如何多次添加具有不同信息的同一节点？ （JavaFX）

Question

I'm making a program which notifies me when a new episode of one of my series is uploaded, I have a built-in notification center, which stores the uploads. How I did this, was basically making a VBox, the NotificationPanel, then having a nLayout with basic things like a close-button, and every time I there is a new episode uploaded, add the nLayout with different name and text for each serie. But I've seen that this isn't "possible", because I get this error:

Exception in thread "JavaFX Application Thread" java.lang.IllegalArgumentException: Children: duplicate children added: parent = VBox@2168def7

Anyone knows how I can get this to work?

Answer 1

You cannot add the same node multiple times. Just create a new instance of your NotificationPanel for every notification

Answer 2

As comments say, you can't add the same instance of a class multiple times in your VBox.

Each time you catch your event (episode uploaded) what you can do is :

1. Retrieve your VBox
2. Create a new instance of a JavaFX container (for example : HBox, TextField, TextArea, TreeView etc...)
3. Populate this instance with information you want to show
4. Add this instance in you VBox

Btw, by doing this, you don't use the fancy Model-View binding mechanism of JavaFX. A better solution would be to have a model class with an ObservableList in which you could push an instance of an object made to contain the information of the uploaded episode, and bind this ObservableList to a ListView with a custom CellFactory to build the cells of your List the way you want.

You can find information about the binding mechanism here : http://docs.oracle.com/javafx/2/binding/jfxpub-binding.htm

You can find information about ListView and custom CellFactory here : http://docs.oracle.com/javafx/2/ui_controls/list-view.htm

Hope it helps :)

Answer 3

If I get you correctly you should probably create your own custom Node. For example by

public class EpisodeBox extends Vbox {
     public EpisodeBox(String name){
           getChildren().add(new Label(name));
           getChildren().add(new Button("Close"));
           // ... etc.
     }
}

As Kwoinkwoin stated you can then on each event create a new EpisodeBox and add this one to your Panel.