How to trigger event when double click on a tree node

Question

I have this code which creates new tab in a remote Java Class.

treeView.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<TreeItem<String>>()
        {
            @Override
            public void changed(ObservableValue<? extends TreeItem<String>> observable, TreeItem<String> oldValue, TreeItem<String> newValue)
            {
                System.out.println("Selected Text : " + newValue.getValue());
                // Create New Tab
                Tab tabdata = new Tab();
                Label tabALabel = new Label("Test");
                tabdata.setGraphic(tabALabel);

                DataStage.addNewTab(tabdata);
            }
        });

Can you tell me how I can modify the code to open new tab when I double click on a tree node. In my code the tab is opened when I click once. What event handler do I need?

Solution 1

You can add an EventHandler<MouseEvent> to the TreeView.setOnMouseClicked() method and check for the getClickCount() return value of the MouseEvent to determine if it was a double click. Remove the ChangeListener above and add the logic to the EventHandler.

Use the description here and apply it to your treeView variable.

It'll look something like this. You'll probably want to check the item for null as well.

treeView.setOnMouseClicked(new EventHandler<MouseEvent>()
{
    @Override
    public void handle(MouseEvent mouseEvent)
    {            
        if(mouseEvent.getClickCount() == 2)
        {
            TreeItem<String> item = treeView.getSelectionModel().getSelectedItem();
            System.out.println("Selected Text : " + item.getValue());

            // Create New Tab
            Tab tabdata = new Tab();
            Label tabALabel = new Label("Test");
            tabdata.setGraphic(tabALabel);

            DataStage.addNewTab(tabdata);
        }
    }
});

Solution 2

In my opinion, the best practice is to implement your cell.

public class DoubleClickCellImpl extends TreeCell<String> {
    @Override
    protected void updateItem(String item, boolean empty) {
        super.updateItem(item, empty);

        if (item == null || empty) {
            setText(null);
        } else {
            setText(item);
        }
    }

    public DoubleClickCellImpl() {
        super();

        setOnMouseClicked(event -> {
            TreeItem<String> ti = getTreeItem();
            if (ti == null || event.getClickCount() < 2)
                return;

            // do something here.
        });
    }
}