How can I display a new scene in JavaFX 2.2? For example after button click

Question

how to display new scene after button click in the main window, I want the main window and the new scene are in one stage. thx

Answer 1

You can change the scene by calling stage.setScene(new Scene(newContentParent));
I don't think you are quite asking for a complete scene change though as you "want the main window and the scene in one stage". The main window is a stage (as Stage extends Window). And a given stage can only contain one scene at a time (though you can swap it out by calling setScene as described earlier).
What I think you are really asking for how can you replace some content part of the active Scene on the Stage. To do that you can set a layout manager like a HBox or a BorderPane as the root of your scene, then change out the content of the layout manager. For example:
final BorderPane layout = new BorderPane();
layout.setCenter(new Label("Dogbert");
final Button nav = new Button("Next");
layout.setLeft(nav);
nav.setOnAction(new EventHandler<ActionEvent>() {
  @Override public void handle(ActionEvent actionEvent) {
    layout.setCenter(new Label("Dilbert"));       
});In the above short sample code, if you wanted to change the scene rather than the a pane, then you would call stage.setScene rather than layout.setCenter.
There is a complete executable example with multiple content panes and some styling here:
http://stackoverflow.com/questions/13556637/how-to-have-menus-in-java-desktop-application