Components in Container

Vaadin 6 / 7 / 8 Framework UI
1

Hi folks,
maybe it is a silly question. I noticed that you can put components into a table. That’s a very useful thing. Because i want to put a button into my table. But i have a problem. In the example written in the VAADIN book the components are added directly to the table with addItem(Object[] cells, Object itemId)
. But in my special case i use a container. And not Container has such a method to override it. So how can i use a container and put components in a table?
Thanks for your help

With best regards

Aleks

2

Hi Aleksandar!

I resolved same kind of problem in below code.
Hope this help in your problem.


	/**
	 * Add new row to table container
	 * 
	 * @param container
	 * @param objects
	 */
	public static void addRow(Container container, Object oid, Object[] objects) {
		Item item = container.addItem(oid);
		int i = 0;
		for (Object id : container.getContainerPropertyIds()) {
			item.getItemProperty(id).setValue(objects[i++]
);
		}

	}

before that you have to add table header


container.addContainerProperty("header name", String.class, "");
3

John here has a fine solution on how to add items to a container.

All addItem or modify items etc. that you find in tables, selects and other components are just in fact wrapper functions for the container - everything done in those functions are actually done by calling the container directly. Every AbstractSelect extending Component (ie. Tree, Table, Select) has always a container where the items are in, even if you don’t specify one.

If we look into the code of the function
public Object addItem(Object[] cells, Object itemId)

, we’ll see how the table interacts with the container. Here’s the most important part of that function, rows 1656-1674 of Table in version 6.0.0 of Vaadin:

// Creates new item
Item item;
if (itemId == null) {
    itemId = items.addItem();
    if (itemId == null) {
        return null;
    }
    item = items.getItem(itemId);
} else {
    item = items.addItem(itemId);
}
if (item == null) {
    return null;
}

// Fills the item properties
for (int i = 0; i < availableCols.size(); i++) {
    item.getItemProperty(availableCols.get(i)).setValue(cells[i]
);
}

the field items refers to the container in the table. There is a lot of failsafe checks in that function, to handle different input, but basically by doing this you will do exactly the same as this function

Item item = container.addItem(itemId);
Collection columns = container.getContainerPropertyIds();
for (int i = 0; i < columns.size(); i++) {
    item.getItemProperty(columns.get(i)).setValue(cells[i]
);
}

(Pseudocode)

4

Thank you for this quick solution. If I get it right, you mean, adding a component like a button, TextField, Label doesn’t need any special implementation. These components will be added automatically to the table intern container. Because in John’s solution i don’t get the clue where the components are. In the object array? And can an item handle components as properties? So they will be shown on the table?

5

You got that right, any object will do fine as an item property, including Components. Well, I wouldn’t go and try adding Table components into another Table, that’s probably not a good idea :wink: (although tested to work, if I remember correctly)

Note, that this goes only for the Table component, other AbstractSelect implementations do not support adding Components as items (restriction mainly on the client-side rendering, not on the Java API level).