How to restart a JavaFX application when a button is clicked

Question

I went through almost every post here regarding the matter but most of them doesn\'t explain what to do properly. To the question:

I created a javaFX application, a

Answer 1

You already noticed that you cannot do the launching process again. Therefore your best option is to rewrite the application class and move the initialisation logic to a new method:

void cleanup() {
    // stop animations reset model ect.
}

void startGame(Stage stage) {
    // initialisation from start method goes here

    btnNewGame.setOnAction(e -> {
       restart(stage);
    });

    stage.show();
}

void restart(Stage stage) {
    cleanup();
    startGame(stage);
}

@Override
public void start(Stage primaryStage) {
    startGame(primaryStage);
}

Notes

• Depending on the parts of the scene changed, it may be enough to change the state of some of the nodes (more efficient than creating a new scene). (Just take a look at the changes you made during the game and decide for yourself)
• launch() is a static method and you should not create a instance of your application class yourself for that reason. Use Application.launch(GameUI.class, args); instead and let the method handle the creation of the GameUI instance.
• It may be a better design to move the UI creation to a class different to the application class. This way reuse of the code is easier, since it does not require the creation of a instance of a subclass of Application.