Variable ' xxx ' have initializer but incomplete type

Error: Variable ' xxx ' have initializer but incomplete type
Reason: xxx corresponding type did not find, only the XXX declared but did not give a definition. The compiler has no way of confirming what constructor you are calling, where
Typically there is no header file that contains the definition xxx.

Like what:

1 MyClass theobj;2     Constqmetaobject* metaobj =Theobj.metaobject ();3     //1. Traversing the properties of a class4     intpropertycnt = metaobj->Propertycount ();5      for(inti =0; i < propertycnt; ++i)6     {7Qmetaproperty Oneproperty = metaobj->Property (i);8Std::cout <<"Name:"<<oneproperty.name ();9Std::cout <<"Type:"<< Qvariant::typetoname (Oneproperty.type ()) <<"\ n";Ten}

If you do not include a header file, the error will be reported:

Use # include <QMetaProperty>.

Variable ' xxx ' have initializer but incomplete type