RE: How to know row index of selected item in Grid

Vaadin 6 / 7 / 8
1

Hi,

I believe this GitHub issue is relevant to your question:
https://github.com/vaadin/framework/issues/8820

(note also the included workaround there)

-Olli

2

Vaadin Grid has:

public void scrollTo(int row, ScrollDestination destination)

What way to know “zero based index of the item” which selected?

3

In this Issue and workaround no solution to get “row index”.

4

Right, the workaround is only for opening the editor. But as the original text message reads,
This would require also scrollToItem(T item) to work also
. That’s something that is currently missing (and the ticket is still open). You might want to comment or thumbs-up on the ticket to let people know that it’s needed.

-Olli

5

If items for grid from ArrayList (grid.setItems), this way to scroll is working:

ListDataProvider listDataProvider = (ListDataProvider) grid.getDataProvider();
ArrayList items = (new ArrayList(listDataProvider.getItems()));
int index = items.indexOf(item);
grid.scrollTo(index, ScrollDestination.END);
6

Good thinking. However, there should probably be a better way to do it, it doesn’t feel good to need to rely on implementation details like that.

-Olli

7

Problem to know row index for Grid with “com.vaadin.data.provider.CallbackDataProvider”:


grid.setDataProvider(
    (sortOrders, offset, limit) ->
            service.findAll(offset, limit).stream(),
    () -> service.count()
);
8
const gridSelectedColumn = parentElement.querySelector('vaadin-grid-selection-column'); gridSelectedColumn.renderer = (cell, column, rowData) => { 
                let checkbox = cell.firstElementChild;
                if (!checkbox) {
                    checkbox = document.createElement('vaadin-checkbox');
                    checkbox.setAttribute('aria-label', 'Select Row');
                    checkbox.addEventListener('change', (e) => {
                        let operation;
                        if (e.target.checked === false) {
                            operation = 'CANCEL';
                            this.rootElement.deselectItem(checkbox.__item);
                        } else {
                            operation = 'SELECT';
                            this.rootElement.selectItem(checkbox.__item);
                        }
                        this.rootElement.render();
                        let selectedLength = this.rootElement.selectedItems.length;
                    });
                    cell.appendChild(checkbox);
                }
                checkbox.__item = rowData.item;
                checkbox.checked = rowData.selected;
                rowData.item.index = rowData.index;
            };

for (let selectedItem of grid.selectedItems) {
// selectedItem.index is selected index
}

9 
ListDataProvider listDataProvider = (ListDataProvider) grid.getDataProvider();
ArrayList items = (new ArrayList(listDataProvider.getItems()));
int index = items.indexOf(item);
grid.scrollTo(index, ScrollDestination.END);

This does not work correctly if you sort or filter your grid.