How to set the RowHeight dynamically in a JTable

Question

I want to put a String in a JTable that is longer than the given cell-width. How can I set the rowHeight dynamically so that I can read the whole String? Here is an example:

import javax.swing.*;

public class ExampleTable {

public JPanel createTable() {               
    JPanel totalGUI = new JPanel();

    //define titles for table
    String[] title = {"TITLE1", "TITLE2", "TITLE3"};

    //table data
    Object[][] playerdata = {       
    {new Integer(34), "Steve", "test test test"},
    {new Integer(32), "Patrick", "dumdi dumdi dummdi dumm di di didumm"},
    {new Integer(10), "Sarah", "blabla bla bla blabla bla bla blabla"},};

    //create object 'textTable'
    JTable textTable = new JTable(playerdata,title);

    //set column width
    textTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF); 
    textTable.getColumnModel().getColumn(0).setPreferredWidth(60);
    textTable.getColumnModel().getColumn(1).setPreferredWidth(60);
    textTable.setDefaultRenderer(String.class, new RowHeightCellRenderer());

    //scrollbar
    JScrollPane scrollPane = new JScrollPane(textTable);

    totalGUI.add(scrollPane);               
    return totalGUI;
}

private static void createAndShowGUI() {

    //create main frame
    JFrame mainFrame = new JFrame("");
    ExampleTable test = new ExampleTable();

    JPanel totalGUI = new JPanel();
    totalGUI = test.createTable();

    //visible mode
    mainFrame.add(totalGUI); //integrate main panel to main frame
    mainFrame.pack();
    mainFrame.setVisible(true);     
}


public static void main (String[] args) {               

    createAndShowGUI();     

}//main
}

And here you'll see the code which line-breaks each text that is to long for the given cell

    import java.awt.*;
    import javax.swing.*;
    import javax.swing.table.*;


    public class RowHeightCellRenderer extends JTextArea implements TableCellRenderer
    {
      /**
         * 
         */
        private static final long serialVersionUID = 1L;

    public Component getTableCellRendererComponent (JTable table, 
                                                    Object value, 
                                                    boolean isSelected, 
                                                    boolean hasFocus, 
                                                    int row, 
                                                    int column )  {
        setText( value.toString() );    
        return this;
      }
    }

thank you but I want to implement the RowHeight dynamically, depending on String length... I want to read the whole String/text in the cell. any suggestions?

I'm java beginner and this is my first question. I would be delighted I get an answer.

Answer 1

There are several issues when using a JTextArea as rendering component (and most if not all of them already explained in several QA's on this site). Trying to sum them up:

Adjust individual row height to the size requirements of the rendering component

Basically, the way to go is to loop through the cells as needed, then

• configure its renderer with the data
• ask the rendering component for its preferred size
• set the table row height to the pref height

The updateRowHeight method in the OP's edited question is just fine.

JTextArea's calculation of its preferredSize

to get a reasonable sizing hint for one dimension, it needs to be "seeded" with some reasonable size in the other dimension. That is if we want the height it needs a width, and that must be done in each call. In the context of a table, a reasonable width is the current column width:

public Component getTableCellRendererComponent(JTable table,
        Object value, boolean isSelected, boolean hasFocus, int row,
        int column) {
    ... // configure visuals
    setText((String) value);
    setSize(table.getColumnModel().getColumn(column).getWidth(),
            Short.MAX_VALUE);
    return this;
}// getTableCellRendererComponent

Dynamic adjustment of the height

The row height it fully determined in some steady state of the table/column/model. So you set it (call updateRowHeight) once after the initialization is completed and whenever any of the state it depends on is changed.

// TableModelListener
@Override
public void tableChanged(TableModelEvent e) {
    updateRowHeights();
}

// TableColumnModelListener
@Override
public void columnMarginChanged(ChangeEvent e) {
    updateRowHeights();
}

Note

As a general rule, all parameters in the getXXRendererComponent are strictly read-only, implementations must not change any state of the caller. Updating the rowHeight from within the renderer is wrong.

Answer 2

I find it simplest to adjust the row height from inside the component renderer, like this:

public class RowHeightCellRenderer extends JTextArea implements TableCellRenderer
{
    public Component getTableCellRendererComponent(JTable table, Object 
            value, boolean isSelected, boolean hasFocus,
            int row, int column) {

        setText(value.toString());

        // Set the component width to match the width of its table cell
        // and make the height arbitrarily large to accomodate all the contents
        setSize(table.getColumnModel().getColumn(column).getWidth(), Short.MAX_VALUE);

        // Now get the fitted height for the given width
        int rowHeight = this.getPreferredSize().height;

        // Get the current table row height
        int actualRowHeight = table.getRowHeight(row);

        // Set table row height to fitted height.
        // Important to check if this has been done already
        // to prevent a never-ending loop.
        if (rowHeight != actualRowHeight) {
           table.setRowHeight(row, rowHeight);
        }

        return this;
    }
}

This will also work for a renderer which returns a JTextPane.