Add a row to a grid when a row edit is committed

In order that editing a grid might resemble editing a table in SQL Server Studio, I would like to add a 'blank' row to the bottom of a grid.  When this row is edited and saved with actual values, a new 'blank' row would be added on.  Adding an item to the Grid inside the CommitListener always fails.  Am I asking the impossible?  Is there a suggested strategy for dynamically modifying the Grid based on edit actions?

Hi,

you should be able add a new item to the Grid's container in a CommitHandler. If you're using something like a BeanItemContainer, make sure that you're actually adding a new object and not just re-adding the same object you just edited.

Here's an example:
https://github.com/OlliTietavainenVaadin/GridDemo/blob/master/src/main/java/com/vaadin/MyUI.java

Best regards,
Olli Tietäväinen
Vaadin Developer

When I do something like this:

                IndexedContainer source = (IndexedContainer) grid.getContainerDataSource();
                source.addItem();

inside the postCommit(), the propertyDataSource comes up null in FieldGroup.commitTransactions().  
Am I doing it wrong?

Hi,

It depends on the details of the rest of your code. Not all datasources support addItem, for example, although I suppose that's not your problem if you're getting a null from getContainerDataSource. I don't know if there's any reason why getContainerDataSource shouldn't work inside the commit listener, but maybe try accessing the datasource with some other means like by adding it as a member variable with a getter.

-Olli