test to see if the Ok button or the Cancel
button
//was clicked on the JColorChooser as if no color is selected the
JColorChooser
//simply returns a null
if(Color3 != null)
{
Table1.editCellAt(0,0);
TextField1 = (JTextField)Table1.getEditorComponent();
if(TextField1 != null)
{
TextField1.setForeground(Color3);
}
Table1.setSelectionForeground(Color3);
Table1.setForeground(Color3);
}
}
}
public void itemStateChanged(ItemEvent event)
{
JComponent c = (JComponent)event.getSource();
if(c == ComboBox1)
{
Table1.editCellAt(0,0);
FontFamily = (String)ComboBox1.getSelectedItem();
Font Font1 = new Font(FontFamily, Font.PLAIN, FontSize);
TextField1 = (JTextField)Table1.getEditorComponent();
if(TextField1 != null)
{
TextField1.setFont(Font1);
}
Table1.setFont(Font1);
}
else if(c == ComboBox2)
{
String h = (String)ComboBox2.getSelectedItem();
FontSize = Integer.parseInt(h);
Table1.editCellAt(0,0);
Font Font2 = new Font(FontFamily, Font.PLAIN, FontSize);
TextField1 = (JTextField)Table1.getEditorComponent();
if(TextField1 != null)
{
TextField1.setFont(Font2);
}
Table1.setFont(Font2);
}
}
public static void main(String args[])
{
JTablesui a = new JTablesui();
a.initialize();
}
}
This is the exception that is thrown. The exception does not seem to be
thrown from my own code.
Here is the exception thrown
Code:
java.lang.NullPointerException
at
javax.swing.plaf.basic.BasicTableUI.getPreferredSize(BasicTableUI.java:908)
at javax.swing.JComponent.getPreferredSize(JComponent.java:1275)
at
javax.swing.ScrollPaneLayout.layoutContainer(ScrollPaneLayout.java:769)
at java.awt.Container.layout(Container.java:1020)
at java.awt.Container.doLayout(Container.java:1010)
at java.awt.Container.validateTree(Cojava.lang.NullPointerException
at javax.swing.plaf.basic.BasicTableUI.paint(BasicTableUI.java:939)
at javax.swing.plaf.ComponentUI.update(ComponentUI.java:142)
at javax.swing.JComponent.paintComponent(JComponent.java:541)
at javax.swing.JComponent.paint(JComponent.java:808)
at javax.swing.JComponent.paintChildren(JComponent.java:647)
at javax.swing.JComponent.paint(JComponent.java:817)
at javax.swing.JViewport.paint(JViewport.java:722)
at javax.swing.JComponent.paintChildren(JComponent.java:647)
at javax.swing.JComponent.paint(JComponent.java:817)
at javax.swing.JComponent.paintChildren(JComponent.java:647)
at javax.swing.JComponent.paint(JComponent.java:817)
at javax.swing.JComponent.paintChildren(JComponent.java:647)
at javax.swing.JComponent.paint(JComponent.java:817)
at javax.swing.JLayeredPane.paint(JLayeredPane.java:557)
at javax.swing.JComponent.paintChildren(JComponent.java:647)
at javax.swing.JComponent.paintWithOffscreenBuffer(JComponent.java:4794)
at javax.swing.JComponent.paintDoubleBuffered(JComponent.java:4740)
at javax.swing.JComponent.paint(JComponent.java:798)
at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:21)
at
sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:60)
at
sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:97)
at java.awt.Container.paint(Container.java:1312)
at sun.awt.RepaintArea.paint(RepaintArea.java:177)
at sun.awt.windows.WComponentPeer.handleEvent(WComponentPeer.java:260)
at java.awt.Component.dispatchEventImpl(Component.java:3678)
at java.awt.Container.dispatchEventImpl(Container.java:1627)
at java.awt.Window.dispatchEventImpl(Window.java:1606)
at java.awt.Component.dispatchEvent(Component.java:3477)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)
six objects but if i change the tablesaveas method to this(see the below
code) the table is saved without any problems
Code:
public void tablesaveas ()
{
//This function saves the model of the table to disk using the user
//specified file name
//This is the function in which the exception is thrown
if(FileChooser1.showSaveDialog(fr) != JFileChooser.APPROVE_OPTION)
{
return;
}
try
{
File f = FileChooser1.getSelectedFile();
SF = (f.toString() + ".DAT");
FileOutputStream fStream = new FileOutputStream(SF);
ObjectOutput stream = new ObjectOutputStream(fStream);
//The below two command lines saves the table model and table column
data
//as an object using the user specified file name
stream.writeObject(Table1.getModel());
stream.writeObject(Table1.getColumnModel());
stream.flush();
stream.close();
fStream.close();
}
catch (Exception e)
{
Label1.setText("A table saving error has occurred");
}
}
The only difference as you can see is that i am writing two objects
instead of six and i don't really know what's wrong . I don't know if this
is a bug in Java or am i missing something.
I am using JDK 1.4.2_04
I hope someone can help me with this problem
Any help is greatly appreciated
Thank You
Yours Sincerely
Richard West