Dynamically adding JTable to JScrollPane

Question

I have a table that I want to populate when the user prompts me to do so. Problem is, I can't anticipate how many rows the table will end up having. In the constructor for my panel where the table will be displayed I have

    // add empty scrollPane to JPanel which will later hold table
              scrollPane = new JScrollPane(); 
    add(scrollPane);

This class contains a method that will be called when I want to finally display the table

    public void displayTable(String[] columnNames, String[][] dataValues)
{
    table = new JTable(dataValues, columnNames);
    table.setPreferredScrollableViewportSize(new Dimension(300, 80)); 
    table.setFillsViewportHeight(true); 
    scrollPane.add(table);

    this.setVisible(true);
    scrollPane.repaint();

}

Problem is, the table never displays. I just see an outline of where the ScrollPane is with no table inside. Why isn't the table displaying and how can I fix it?

Answer 1

You should add component not to JScrollPane but to its JViewport:

scrollPane.getViewport ().add (table);

Answer 2

Instead of adding table to the JScrollPane Create a viewport of scrollpane and then sets its view as table. using following code instead:
scrollPane.setViewportView(table)

Answer 3

Generally, you create the JTable and the JScrollPane together, even though you have no values yet.

It's better to use a DefaultTableModel, or a TableModel that you extend, for a dynamic table.