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Sometimes I get a question on stack overflow that triggers a “yes this should be easy” reflex. I got such a question a couple of weeks ago when I implemented the animated gif support cn1lib and I had another one last week which asked about sorting tables.

This is actually pretty easy to do but it’s just something we didn’t get around to. So I just implemented it and decided this would make a lot of sense in the core API. Sortable tables make a lot of sense and ideally should be the default.

So I added support for this directly into Codename One and you can now make a table sortable like this:

Form hi = new Form("Table", new BorderLayout());
TableModel model = new DefaultTableModel(new String[] {"Col 1", "Col 2", "Col 3"}, new Object[][] {
    {"Row 1", "Row A", 1},
    {"Row 2", "Row B", 4},
    {"Row 3", "Row C", 7.5},
    {"Row 4", "Row D", 2.24},
    });
Table table = new Table(model);
table.setSortSupported(true);
hi.add(BorderLayout.CENTER, table);
hi.add(NORTH, new Button("Button"));
hi.show();

Notice this works with numbers, Strings and might work with dates but you can generally support any object type by overriding the method protected Comparator createColumnSortComparator(int column) which should return a comparator for your custom object type in the column.

Archived Comments

This post was automatically migrated from the legacy Codename One blog. The original comments are preserved below for historical context. New discussion happens in the Discussion section.

Francesco Galgani — August 16, 2017 at 4:59 pm (permalink)

Francesco Galgani says:

Thank you very much! 🙂

Francesco Galgani — August 16, 2017 at 5:11 pm (permalink)

Francesco Galgani says:

First question: I tested your code in a new Netbeans project, but it doesn’t compile because it «cannot find symbol table.setSortSupported(true);». I’ve seen that you updated the API, but… how do I update Netbeans?

Second question: in your code, is the Table sorted by the third column? How can I choose which column to order by?

Thank you for any help (and for your work in vacation time…)

Shai Almog — August 17, 2017 at 4:39 am (permalink)

Shai Almog says:

Make sure to update the libraries by opening Codename One Settings -> Basic -> Update Client Libs.

Francesco Galgani — August 17, 2017 at 9:35 am (permalink)

Francesco Galgani says:

Ok, now it compiles… but the table is not sorted (using exactly your code). How can I sort it according to the values in third column? Thank you

Shai Almog — August 18, 2017 at 5:53 am (permalink)

Shai Almog says:

Click the columns to sort them and again to flip ascending/descending direction.

salah Alhaddabi — August 21, 2017 at 4:44 am (permalink)

salah Alhaddabi says:

Very nice you guys are amazing!!!

SoAppMedia — August 21, 2017 at 4:42 pm (permalink)

SoAppMedia says:

Thanks for sharing! this is such a great help this is worth to share!

Francesco Galgani — August 21, 2017 at 5:02 pm (permalink)

Francesco Galgani says:

Ok. Is there any way to get a column already selected for ordering (in ascending or descending direction) before any user input, for example on myForm.show or myForm.revalidate()?

Shai Almog — August 22, 2017 at 5:27 am (permalink)

Shai Almog says:

I’ll add a sort(column, ascending) method to allow this.

Francesco Galgani — August 22, 2017 at 11:13 am (permalink)

Francesco Galgani says:

Thank you! 😀

Discussion

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