Call order

Since the framework differentiates between initialization and rendering, different methods annotated with @OnInit or @OnRender are called at different times.

The framework has a general rule of initialization before rendering, meaning you cannot access most JavaFX elements (for example nodes defined in an FXML file) in the init methods as the elements aren’t loaded before the rendering.

When using subcomponents or For-Loops, the order of operations is a bit more complex. At first the main controller will be initialized. After the controller has been initialized, all subcomponents will be loaded and therefore initialized. This will happen recursively until a subcomponent doesn’t have any subcomponents. After that, the subcomponents will be rendered, going back up to the main controller. The main controller will be rendered, after all the subcomponents have been rendered.

If a For-Loop is defined in a method annotated with @OnRender in any (sub-)controller, the @OnRender will (obviously) be called first. After that, the initializer (BiConsumer) of the for-Controller will be called and then the for-controller will be initialized and then rendered.

Example

@Controller(view = "Example.fxml")
public class ExampleController {

    // Constructor, elements etc.
    // This controller has a subcomponent defined in the FXML file

    @OnInit
    public void init() {
        System.out.println("Init Controller");
    }

    @OnRender
    public void render() {
        System.out.println("Render Controller");
        fxFor.create(container, items, forControllerProvider, (controller, item) -> System.out.println("Initializer ForController"));
    }

}

@Component(view = "Sub.fxml")
public class SubController extends VBox {

    // Constructor, elements etc.
    // This controller has another subcomponent defined in the FXML file

    @OnInit
    public void init() {
        System.out.println("Init SubController");
    }

    @OnRender
    public void render() {
        System.out.println("Render SubController");
    }

}

@Component
public class ForController extends VBox {

    // Constructor, elements etc.

    @OnInit
    public void init() {
        System.out.println("Init ForController");
    }

    @OnRender
    public void render() {
        System.out.println("Render ForController");
    }

}

This setup results in the following outputs:

Constructor ExampleController
Init ExampleController
Constructor SubController
Init SubController
Constructor SubSubController
Init SubSubController
Render SubSubController
Render SubController
Render ExampleController
Constructor ForController
Initializer ForController
Init ForController
Render ForController

The destruction happens in the reverse order of the rendering.

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⬅ Subcomponents

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