我正试图通过使用 qmlRegisterSingletonType
但当我试图访问QML中的对象时,我在控制台日志中得到以下错误。
qrc:/qml/MyQml.qml:21 Element is not creatable.
以下是我的代码。
/ TestSingletonType.h Class
#include <QObject>
#include <QJsonObject>
#include <QVariantMap>
#include <QQmlEngine>
class TestSingletonType : public QObject
{
Q_OBJECT
Q_DISABLE_COPY(TestSingletonType)
TestSingletonType(QObject *parent = nullptr) {}
public:
// To maintain single object of the class
static QObject *qmlInstance(QQmlEngine *engine, QJSEngine *scriptEngine)
{
Q_UNUSED(engine);
Q_UNUSED(scriptEngine);
if (theInstance == NULL)
theInstance = new TestSingletonType();
return theInstance;
}
private:
static QObject *theInstance; // I have set it to NULL in Cpp file
};
/ Main.cpp
int main(int argc, char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
qmlRegisterSingletonType<TestSingletonType>("com.my.TestSingletonType", 1, 0, "TestSingletonType", &TestSingletonType::qmlInstance);
// Rest of the code to load the QML
return app.exec();
}
/ MyQml.qml文件。
import QtQuick 2.0
import QtQuick.Controls 2.0
import com.my.TestSingletonType 1.0
Item {
TestSingletonType { <---- Getting error on this line
id: mySingleClass
}
// Rest of my code which uses "mySingleClass"
}
如果我使用 qmlRegisterType
那么它就能正常工作,但不是用 qmlRegisterSingletonType
.
我参考了下面的答案和链接。如何为qmlRegisterSingletonType实现一个单人提供者? https:/doc.qt.ioqt-5qqmlengine.html#qmlRegisterSingletonType。
这个错误很明显:在QML中并没有创建一个单体,因为它已经在回调中创建了(qmlInstance方法),你只需要访问该方法的属性。typeName("TestSingletonType")是id。
Item {
// binding property
foo_property : TestSingletonType.foo_value
// update singleton property
onAnotherPropertyChanged: TestSingletonType.another_prop = anotherProperty
}
// listen singleton signal
Connections{
target: TestSingletonType
onBarChanged: bar_object.bar_property = bar
}