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?

What do you mean by "when I select a certain row, say row 5, it changes the row that's labeled 5" ? Does the displayed row changes or when you are trying to get the selected row you are getting a different one ? — prajeesh kumar, Feb 01 '12 at 05:09

score 5 · Answer 1 · answered Feb 01 '12 at 05:54

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 };

+1 for adjusting the model; a _numeric_ type is also possible. — trashgod, Feb 01 '12 at 10:51

score 3 · Answer 2 · answered Feb 01 '12 at 04:56

3

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.

answered Feb 01 '12 at 04:56

Amos M. Carpenter

4,848
4
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score 3 · Answer 3 · edited May 23 '17 at 11:51

3

To expand on @aaamos' answer, verify that your TableModel returns Number.class (or a suitable subclass) from getColumnClass(). There's a related example here.

edited May 23 '17 at 11:51

Community

1
1

answered Feb 01 '12 at 05:18

trashgod

203,806
29
246
1,045

score 1 · Answer 4 · answered Feb 01 '12 at 05:54

1

To meet your requirement, you just sets the Comparator for RowSorter to use when sorting the specified column. The code somewhat like below:

table.setAutoCreateRowSorter(true);
TableRowSorter<DefaultTableModel> rowSorter = (TableRowSorter<DefaultTableModel>)table.getRowSorter();
rowSorter.setComparator(5, new Comparator<String>() {

        @Override
        public int compare(String o1, String o2)
        {
            return Integer.parseInt(o1) - Integer.parseInt(o2);
        }

    });

answered Feb 01 '12 at 05:54

Alanmars

1,267
1
11
21

2

It is far better to adjust your `TableModel` – Robin Feb 01 '12 at 07:11
I can see the superficial appeal of this approach, but @Robin is right: The model should contain a _numeric_ type. – trashgod Feb 01 '12 at 10:57

score 0 · Answer 5 · answered Jul 01 '16 at 17:28

You must add the below code to your actual code that doesn't sort your column as Integer.

Your actual code to build your JTable is:

DefaultTableModel modeloT = new DefaultTableModel(); 
// But Sorts the column of numbers in wrong way. 1,11,2,25,......

SOLUTION:

DefaultTableModel modeloT = new DefaultTableModel() {

// Defining the type of column on your JTable. I wish sort my second column as a numeric (1,2,11), not String (1,11,2). For that I defined the second class as Integer.
Class[] types = { String.class, Integer.class, String.class };
boolean[] canEdit = new boolean [] {
    false, false, false
};

    // You must add this Override in order to works sorting by numeric.
@Override
public Class getColumnClass(int columnIndex) {
        return this.types[columnIndex];
        }       

     // This override is just for avoid editing the content of my JTable. 
@Override
public boolean isCellEditable(int row, int column) {
        return false;
        }
};

score 0 · Answer 6 · answered Jul 16 '16 at 15:55

I was also trying to achieve what you were trying to do and I struggled to understand how to do it myself. The way I achieved the "proper" sorting was as such:

DefaultTableModel model = new DefaultTableModel(row, col){
    @Overrride
     public Class getColumnClass(int c) {
         return getValueAt(0, c).getClass();
     }
});

Problems with JTable sorting of integer values

6 Answers6

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