Loop and Break for Player UI Control

What you'll learn

You'll learn how the loop expression repeats a block indefinitely and how break exits it the instant a condition is met. To prove the technique end to end, you'll drive real player-UI calls (GetPlayerUI[...], AddWidget, and a text_block inside a canvas) so the loop actually does something visible.

How it works

• loop: repeats its block forever. Without a break or return, it never ends — an infinite loop.
• break immediately leaves the nearest enclosing loop. This is the whole point: stop as soon as you've found what you need instead of scanning the rest.
• We index into an array with Items[Index] — array indexing is fallible, so it must live inside a failure context (here, an if). If the index runs past the end, the if fails and we break out gracefully.
• GetPlayerUI[Player] is <decides> (fallible), so we bind it with [] inside an if. Once we have the player_ui, AddWidget shows our text on screen.

We compare item names with = (Verse equality — not ==) and increment our index with set Index = Index + 1 (there is no ++).

Let's build it

Press the button; the device loops through the item list, and the first time it matches "BananaOfTheGods" it pushes a text widget to every player and breaks. If it walks off the end of the list without a match, it shows a "not found" message and breaks too.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/UI }
using { /Fortnite.com/UI }

# Device that scans a list with loop/break and updates player UI.
loop_break_ui_device := class<concrete>(creative_device):

    # Button the player presses to start the scan.
    @editable
    TriggerButton : button_device = button_device{}

    # The item names we scan through, in order.
    ItemsToScan : []string = array{"Apple", "Banana", "BananaOfTheGods", "Bacon"}

    # The name we are hunting for.
    Target : string = "BananaOfTheGods"

    OnBegin<override>()<suspends>: void =
        # Fire ScanItems whenever the button is pressed.
        TriggerButton.InteractedWithEvent.Subscribe(OnButtonPressed)

    # Handler must take the interacting agent (button event payload).
    OnButtonPressed(Agent : agent): void =
        # Track where we are in the list. No ++ in Verse; use `set`.
        var Index : int = 0
        loop:
            # Array indexing is fallible; if we run past the end the if fails.
            if (ItemName := ItemsToScan[Index]):
                if (ItemName = Target):
                    # Found it — update the UI and leave the loop early.
                    ShowMessage("Found {ItemName}!")
                    break
                # Not this one; advance and keep looping.
                set Index = Index + 1
            else:
                # Reached the end without a match.
                ShowMessage("Target not found.")
                break

    # Adds a text_block (inside a canvas) to every player's screen.
    ShowMessage(Text : string): void =
        for (Player : GetPlayspace().GetPlayers()):
            # GetPlayerUI is <decides>; bind it with [] in a failure context.
            if (PlayerUI := GetPlayerUI[Player]):
                TextWidget := text_block{DefaultText := StringToMessage(Text)}
                Root := canvas{Slots := array{
                    canvas_slot{Widget := TextWidget}
                }}
                PlayerUI.AddWidget(Root)

    # Helper to build a message from a string via interpolation.
    StringToMessage<localizes>(Value : string): message = "{Value}"

Try it yourself

1. Place a Button device in your level and assign it to TriggerButton.
2. Build the Verse code and press the button in a playtest — you should see "Found BananaOfTheGods!" appear on screen.
3. Change Target to "Steak" (a value not in the list) and rebuild — now you'll see "Target not found." instead, because the loop reaches the end and takes the else branch.
4. Add a Print("Checking {ItemName}") line before the = comparison to watch the loop stop early once it hits the match.

Recap

• loop: runs forever until you break or return.
• break exits the nearest loop immediately — perfect for early exit on a match.
• Array indexing (Arr[i]) and GetPlayerUI[Player] are fallible: bind them in an if, and use the failure to detect "end of list" or "no UI".
• Mutate the index with set Index = Index + 1 and compare strings with =.
• Real UI happened here: we built a text_block in a canvas and called AddWidget on the player_ui.