Problems with JTable sorting of integer values

Question

Currently I have a JTable that uses RowSorter, but when I click the header that I want it to sort in, it displays the rows in a weird order

• 1
• 10
• 11
• ...
• 2
• 20
• 21
• ...
• 3
• 30

Yet when I select a certain row, say row 5, it changes the row that's labeled 5. Any reason as to why this is happening and how I can fix it?

Answer 1

You can set the column type for a JTable by setting its model explicitly like in the following example

setModel(new DefaultTableModel(new Object[0][], new String[] {
                "SELECT", "WHERE", "FIELD", "TYPE" }) {
            Class[] types = { Boolean.class, Boolean.class, String.class,
                    String.class };
            boolean[] canEdit = { true, false, false, false };

            @Override
            public Class getColumnClass(int columnIndex) {
                return this.types[columnIndex];
            }

            public boolean isCellEditable(int columnIndex) {
                return this.canEdit[columnIndex];
            }
        });

Give your column classes like this (here column one and two are Boolean and the rest String.

 Class[] types = { Boolean.class, Boolean.class, String.class,String.class };

Answer 2

You're treating the row contents as text. Your sort order is alphabetical rather than numerical. If you treat the contents as numbers it should work itself out.