Qvariant Saving pointer data

Qvariant The pointer data cannot be saved by default because the Qvariant constructor with the void * parameter is private.

However, with the meta-type mechanism provided by QT, arbitrary pointers can be stored in the qvariant.

You need to register the type with the Q_declare_metatype macro.

123	q_declare_metatype(qstandarditemmodel*)

After that, you can use Qvariant::fromvalue to store data and use Qvariant::value to get the data.

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return Qvariant::fromvalue ( model_) //.... qstandarditemmodel* Model = some_value< Span class= "Crayon-sy". value (

Using Qvariant and Qt::itemdatarole, which identifies the data types in your project, makes it easy to store arbitrary data in a predefined model provided by QT.

For example, use different role in the same qstandarditem to store multiple data.

Custom Data Roles

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enum customitemrole { levelmodelrole = Qt::userrole + + , timemodelrole = Qt::userrole + 1010, filemodelrole = Qt::userrole + 1020 /c21> };

Storing data for a specific role

123	type_of_level_item-setData(qvariant::fromvalue(level_list_model) ,levelmodelrole);

Get data for a specific role

123	qvariant data = Item, Data(Qt::levelmodelrole);

Because Qstandarditemmodel creates tree structures in behavioral units, for more complex tree structures, you can use a custom datarole to store data.

Qvariant Saving pointer data