Vaadin table | How to set colspan - vaadin

Question

I'm using vaadin tree table, and I want to set 1st column colspan (equal to the total number of column in table) for some of the rows satisfying some business criteria. For the rest of table rows, individual columns will appear normally.
I've tried using generated columns, and by setting explicit column width, and also by having composite columns; but doing so changes the layout for all the row/columns. Kindly suggest how will we achieve this.
Thanks!

Answer 1

You can set the width of a column by calling TreeTable#setColumnExpandRatio(String columnName, float value).
In the example below, I've set the width of column "Name" to 75%. If you don't specify anything else, the rest of the columns will fit in the rest of the space.
ttable.setColumnExpandRatio("Name", 0.75f);
ttable.setColumnExpandRatio("Number", 0.25f); //not necessary
Try the example below that I modified from Vaadin book:
#Theme("mytheme")
public class MyUI extends UI {
#Override
protected void init(VaadinRequest vaadinRequest) {
final VerticalLayout layout = new VerticalLayout();
layout.setSizeFull();
TreeTable ttable = new TreeTable();
ttable.addContainerProperty("Name", String.class, null);
ttable.addContainerProperty("Number", Integer.class, null);
//Add some sample data
ttable.addItem(new Object[]{"Menu", null}, 0);
ttable.addItem(new Object[]{"Beverages", null}, 1);
ttable.setParent(1, 0);
ttable.addItem(new Object[]{"Foods", null}, 2);
ttable.setParent(2, 0);
ttable.addItem(new Object[]{"Coffee", 23}, 3);
ttable.addItem(new Object[]{"Tea", 42}, 4);
ttable.setParent(3, 1);
ttable.setParent(4, 1);
ttable.addItem(new Object[]{"Bread", 13}, 5);
ttable.addItem(new Object[]{"Cake", 11}, 6);
ttable.setParent(5, 2);
ttable.setParent(6, 2);
ttable.setColumnExpandRatio("Name", 0.75f);
ttable.setColumnExpandRatio("Number", 0.25f);
ttable.setSizeFull();
layout.addComponents(ttable);
layout.setMargin(true);
layout.setSpacing(true);
setContent(layout);
}
#WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
#VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
public static class MyUIServlet extends VaadinServlet {
}
}

Answer 2

You can use com.vaadin.ui.Table.setRowGenerator:
Example with Java 8 + Vaadin 7.6.1
setRowGenerator((Table table, Object itemId) -> {
if (itemId instanceof MyClassThatIdentifiesARowToMerge) {
Table.GeneratedRow generatedRow = new Table.GeneratedRow("text-of-merged-cell");
generatedRow.setSpanColumns(true);
return generatedRow; // merge
}
return null; // doesn't merge
} );