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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
//! [0]
struct MyStruct
{
int i;
...
};
Q_DECLARE_METATYPE(MyStruct)
//! [0]
//! [1]
namespace MyNamespace
{
...
}
Q_DECLARE_METATYPE(MyNamespace::MyStruct)
//! [1]
//! [2]
MyStruct s;
QVariant var;
var.setValue(s); // copy s into the variant
...
// retrieve the value
MyStruct s2 = var.value<MyStruct>();
//! [2]
//! [3]
int id = QMetaType::type("MyClass");
if (id != QMetaType::UnknownType) {
void *myClassPtr = QMetaType::create(id);
...
QMetaType::destroy(id, myClassPtr);
myClassPtr = 0;
}
//! [3]
//! [4]
qRegisterMetaType<MyClass>("MyClass");
//! [4]
//! [6]
QDataStream &operator<<(QDataStream &out, const MyClass &myObj);
QDataStream &operator>>(QDataStream &in, MyClass &myObj);
//! [6]
//! [7]
int id = qRegisterMetaType<MyStruct>();
//! [7]
//! [8]
int id = qMetaTypeId<QString>(); // id is now QMetaType::QString
id = qMetaTypeId<MyStruct>(); // compile error if MyStruct not declared
//! [8]
//! [9]
typedef QString CustomString;
qRegisterMetaType<CustomString>("CustomString");
//! [9]
//! [10]
#include <deque>
Q_DECLARE_SEQUENTIAL_CONTAINER_METATYPE(std::deque)
void someFunc()
{
std::deque<QFile*> container;
QVariant var = QVariant::fromValue(container);
// ...
}
//! [10]
//! [11]
#include <unordered_list>
Q_DECLARE_ASSOCIATIVE_CONTAINER_METATYPE(std::unordered_map)
void someFunc()
{
std::unordered_map<int, bool> container;
QVariant var = QVariant::fromValue(container);
// ...
}
//! [11]
//! [12]
QPointer<QFile> fp(new QFile);
QVariant var = QVariant::fromValue(fp);
// ...
if (var.canConvert<QObject*>()) {
QObject *sp = var.value<QObject*>();
qDebug() << sp->metaObject()->className(); // Prints 'QFile'.
}
//! [12]
//! [13]
#include <memory>
Q_DECLARE_SMART_POINTER_METATYPE(std::shared_ptr)
void someFunc()
{
auto smart_ptr = std::make_shared<QFile>();
QVariant var = QVariant::fromValue(smart_ptr);
// ...
if (var.canConvert<QObject*>()) {
QObject *sp = var.value<QObject*>();
qDebug() << sp->metaObject()->className(); // Prints 'QFile'.
}
}
//! [13]
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