Menus & Widgets

This document will cover the most important things to know about how the widget system is set up, and how you can best utilize the tools and functions within.

---

Overview

There exists a class called UMainWidget. This widget is on screen permanently and is the base from which all other widgets are added and shown. As such, AArsenicPlayerController has a reference to this widget so we can access its functions at any time from anywhere. The various functions that live on this widget help with adding and removing widgets to/from the screen, setting input modes, and handling the mouse cursor. Most of that is handled automatically when you call PushWidgetToTargetStack. The main widget has 4 stacks that you can push menus to:

• HUD_Stack (which is pretty much used only once to add the HUD),
• InteractableHUD_Stack (for drag and drop inventories and such),
• Menu_Stack (for menus like a pause menu or settings menu), and the
• Popup_Stack (for context widgets).

For more details, go to UI->Widgets->MainWidget.h

The Common UI plugin has also been set up to detect which input device is being used, and UCommonActionWidgets set input icons automatically based on those input types. Conveniently, I've created a UBottomNavBarBase class that can be added to any UArsenicMenuBase (important, it MUST be UArsenicMenuBase) that contains a button that will handle closing the current widget. It works like you'd expect a back button to.

---

Input

When a menu is opened, we must call SwitchToMenuInput() on the ArsenicPlayerController. This removes the Gameplay Input Mapping Context which moves the character, and replaces it with the Menu Input Mapping Context which helps with navigating menus. When MainWidget no longer has any widgets pushed, it broadcasts OnStacksCleared which the PlayerController responds to by calling SwitchToGameplayInput(). UI inputs are in _GAME->UI->Input->InputActions, and gameplay inputs are in _GAME->Blueprints->Player->Input->InputActions

Widgets can't (and won't) behave as expected when using traditional Input Actions directly in the widget because of a bug in the engine version we're using. Instead, menus have to respond to input by responding to delegates broadcast by the ArsenicPlayerController. For example, to tab left or tab right, the ArsenicPlayerController broadcasts that one of those inputs has been pressed. Then, the Settings menu responds by changing the widget index. Callbacks are set up in blueprint so we can access various widget components more easily, but the broadcasts themselves are handled in C++ by the ArsenicPlayerController.

Common UI supports global back actions, and our menu system makes great use of them. If you're creating a menu that you'll want to close by simply pressing B on controller or ESC, inherit from UArsenicMenuBase. This automatically responds to back actions, but requires that IsModal and IsBackHandler are set to true. You can find these bools in the widget's details panel. When you inherit from UArsenicMenuBase, you can also add a UBottomNavBarBase widget to add a clickable back button and navigation icons that change based on the current input device.

---

Focus

Focus is used to allow controllers to navigate menus, and is also one of the strongest points of frustration in UMG. We will be dealing with this for the duration of the project, so make sure you follow these steps to minimize frustration and maximize functionality. In the details panel of your widget blueprint:

• Set IsFocusable to true, and ensure the DesiredFocusWidget is set to self (or a button depending on your menu)
• Supports Activation Focus should be true, and depending on your menu, Auto Restore Focus should be true as well but is not required.
• Ensure the Input Config is set to Game and Menu and that Game Mouse Capture Mode is set to No Capture.
• Lastly, in the widget blueprint's event graph, override the GetDesiredFocusTarget function and set the return value to either Self or a button in your widget hierarchy. Then OnActivated, call SetFocus - the target is GetDesiredFocusTarget. You may have to add a small delay to account for widget transition animation time. This is displayed in WB_PauseMenu and WB_SettingsMenu, with the settings menu having tabbed navigation and sub-widget input logic.