JTable in JScrollpane adjust height of the displayed component

Question

I have a jtable within a jscrollpane. I use the jgoodies Form Layout and have put the scrollpane in a row that is set to "pref". This is how the table looks like right now:

I am using swingx JXTable by the way and have set the visibleRowCount to 2. But only half a row is displayed.

While making the SSCCE I realised that its not working properly because I have a custom TextAreaRenderer. I think because of this renderer, the row height is not being calculated properly. I am trying to figure out why, in the meantime if you guys can spot it that would be great...

public static void main(String[] args) {
    JFrame frame=new JFrame();
    JPanel panel=new FormDebugPanel();
    frame.setContentPane(panel);
    FormLayout layout=new FormLayout("1dlu:grow,200dlu:grow,1dlu:grow",
            "10dlu,pref,5dlu,pref,10dlu");
    panel.setLayout(layout);
    String[] columns= {"1st Column","2nd Column","3rd Column"};
    String[][] data= {
            {"Sethu","Data","Something\nis\nhere"},
            {"Sethu","Data","Something\nis\nhere"},

    };
    JXTable table=new JXTable(data,columns);
    table.setVisibleRowCount(2);

    TableColumnModel columnModel=table.getColumnModel();
    columnModel.getColumn(2).setCellRenderer(new TextAreaRenderer());

    JScrollPane scrlPan=new JScrollPane(table);
    CellConstraints cc=new CellConstraints();
    panel.add(scrlPan, cc.xy(2, 2));
    panel.add(new JLabel("Label After Table"),cc.xy(2,4));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
  }
}

And here's the renderer:

class TextAreaRenderer extends JTextArea implements TableCellRenderer {

private final DefaultTableCellRenderer adaptee = new DefaultTableCellRenderer();

/** map from table to map of rows to map of column heights */
private final Map<JTable,Map<Integer,Map<Integer,Integer>>> cellSizes = new HashMap<JTable,Map<Integer,Map<Integer,Integer>>>();

public TextAreaRenderer() {
    setLineWrap(true);
    setWrapStyleWord(true);
}

public Component getTableCellRendererComponent(//
        JTable table, Object obj, boolean isSelected, boolean hasFocus, int row, int column) {
    // set the colours, etc. using the standard for that platform
    adaptee.getTableCellRendererComponent(table, obj, isSelected, hasFocus, row, column);
    setForeground(adaptee.getForeground());
    setBackground(adaptee.getBackground());
    setBorder(adaptee.getBorder());
    setFont(adaptee.getFont());
    setText(adaptee.getText());

    // This line was very important to get it working with JDK1.4
    TableColumnModel columnModel = table.getColumnModel();
    setSize(columnModel.getColumn(column).getWidth(), 100000);
    int height_wanted = (int) getPreferredSize().getHeight();
    addSize(table, row, column, height_wanted);
    height_wanted = findTotalMaximumRowSize(table, row);
    if (height_wanted != table.getRowHeight(row)) {
        table.setRowHeight(row, height_wanted);
    }
    return this;
}

private void addSize(JTable table, int row, int column, int height) {
    Map<Integer,Map<Integer,Integer>> rows = cellSizes.get(table);
    if (rows == null) {
        cellSizes.put(table, rows = new HashMap<Integer,Map<Integer,Integer>>());
    }
    Map<Integer,Integer> rowheights =  rows.get(new Integer(row));
    if (rowheights == null) {
        rows.put(new Integer(row), rowheights = new HashMap<Integer,Integer>());
    }
    rowheights.put(new Integer(column), new Integer(height));
}

/**
 * Look through all columns and get the renderer. If it is also a
 * TextAreaRenderer, we look at the maximum height in its hash table for
 * this row.
 */
private int findTotalMaximumRowSize(JTable table, int row) {
    int maximum_height = 0;
    Enumeration<TableColumn> columns = table.getColumnModel().getColumns();
    while (columns.hasMoreElements()) {
        TableColumn tc = (TableColumn) columns.nextElement();
        TableCellRenderer cellRenderer = tc.getCellRenderer();
        if (cellRenderer instanceof TextAreaRenderer) {
            TextAreaRenderer tar = (TextAreaRenderer) cellRenderer;
            maximum_height = Math.max(maximum_height, tar.findMaximumRowSize(table, row));
        }
    }
    return maximum_height;
}

private int findMaximumRowSize(JTable table, int row) {
    Map<Integer,Map<Integer,Integer>> rows = cellSizes.get(table);
    if (rows == null)
        return 0;
    Map<Integer,Integer> rowheights = rows.get(new Integer(row));
    if (rowheights == null)
        return 0;
    int maximum_height = 0;
    for (Iterator<Map.Entry<Integer, Integer>> it = rowheights.entrySet().iterator(); it.hasNext();) {
        Map.Entry<Integer,Integer> entry = it.next();
        int cellHeight = ((Integer) entry.getValue()).intValue();
        maximum_height = Math.max(maximum_height, cellHeight);
    }
    return maximum_height;
}
}

When I use the TextAreaRenderer, then the setVisibleRowHeight() is not honoured correctly. I think it has something to do with not setting the row height properly in the renderer.

Answer 1

With JXTable, you can configure how many rows (or columns) to show initially:

    table.setVisibleRowCount(2)

Here's a quick snippet showing how-to set the initial size in terms of rows and dynamically update the pref height in a TableModelListener

    final JXTable table = new JXTable(3, 5);
    table.setVisibleRowCount(table.getRowCount());
    TableModelListener l = new TableModelListener() {

        @Override
        public void tableChanged(TableModelEvent e) {
            if (!(e.getType() == TableModelEvent.INSERT)) return;
            table.setVisibleRowCount(((TableModel) e.getSource()).getRowCount());
            RootPaneContainer frame = (RootPaneContainer) SwingUtilities.windowForComponent(table);
            ((JComponent) frame.getContentPane()).revalidate();
        }
    };
    table.getModel().addTableModelListener(l);
    Action insert = new AbstractAction("add row") {

        @Override
        public void actionPerformed(ActionEvent e) {
            ((DefaultTableModel) table.getModel()).addRow(new Object[] {});
        }
    };
    new Timer(500, insert).start();
    JComponent comp = new JPanel(new MigLayout());
    comp.add(new JScrollPane(table));
    JXFrame frame = wrapInFrame(comp, "visibleRowCount");
    show(frame, frame.getPreferredSize().width, frame.getPreferredSize().height * 4);

Answer 2

setPreferredScrollableViewportSize(Dimension)

is something you should look into. and here is a good tutorial : How to Use Scroll Panes

Answer 3

I believe you can use preferredSize, minSize and maxSize properties of the JSCrollPane to achieve this. If you set preferredSize to the minimum size you want and the maxsize to the maximum size you want, it should work.