How to delete the logical lines in JTextArea

Question

Hi all,
Now that I know how to find the logical line count in JTextArea as
I found the following in the forum.
public static int getLineCount (JTextArea _textArea)
boolean lineWrapHolder = _textArea.getLineWrap();
_textArea.setLineWrap(false);
double height = _textArea.getPreferredSize().getHeight();
_textArea.setLineWrap(lineWrapHolder);
double rowSize = height/_textArea.getLineCount();
return (int) (_textArea.getPreferredSize().getHeight() / rowSize);
I want to delete the 4th line to the last line and append ... at the 4th, if the getLineCount exceeds 3. Does any body know how to do so?
The intention is for the multiline tooltip as I just want to show
the first three logical line and ... if the string is too long.
Thanks
Pin

Answer 1

The code looks good to me. The only thought I have is that the y coordinate for the rowThree point is wrong and is referencing row four.
I've been playing around with using a JTextArea as a renderer for a JTable. I have it working so that "..." appear when the text exceeds 2 rows. Try clicking on "B" in the letter column and then the update cell button a few times to add text. My code is slightly different than yours.
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
public class TestTable extends JFrame
     private final static String LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
     JTable table;
     Vector row;
     public TestTable()
          Object[][] data = { {"1", "A"}, {"2", "B"}, {"3", "C"} };
          String[] columnNames = {"Number","Letter"};
          DefaultTableModel model = new DefaultTableModel(data, columnNames);
          table = new JTable(model)
               public String getToolTipText( MouseEvent e )
                    int row = rowAtPoint( e.getPoint() );
                    int column = columnAtPoint( e.getPoint() );
                    if (row == 0)
                         return null;
                    else
                         return row + " : " + column;
          table.setRowSelectionInterval(0, 0);
          table.setColumnSelectionInterval(0, 0);
          table.setRowHeight(0,34);
          table.setRowHeight(1,34);
          table.setRowHeight(2,34);
          table.setDefaultRenderer(Object.class, new TextAreaRenderer(2));
          JScrollPane scrollPane = new JScrollPane( table );
          getContentPane().add( scrollPane );
          JPanel buttonPanel = new JPanel();
          getContentPane().add( buttonPanel, BorderLayout.SOUTH );
          JButton button2 = new JButton( "Update Cell" );
          buttonPanel.add( button2 );
          button2.addActionListener( new ActionListener()
               public void actionPerformed(ActionEvent e)
                    int row = table.getSelectedRow();
                    int column = table.getSelectedColumn();
                    String value = (String)table.getValueAt(row, column);
                    value += value;
                    table.setValueAt( value, row, column );
                    DefaultTableModel model = (DefaultTableModel)table.getModel();
                    model.fireTableCellUpdated(row, column);
                    table.requestFocus();
     public static void main(String[] args)
          TestTable frame = new TestTable();
          frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
          frame.pack();
          frame.setVisible(true);
     private class TextAreaRenderer extends JTextArea implements TableCellRenderer
          public TextAreaRenderer(int displayRows)
               setRows(displayRows);
               setLineWrap( true );
          public Component getTableCellRendererComponent(JTable table,
                                         Object value,
                                         boolean isSelected,
                                         boolean hasFocus,
                                         int row,
                                         int column)
               setText( value.toString() );
               Dimension d = getPreferredSize();
               int maximumHeight = getRows() * getRowHeight();
               if (d.height > maximumHeight)
                    setSize(d);
                    int offset = viewToModel( new Point(d.width, maximumHeight - 1) );
                    replaceRange( "...", offset-3, getDocument().getLength() );
               return this;
}