1.9 KiB
1.9 KiB
ArrayClamp
- 功能描述： 限定整数属性的值必须在指定数组的合法下标范围内，[0,ArrayClamp.Size()-1]
- 使用位置： UPROPERTY
- 引擎模块： Numeric Property
- 元数据类型： int32
- 限制类型： int32
- 常用程度： ★★★
限定整数属性的值必须在指定数组的合法下标范围内，[0,ArrayClamp.Size()-1]
测试代码：
public:
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = ArrayClampTest)
int32 MyInt_NoArrayClamp = 0;
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = ArrayClampTest, meta = (ArrayClamp = "MyIntArray"))
int32 MyInt_HasArrayClamp = 0;
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = ArrayClampTest)
TArray<int32> MyIntArray;
测试效果：
可见拥有ArrayClamp的整数值被限制在数组的下标中。
原理：
根据指定的数组名称在本类里寻找到Array属性，然后把本整数属性的值Clamp在该数组的下标范围内。
template <typename Type>
static Type ClampIntegerValueFromMetaData(Type InValue, FPropertyHandleBase& InPropertyHandle, FPropertyNode& InPropertyNode)
{
Type RetVal = ClampValueFromMetaData<Type>(InValue, InPropertyHandle);
//enforce array bounds
const FString& ArrayClampString = InPropertyHandle.GetMetaData(TEXT("ArrayClamp"));
if (ArrayClampString.Len())
{
FObjectPropertyNode* ObjectPropertyNode = InPropertyNode.FindObjectItemParent();
if (ObjectPropertyNode && ObjectPropertyNode->GetNumObjects() == 1)
{
Type LastValidIndex = static_cast<Type>(GetArrayPropertyLastValidIndex(ObjectPropertyNode, ArrayClampString));
RetVal = FMath::Clamp<Type>(RetVal, 0, LastValidIndex);
}
else
{
UE_LOG(LogPropertyNode, Warning, TEXT("Array Clamping isn't supported in multi-select (Param Name: %s)"), *InPropertyHandle.GetProperty()->GetName());
}
}
return RetVal;
}