在qt main.cpp中为与qml通信而强制转换rootobject（）时出错 我是QT快的新手，我尝试编写一个代码，在QML信号上调用C++插槽 //main.cpp #include "qtquick1applicationviewer.h" #include "QApplication" #include"authenticate.h" int main(int argc, char *argv[]) { QApplication app(argc, argv); QDeclarativeView view(QUrl::fromLocalFile("MyItem.qml")); QObject *item = view.rootObject(); Authenticate myClass; QObject::connect(item, SIGNAL(qmlSignal(QString)), &myClass, SLOT(cppSlot(QString))); view.show(); return app.exec(); }

错误是： main.cpp:15:错误：无法在初始化中将“QGraphicsObject*”转换为“QObject*” QObject*item=viewer.rootObject（）

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您应该显式强制转换到

QObject*

：

QObject *item = qobject_cast< QObject * >( view.rootObject() );

QObject *item = qobject_cast< QObject * >( view.rootObject() );

#include <QGraphicsObject>