How to give an dynamicly loaded TreeViewItem an EventHandler? - dynamic

Question

at the moment i programm a database based Chat System.
The friendlist of every User gets loadet in a TreeView after the login.
means:
After the login I request the names of the useres friends by the following Funktion,
String namesSt[] = get.getUserFriendNameByUserID(currentUserID);
To use the given Names to load them as TreeItem into my Friendlist / TreeRootItem "rootItem"
for (int counter = 0; counter < namesSt.length; counter++) {
System.out.println(namesSt[counter]);
TreeItem<String> item = new TreeItem<String> (namesSt[counter]);
item.addEventHandler(MouseEvent.MOUSE_CLICKED,handler);
rootItem.getChildren().add(item);
}
When I now add my rootItem, I see the Names in the TreeView.
But if I click on a name, the given MouseEventHandler doesn´t get called.
Further I just want to request the text of the Element which trigger the MouseEvent, so that i can submit these name to a spezial funktion.
How can i realice such an MouseEvent?
How is it possible to call it from the dynamicly created TreeItem?
Thank you for any help :)
cheerse
Tobi

Answer 1

TreeItems represent the data, not the UI component. So they don't generate mouse events. You need to register the mouse listener on the TreeCell. To do this, set a cell factory on the TreeView. The cell factory is a function that creates TreeCells as they are needed. Thus this will work for dynamically added tree items too.
You will need something like this:
TreeView<String> treeView ;
// ...
treeView.setCellFactory( tv -> {
TreeCell<String> cell = new TreeCell<>();
cell.textProperty().bind(cell.itemProperty());
cell.addEventHandler(MouseEvent.MOUSE_CLICKED, event -> {
if (! cell.isEmpty()) {
String value = cell.getItem();
TreeItem<String> treeItem = cell.getTreeItem(); // if needed
// process ...
}
});
return cell ;
}