`UWebHUDWidget`

Source: SampleProject/Plugins/UnrealReactBridge/Source/UnrealReactBridge/Public/WebHUDWidget.h

UUserWidget subclass that hosts an embedded UBindableWebBrowser and manages the full bridge lifecycle (CEF load → BindUObject → ue5-bridge-ready → event queue flush). Create a Widget Blueprint child of this class for the widget-first authoring path.

UCLASS: Abstract, BlueprintType
Display name: Web HUD Widget Base
Parent path (BP): UMG → User Widget → Web HUD Widget Base

Required Designer wiring

Inside your WBP, place a Bindable Web Browser widget and name it WebBrowser exactly (case-sensitive BindWidgetOptional lookup). The base class binds window.ue.bridge to that widget after OnLoadCompleted. If the binding fails, you'll see an OnBridgeError with EBridgeErrorType::WebBrowserNull.

Properties

Property	Type	Category	Notes
`URL`	`FString` (`EditAnywhere`, `BlueprintReadWrite`)	Bridge	React app URL. If empty, falls back to Project Settings → Unreal React Bridge → Default Dev URL.
`BridgeName`	`FString` (`EditAnywhere`, `BlueprintReadWrite`)	Bridge	Optional name used by `Subsystem::SendEvent(BridgeName, ...)` to address this widget. Empty (default) = participates in `BroadcastEvent` only. Case-sensitive.
`InitialState`	`TMap<FString, FString>` (`EditAnywhere`, `BlueprintReadWrite`)	Bridge \| Initial State	Each value is treated as a JSON literal (object, array, number, string, bool, null). Values that fail to parse are wrapped as JSON strings. Delivered to React as `ue5-bridge-ready.detail.initialState[key]`. See `/guide/initial-state`.

Functions

Function	Signature	Notes
`SendEvent`	`void SendEvent(const FString& EventName, const FString& JsonData)`	Queues if React not yet ready; queue is flushed once on `OnReactReady`.
`LoadURL`	`void LoadURL(const FString& NewURL)`	Resets bridge state (`bIsReactReady = false`, clears pending queue) and re-initializes on `OnLoadCompleted`.
`IsReady`	`bool IsReady() const` (`BlueprintPure`)	Has React called `window.ue.bridge.ready()` (i.e. fired `onreactready`) yet?

`SendEvent`

cpp

void SendEvent(const FString& EventName, const FString& JsonData);

Param	Type	Required	Notes
`EventName`	`FString`	yes	Case-sensitive
`JsonData`	`FString`	yes	Valid JSON string; reaches React as `event.detail`

Returns — void. Fires synchronously if ready; otherwise enqueued and flushed when OnReactReady is invoked.

`LoadURL`

cpp

void LoadURL(const FString& NewURL);

Param	Type	Required	Notes
`NewURL`	`FString`	yes	New page URL (`http://`, `https://`, or `file:///`)

Returns — void. Triggers the full lifecycle again: page load → bridge re-bind → OnReactReady re-fires.

`IsReady`

cpp

bool IsReady() const;

Returns — true once React has called window.ue.bridge.ready() and the queued events have been flushed.

Delegates

All delegates are BlueprintAssignable and live under category Bridge.

Delegate	Signature	When
`OnReactReadyEvent`	`FOnHUDReactReady()`	React signaled ready, bridge live, queued events flushed
`OnEventReceived`	`FOnHUDEventReceived(const FString& EventName, const FString& JsonData)`	A React-side event arrived. Receiver components handle most cases; this delegate is for ad-hoc handling directly on the widget.
`OnBridgeError`	`FOnHUDBridgeError(const FBridgeErrorInfo& ErrorInfo)`	Any bridge error — see `/reference/types#fbridgeerrorinfo`

cpp

DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnHUDReactReady);
DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FOnHUDEventReceived,
    const FString&, EventName,
    const FString&, JsonData);
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnHUDBridgeError,
    const FBridgeErrorInfo&, ErrorInfo);

Lifecycle notes

The widget self-registers with UUnrealReactBridgeSubsystem in NativeConstruct and unregisters in NativeDestruct — you don't call any registration API yourself.
LoadURL restarts the full lifecycle: page reload → bridge re-bind → OnReactReadyEvent fires again. Any state held in React is lost; rehydrate via InitialState on the next ready.
NativeOnFocusReceived is overridden to forward keyboard focus down to the embedded SWebBrowser, since UMG container widgets don't normally pass focus to CEF.
The C++ class is Abstract — you cannot place it in the viewport directly; always subclass via a Widget Blueprint.

Example

text

WBP_MyHUD  (parent: Web HUD Widget Base)
└── WebBrowser  ← Bindable Web Browser widget (name MUST be "WebBrowser")

Class Defaults
  URL:         http://localhost:5173
  BridgeName:  MainHUD
  InitialState:
    "player" → {"name":"Alice","hp":100}
    "level"  → 7

text

Level Blueprint
  Event BeginPlay
    └─ Create Widget (Class: WBP_MyHUD)  → HudRef
    └─ Add to Viewport (Target: HudRef)

cpp

// C++: drive the widget after creation
if (UWebHUDWidget* Hud = CreateWidget<UWebHUDWidget>(GetWorld(), MyHudClass))
{
    Hud->InitialState.Add(TEXT("player"),
        TEXT("{\"name\":\"Alice\",\"hp\":100}"));
    Hud->AddToViewport();

    Hud->OnReactReadyEvent.AddDynamic(this, &AGameMode::HandleReactReady);
    Hud->OnEventReceived.AddDynamic(this, &AGameMode::HandleHudEvent);
}

UWebHUDWidget ​

Properties ​

Functions ​

SendEvent ​

LoadURL ​

IsReady ​

Delegates ​

Lifecycle notes ​

Example ​

See also ​