Using the UMG MVVM system, is there anyway to bind yourself directly into the code, without going with the UI ?

Development Programming & Scripting
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1

Hello,

I’ve been fiddling with UMG and the MVVM plugin, which is quite nice !
I’m trying to replicate 2 things

  • First, being able to create, from C++, a variable that is set as Notify, so on the BluePrint or code side, I could broadcast the value. Whatever I’ve tried to do (Setting the FieldNotify parameter for exemple), I’m never able to “broadcast” my value, wheares on Blueprint, I can do it easely. Is that the normal behavior ?

  • Secondly, I would like directly from the code to listen to that value. Let’s say I don’t want to listen it from the UI, but from an other system (Like a statistics system). I’m trying my best, but I don’t see how I can “bind” myself to that broadcasted value ?

Thank you if you have any answer !

2

  1. How you are broadcasting a value in Blueprint? I think your confusion is that FieldNotify is for UI only, in C++ we use DELEGATES or Getter functions, for example.

  2. In C++ you can use DELEGATES:

MVVM.h

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FMyIntVariable, int32, Value);

public:
	UPROPERTY(BlueprintAssignable)
	FMyIntVariable OnVariableChange;

MVVM.cpp

{
	// when variable changes.
	OnVariableChange.Broadcast(Value);
}

Statistics.h

void OnMyIntChange(const int32 Value);

Statistics.cpp

MyMVVM->OnVariableChange.AddUniqueDynamic(this, &ThisClass::OnMyIntChange);

void AStatistics::OnMyIntChange(const int32 Value)
{
	// value changed.
}

You can bind OnVariableChange in Blueprint too because we are using BlueprintAssignable.