在 QML 中使用 c++ 枚举作为字符串
我想做的是在 c++ 中使用以下枚举:
What I would like to do is use the below enum in c++:
class MyClass : public QQuickItem {
Q_OBJECT
Q_PROPERTY(MyEnum enumValue READ getEnumValue)
public:
enum MyEnum{
MyEnumElement = 0
};
Q_ENUM(MyEnum)
slots:
MyEnum getEnumValue(){
return enumValue;
}
private:
MyEnum enumValue = MyEnumElement;
};
QML 中的这种方式:
In such a way in QML:
MyClass {
id: myClass
}
Text {
text: "enumValue is: " + myClass.enumValue
}
这将导致 enumValue is MyEnumElement
而不是 enumValue is 0
现在就是这种情况.我现在的解决方案如下,但不优雅:
That would result in enumValue is MyEnumElement
instead of enumValue is 0
which is the case now. The solution I have now is the following, however inelegant:
class MyClass : public QQuickItem {
Q_OBJECT
Q_PROPERTY(MyEnum enumValue READ getEnumValue)
public:
enum MyEnum{
MyEnumElement = 0
};
Q_ENUM(MyEnum)
QMetaEnum MyEnum_MetaEnum = QMetaEnum::fromType<MyEnum>();
Q_INVOKABLE QString getEnumString(MyEnum enumVal){
return MyEnum_MetaEnum.valueToKey(enumVal);
}
slots:
MyEnum getEnumValue(){
return enumValue;
}
private:
MyEnum enumValue = MyEnumElement;
};
还有:
MyClass {
id: myClass
}
Text {
text: "enumValue is: " + myClass.getEnumString(myClass.enumValue)
}
有没有更好的方法来做到这一点?
Is there a better way to do this?
推荐答案
我发现以下方法可行:
class MyClass : public QQuickItem {
Q_OBJECT
Q_PROPERTY(QVariant enumValue READ getEnumValue)
public:
enum MyEnum{
MyEnumElement = 0
};
Q_ENUM(MyEnum)
slots:
QVariant getEnumValue(){
return QVariant::fromValue(enumValue);
}
private:
MyEnum enumValue = MyEnumElement;
};
QML 方面:
MyClass {
id: myClass
}
Text {
text: "enumValue is: " + myClass.enumValue.toString()
}
不使用 .toString()
仍会导致 QVariant
被强制转换为 int.我仍然愿意接受更优雅的解决方案.
Using without .toString()
still causes the QVariant
to be cast to an int. I'm still open to more elegant solutions.
正如预期的那样,这会破坏 QML/Javascript 端的 switch
和 ===
.switch(enumValue.valueOf())
和 ==
与 Q_ENUM()
导出的枚举整数比较时必须使用,例如 MyClass.MyEnumElement
:
As expected, this breaks switch
and ===
on the QML/Javascript side. switch(enumValue.valueOf())
and ==
must be used when comparing to enum ints exported by Q_ENUM()
, such as MyClass.MyEnumElement
:
switch(myClass.enumValue.valueOf()){
case MyClass.MyEnumElement:
...
break;
}
和
if(myClass.enumValue == MyClass.MyEnumElement)
...
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