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UI

The engine.ui() component adds support for interactive menus and user notifications.

You can also use the UI to create a basic user interface. To create a custom menu extend the abstract UiMenu class.

OptionsMenu.java
public class OptionsMenu extends UiMenu {

    public OptionsMenu() {
        addItem("start new game")
          .onActivate(engine -> engine.scenes().switchTo(GameScene.class));
          
        addItem("quit")
          .onActivate(engine -> engine.stop());
    }
}
ui.openMenu(new OptionsMenu());

Inline definition​

It's also possible to define your menu inline:

InlineExample.java
ui.openMenu(menu -> {
    menu.addItem("goto fullscreen")
            .onActivate(engine -> engine.graphics().configuration().toggleFullscreen());
    menu.addItem("quit")
            .onActivate(Engine::stop);
});

Dynamic labels and disabled items​

Menu items can use dynamic labels. These labels will be refreshed on every frame. Also menu items can be disabled on condition. The condition will be checked on every frame.

// disabled on fullscreen
menu.addItem("goto fullscreen")
        .onActivate(engine -> engine.graphics().configuration().toggleFullscreen())
        .activeCondition(engine -> !engine.graphics().configuration().isFullscreen());
        
// dynamic label
menu.addItem(engine -> "current fps: " + engine.loop().fps())
        .onActivate(Engine::stop);

To create sub menus you can always go to the last menu opened.

addItem("back").onActivate(engine -> engine.ui().openPreviousMenu());
addItem("close").onActivate(engine -> engine.ui().closeMenu());

You can also add your own reactions when exiting a menu. To do so overwrite the onExit-method.

Customizing menus​

You can customize menus to your needs. To do so simply inject your own UiInteractor, UiLayouter and UiRenderer:

engine.ui()
    .setInteractor(new KeyboardAndMouseInteractor())
    .setLayouter(new WobblyUiLayouter())
    .setRenderer(new SimpleUiRenderer());

Notifications​

You can use the Ui to show notifications. You can specify the shown text and a sound effect that is played.

engine.ui().showNotification(NotificationDetails
    .text("Something happened!")
    .sound(SoundBundle.NOTIFY)
    .icon(SpriteBundle.EXPLOSION));

Notifications are automatically rendered by the RenderNotificationsSystem that is one of the default systems enabled using environment.enableAllFeatures().

You can customize rendering and layout using your own implementations:

ui.setNotificationRender(new MyRender())
ui.setNotificationLayouter(new MyLayouter());