How to focus a specific node when selected tab changes in JavaFX?

Question

I want to set focus to a specific node in the content of a Tab. I added a ChangeListener to selectedItem property as follows (assume that the class contains a field named secondNode of type Node):

tabPane.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<Tab>() {
    @Override
    public void changed(ObservableValue<? extends Tab> observable, Tab oldValue, Tab newValue) {
        if (newValue != null) {
            Platform.runLater(new Runnable() {
                @Override
                public void run() {
                    secondNode.requestFocus();
                }
            });
        }
    }
});

However, this does not work. I assume the reason is because TabPane performs some additional actions, which affect focus, after the new tab has been selected (but, looking through TabPane source code, I can't figure out what). If I single-step through this code in a debugger, it works as expected, so it appears to be a race condition. If this is so, how can this be resolved?

Jurgen Jurgen · Accepted Answer · 2014-01-16T06:20:29

You could try replacing the Runnable with a Task:

        new Thread( new Task<Void>() 
        {
            @Override
            public Void call() throws Exception // This is NOT on FX thread 
            {
                Thread.sleep(100);
                return null;
            }

            @Override
            public void succeeded()  // This is called on FX thread.
            {
                secondNode.requestFocus();
            }

        }).start();

How to focus a specific node when selected tab changes in JavaFX?

1 Answers