在QML文件之间共享对象 [英] Share an object between QML files

问题描述

我是QML编码的新手，我正在尝试编写我的第一个Sailfish OS应用程序。对于后端，我创建了一个C ++类。但是，我想实例化该C ++类的一个对象，并在Cover和主页（两个单独的QML文件）中使用它，因此我可以使用存储在该类中的相同数据。如何在单独的QML文件中处理同一对象？

I'm new to coding in QML and I'm trying to write my first Sailfish OS app. For the backend I have created one C++ class. However, I want to instantiate one object of that C++ class and use it both in the Cover and the main Page (two separate QML files), so I can work with the same data, stored in that class. How do address that same object in the separate QML files?

推荐答案

您可以在QtQuick上下文中使该对象可用：

You can make the object available in the QtQuick context:

class MySharedObject : public QObject {
    Q_OBJECT
public:
    MySharedObject(QObject * p = 0) : QObject(p) {}
public slots:
    QString mySharedSlot() { return "blablabla"; }
};

main.cpp

MySharedObject obj;    
view.rootContext()->setContextProperty("sharedObject", &obj);

以及在QML中的任何地方：

and from anywhere in QML:

console.log(sharedObject.mySharedSlot())

如果不想在QML中将其全局化，可以封装一下，只需创建另一个 QObject 派生类，将其注册以在QML中实例化，其中有一个属性，该属性返回指向该对象实例的指针，这样，它仅在实例化访问器 QML对象的地方可用。

If you don't want to have it "global" in QML, you can go about a little to encapsulate it, just create another QObject derived class, register it to instantiate in QML and have a property in it that returns a pointer to that object instance, this way it will be available only where you instantiate the "accessor" QML object.

class SharedObjAccessor : public QObject {
    Q_OBJECT
    Q_PROPERTY(MySharedObject * sharedObject READ sharedObject)

public:
    SharedObjAccessor(QObject * p = 0) : QObject(p) {}
    MySharedObject * sharedObject() { return _obj; }
    static void setSharedObject(MySharedObject * obj) { _obj = obj; }
private:
    static MySharedObject * _obj; // remember to init in the cpp file
};

main.cpp

MySharedObject obj;
qRegisterMetaType<MySharedObject*>();

SharedObjAccessor::setSharedObject(&obj);
qmlRegisterType<SharedObjAccessor>("Test", 1, 0, "SharedObjAccessor");

和在QML中

import Test 1.0
...
SharedObjAccessor {
        id: acc
}
...
console.log(acc.sharedObject.mySharedSlot())

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