JTable Cell Renderers

  To: comp.lang.java.gui
Hi everyone,

                    I am currently trying to use a JTextPane as a cell
renderers for a JTable but it does not seem to work although the program
compiles. I alsways get an error stating class cast exception saying that
i must cast the editor component to JTextField instead of a JTextPane
although i am using a JTextPane as a cell renderer.

                     This exeption gets thrown when i try to apply some
font to the selected text in the JTextPane.

                    Below is a small compilable that i have done which
compiles and throws the exception that i have mentioned about

Here is the compilable example

import java.awt.*;
import java.awt.image.*;
import java.io.*;
import java.text.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
import javax.swing.text.*;

public class TabTest implements ActionListener, ItemListener

{

    JFrame fr = new JFrame ("Frame");

    JButton Button1 = new JButton("Add Coloum");
    JButton Button2 = new JButton("Add Row");

    JComboBox ComboBox1;

    DefaultTableModel TableModel1 = new DefaultTableModel(0, 0);

    JTable Table1 = new JTable(TableModel1);

    JScrollPane ScrollPane1 = new JScrollPane(Table1,
ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
    ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);

    String FontFamily = "Arial";

    Dimension Size1 = new Dimension();

    //add
    //The below command line is the constructor for the JTextPane

    JTextPane TextPane1 = new JTextPane();

    //The below two command lines creates instances for fonts

    SimpleAttributeSet sas = new SimpleAttributeSet();

    StyleContext sc = new StyleContext();

    //The below command line sets up the variable for font updating

    MutableAttributeSet mas;

    //The below command line is the default document class which
    //has one argument as explained below
    //The first argument sets the Style Context of the styled document

    DefaultStyledDocument dse = new DefaultStyledDocument(sc);
    StyledEditorKit StyledEditorKit1 = new StyledEditorKit();

    CellPaneRenderer CellPaneRenderer1 = new CellPaneRenderer();
    //end

    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);
        Table1.setGridColor(Color.black);

        Size1.width = 350;
        Size1.height = 250;
        ScrollPane1.setPreferredSize(Size1);

        Table1.setModel(TableModel1);
        Table1.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        Table1.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);

        Table1.setDefaultRenderer(Object.class, new
CustomTableCellRenderer(Color.white));
        Table1.setDefaultRenderer(Object.class, new CellPaneRenderer());

        pane.add(ScrollPane1);
        pane.add(Button1);
        pane.add(Button2);
        combofontfamilyinitialize();
        pane.add(ComboBox1);

        fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Button1.addActionListener(this);
        Button2.addActionListener(this);

        ComboBox1.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 setAttributeSet(AttributeSet attr)
    {

        //This function only set the specified font set by the
        //attr variable to the text selected by the mouse

        int xStart, xFinish, k;

        xStart = TextPane1.getSelectionStart();
        xFinish = TextPane1.getSelectionEnd();
        k = xFinish - xStart;

        if(xStart != xFinish)
        {
            dse.setCharacterAttributes(xStart, k, attr, false);
        }

        else if(xStart == xFinish)
        {
            //The below two command line updates the JTextPane according to what
            //font that is being selected at a particular moment

            mas = StyledEditorKit1.getInputAttributes();
            mas.addAttributes(attr);
        }

    }

    public void insertcolumn (JTable table2)
    {
        //This function adds a column dynamically to the end of the JTable

        TableModel1 = (DefaultTableModel)table2.getModel();
        TableColumn col = new TableColumn(TableModel1.getColumnCount());

        //add
        col.setCellRenderer(CellPaneRenderer1);
        //end

        TableModel1.addColumn(" ");
        //The below command line adds the new column to the JTable

        table2.addColumn(col);

        TableModel1.fireTableStructureChanged();
    }

    public void actionPerformed(ActionEvent event)
    {
        JComponent b = (JComponent)event.getSource();
        int d;
        String str3 = null;
        String str4 = null, str5 = null;
        Object Object1 = null;
        Object Object2 = null;

        if(b == Button1)
        {
            //The below command line removes the cell editor of the JTable to
            //prevent any repitation of data from being added to the JTable

            Table1.removeEditor();

            insertcolumn(Table1);
        }

        else if(b == Button2)
        {
            //The below command line removes the cell editor of the JTable to
            //prevent any repitation of data from being added to the JTable

            Table1.removeEditor();

            //The below two command lines creates and adds an empty object
            //an a row into the current JTable

            Object[] v = new Object[0];
            TableModel1.addRow(v);
        }

    }
    public void itemStateChanged(ItemEvent event)
    {
        JComponent c = (JComponent)event.getSource();
        boolean d;

        if(c == ComboBox1)
        {
            Table1.editCellAt(0,0);
            FontFamily = (String)ComboBox1.getSelectedItem();
            TextPane1 = (JTextPane)Table1.getEditorComponent();

            if(TextPane1 != null)
            {
                StyleConstants.setFontFamily(sas, FontFamily);
                setAttributeSet(sas);
            }

        }

    }

    public static void main(String args[])
    {
        TabTest a = new TabTest();
        a.initialize();
    }
}

class CellPaneRenderer extends JTextPane implements TableCellRenderer
{

    public CellPaneRenderer()
    {

    }

    public Component getTableCellRendererComponent(JTable table, Object
value,
    boolean isSelected, boolean hasFocus,
    int row, int column)
    {

        setText((String)value);
        setSize(table.getColumnModel().getColumn(column).getWidth(),
getPreferredSize().height);

        if(table.getRowHeight(row) != getPreferredSize().height)
        {
            table.setRowHeight(row, getPreferredSize().height);
        }

        return this;

    }

}

Why this exception is occurring i am not very sure and really hope someone
can help me with this problem.

Any help is greatly appreciated

Thank You

Yours Sincerely

Richard West

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