JTable in JScrollPane

Hi, I am using Java 1.4 swing package.
How can I make sure that a constant number of rows
(let's say 10) would be visible in the JTable?
I also need to set vertical scroll bar visible all the
time.

Thanks.
Sean
xzhang4Asked:
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MirecXPConnect With a Mentor Commented:
Hi Sean.

Are You still there ?

I think I've answered Your question, haven't I ?



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MirecXPCommented:
Hi Sean,

You must create Your own class inherited from JTable and then override method getPreferredScrollableViewportSize(), which returns preffered size of scrollable object. Typically it returns getPrefferedSize of component, so you must return your size. In this case we can return height of 10 rows.

Here is the class code:

class MyTable extends JTable {

  int rowsVisible = 10;

  MyTable (Object[][] rowData, Object[] columnNames) {
    super(rowData, columnNames);
  }

  public Dimension getPreferredScrollableViewportSize() {
    Dimension d = super.getPreferredScrollableViewportSize();
    d.height = rowsVisible * getRowHeight();
    return d;
  }

  public void setRowsVisible(int r) {
    rowsVisible = r;
  }

  public int getRowsVisible() {
    return rowsVisible;
  }

}


Now you can use it:
     ...
    Object[] myOptions = {
      "1","2","3"," 4"," 5"," 6"," 7"," 8"," 9"," 10",
      "11","12"," 13"," 14"," 15"," 16"," 17"," 18"," 19"," 20",
    };

    MyTable t = new MyTable(new Object[][] {
        {"1a", "1b"},
        {"2a", "2b"},
        {"3a", "3b"},
        {"4a", "4b"},
        {"5a", "5b"},
        {"6a", "6b"},
        {"7a", "7b"},
        {"8a", "8b"},
        {"9a", "9b"},
        {"10a", "10b"},
        {"11a", "11b"},
        {"12a", "12b"},
        {"13a", "13b"},
        {"14a", "14b"},
        {"15a", "15b"},
      }, new Object[] {"COL a", "COL b"}
    );

    //force vertical scrollbar using JScrollPane.VERTICAL_SCROLLBAR_ALWAYS
    JScrollPane sp = new JScrollPane(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
    sp.getViewport().add(t);
     ..
    insert sp into some panel...

I'm sure this helps.

Mirec
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