How to add an action event to JavaFX textfield for focus?

I have a textfield for Password that has the text "Password" written in it. I want to make it so that whenever the textfield is clicked or gets focused that the text "Username" is deleted. This is the code that I have tried so far:

Controller:

@FXML protected void deleteInitialText(ActionEvent event){
        passwordShown.focusedProperty().addListener((ov, oldV, newV) -> {
            if(newV){
                passwordShown.setText("");
            }
        });
    }

FXML:

<TextField fx:id = "passwordShown"
               text = "Password"
               GridPane.columnIndex="1"
               GridPane.rowIndex="2"
               onAction="#deleteInitialText"/>

However, this does not produce any results.