61 lines
1.9 KiB
Markdown
61 lines
1.9 KiB
Markdown
|
# 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：
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
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。
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
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;
|
|||
|
|
}
|
|||
|
|
```
|