Vaadin-动态生成表

Question

I have a Vaadin application. One of it's components is a table. I need a possibility to add as many columns as the user wants (well, let's say max. 20 at the moment) to that table. At the beginning, there are 5 colums, so in fact the user can add column 6 - 20. However, after doing "layout.addComponent(...)", this table is not editable any more.

I tried 2 things:

1. There is a variable which stores the current number of rows and is increased by 1 for every click on an "add" button. With every click, 1 column is added to the table.

2. Another idea was to hold the columns numbers in a variable (like idea 1) and the value of the cells somewhere in a Collection (whatever). After click on the "add" button, the whole table is removed, then all columns are added (all that have been there + a new one) and it is added to the layout.

However, none of these ideas works.

Any suggestions?

Answer 1

I think it should be enough to invoke addContainerProperty on the Container that is linked to your Table . Doing that should fire a PropertySetChangeEvent to the Table.

Unless, of course, if you have limited the visible columns using Table.setVisibleColumns .

If this doesn't help you, a piece of code could help solving the problem.

Answer 2

If MyContainer extends IndexedContainer, you have full freedom; just as a sample, I have Statistics which is simply (dynamic) Map serialized in ZooKeeper, and MyContainer listens to ZooKeeper changes:

public class MyContainer extends IndexedContainer {
    ...
    public void process(final ModelChangeEvent event) {
        ...
        for (Map.Entry<String, Long> entry : newTask.getCounters().entrySet()) {
            addContainerProperty(entry.getKey(), Long.class, 0L);
            Property property = getContainerProperty(taskName, entry.getKey());
            property.setValue(entry.getValue());
        }
        fireContainerPropertySetChange();
        ...
    }

When we add new (key, value) pair to Map, we will get new column automatically, where "key" is column title, and "value" is cell value. No needs to call "fire"; it will be called automatically by IndexedContainer implementation (check sources).