64 lines
2.2 KiB
Markdown
64 lines
2.2 KiB
Markdown
|
# EditFixedOrder
|
|||
|
|
|
|||
|
|
- **功能描述：** 使数组的元素无法通过拖拽来重新排序。
|
|||
|
|
- **使用位置：** UPROPERTY
|
|||
|
|
- **引擎模块：** Container Property
|
|||
|
|
- **元数据类型：** bool
|
|||
|
|
- **限制类型：** TArray
|
|||
|
|
- **常用程度：** ★★
|
|||
|
|
|
|||
|
|
## 测试代码：
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = EditFixedOrderTest)
|
|||
|
|
TArray<int32> MyIntArray_NoEditFixedOrder;
|
|||
|
|
|
|||
|
|
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = EditFixedOrderTest, meta = (EditFixedOrder))
|
|||
|
|
TArray<int32> MyIntArray_EditFixedOrder;
|
|||
|
|
|
|||
|
|
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = EditFixedOrderTest)
|
|||
|
|
TSet<int32> MyIntSet_NoEditFixedOrder;
|
|||
|
|
|
|||
|
|
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = EditFixedOrderTest, meta = (EditFixedOrder))
|
|||
|
|
TSet<int32> MyIntSet_EditFixedOrder;
|
|||
|
|
|
|||
|
|
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = EditFixedOrderTest)
|
|||
|
|
TMap<int32,FString> MyIntMap_NoEditFixedOrder;
|
|||
|
|
|
|||
|
|
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = EditFixedOrderTest, meta = (EditFixedOrder))
|
|||
|
|
TMap<int32,FString> MyIntMap_EditFixedOrder;
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
## 测试效果：
|
|||
|
|
|
|||
|
|
- 可见只有第一个MyIntArray_NoEditFixedOrder，在数组元素上出现可拖拽的标记，然后可以改变顺序。
|
|||
|
|
- 加上EditFixedOrder的TArray就无法改变顺序了。
|
|||
|
|
- 其他TSet，TMap是不支持该meta的，因为其内部本身顺序也无关。
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
## 原理：
|
|||
|
|
|
|||
|
|
可以看见，细节面板里一个属性行是否可重排序的判断是外部是个数组，且没有EditFixedOrder和ArraySizeEnum（固定数组）。当然本身这个属性也要在可编辑状态（比如被禁用灰掉就显然不可编辑了）
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
bool FPropertyNode::IsReorderable()
|
|||
|
|
{
|
|||
|
|
FProperty* NodeProperty = GetProperty();
|
|||
|
|
if (NodeProperty == nullptr)
|
|||
|
|
{
|
|||
|
|
return false;
|
|||
|
|
}
|
|||
|
|
// It is reorderable if the parent is an array and metadata doesn't prohibit it
|
|||
|
|
const FArrayProperty* OuterArrayProp = NodeProperty->GetOwner<FArrayProperty>();
|
|||
|
|
|
|||
|
|
static const FName Name_DisableReordering("EditFixedOrder");
|
|||
|
|
static const FName NAME_ArraySizeEnum("ArraySizeEnum");
|
|||
|
|
return OuterArrayProp != nullptr
|
|||
|
|
&& !OuterArrayProp->HasMetaData(Name_DisableReordering)
|
|||
|
|
&& !IsEditConst()
|
|||
|
|
&& !OuterArrayProp->HasMetaData(NAME_ArraySizeEnum)
|
|||
|
|
&& !FApp::IsGame();
|
|||
|
|
}
|
|||
|
|
```
|