C++ Qt Quick2为Singleton类类型创建qmlRegisterSingletonType
我试图使用C++ Qt Quick2为Singleton类类型创建qmlRegisterSingletonType,c++,qt,qml,singleton,qtquick2,C++,Qt,Qml,Singleton,Qtquick2,我试图使用qmlRegisterSingletonType创建singleton属性,但当我尝试访问QML中的对象时,控制台日志中出现以下错误: qrc:/qml/MyQml.qml:21 Element is not creatable. 下面是我的代码: //TestSingletonType.h类 #include <QObject> #include <QJsonObject> #include <QVariantMap> #include <
qmlRegisterSingletonType
创建singleton属性,但当我尝试访问QML中的对象时,控制台日志中出现以下错误:
qrc:/qml/MyQml.qml:21 Element is not creatable.
下面是我的代码:
//TestSingletonType.h类
#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
};
#包括
#包括
#包括
#包括
类TestSingletonType:公共QObject
{
Q_对象
Q_禁用_复制(TestSingletonType)
TestSingletonType(QObject*parent=nullptr){}
公众:
//维护类的单个对象
静态QObject*qmlInstance(QQmlEngine*engine、QJSEngine*scriptEngine)
{
Q_未使用(发动机);
Q_未使用(脚本引擎);
if(instance==NULL)
instance=newtestsingletontype();
返回指令;
}
私人:
静态QObject*theInstance;//我已在Cpp文件中将其设置为NULL
};
//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();
}
intmain(intargc,char*argv[])
{
QCoreApplication::setAttribute(Qt::AA_enableHighdDiscaling);
QGUI应用程序应用程序(argc、argv);
qqmlaplicationengine;
qmlRegisterSingletonType(“com.my.TestSingletonType”、1、0、“TestSingletonType”、&TestSingletonType::qmlInstance);
//用于加载QML的其余代码
返回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"
}
导入QtQuick 2.0
导入QtQuick.Controls 2.0
导入com.my.TestSingletonType 1.0
项目{
TestSingletonType{错误很明显:没有在QML中创建singleton,因为它已经在回调(QMLinInstance方法)中创建,您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
}