5.5.2.1.43. Tree
The Tree
component is intended to display hierarchical structures represented by entities referencing themselves.
XML-name of the component: tree
The component is implemented for both Web Client and Desktop Client.
For the Tree
component, the datasource
attribute of the treechildren
element should contain a reference to a hierarchicalDatasource. Declaration of a hierarchicalDatasource
should contain a hierarchyProperty
attribute – the name of the entity attribute which is a reference to same entity.
Below is an example of the Tree
component description in a screen XML-descriptor:
<dsContext>
<hierarchicalDatasource id="departmentsDs" class="com.sample.sales.entity.Department" view="browse"
hierarchyProperty="parentDept">
<query>
select d from sales$Department d order by d.createTs
</query>
</hierarchicalDatasource>
</dsContext>
<layout>
<tree id="departmentsTree" width="100%" height="100%">
<treechildren datasource="departmentsDs" captionProperty="name"/>
</tree>
The name of the entity attribute to be displayed in the tree can be set using the captionProperty
attribute of the treechildren
element. If this attribute is not defined, the screen will show the entity instance name.
multiselect
attribute enables setting multiple selection mode for tree items. If multiselect
is true
, users can select multiple items using keyboard or mouse holding Ctrl or Shift keys. By default, multiple selection mode is switched off.
The setItemClickAction()
method may be used to define an action that will be performed when a tree node is double-clicked.
Each tree item can have an icon on the left. Create an implementation of the ListComponent.IconProvider
interface in the screen controller and set it for the tree:
@Inject
private Tree<Region> tree;
@Override
public void init(Map<String, Object> params) {
tree.setIconProvider(new ListComponent.IconProvider<Region>() {
@Nullable
@Override
public String getItemIcon(Region entity) {
if (entity.getParent() == null) {
return "icons/root.png";
}
return "icons/leaf.png";
}
});
}