如何从C ++调用QML对象的方法

Question

I have following QML code:

Rectangle {
id: mainRect
...
    Rectangle{
    id: listRect
    ...
       ListModel {
          id: idModel
          ... some stuff added
       }
    }
}

And I want to clear idModel, using clear method of ListModel. Stuff like this (inside QML) works perfectly:

 idModel.clear()

But I want to achieve same in C++. Tried following:

  QQuickView view;
  view.setSource(QUrl("qrc:/main.qml"));
  QQuickItem* item = view.rootObject();
  QObject* model = item->findChild<QObject*>("mainRect")->findChild<QObject*>("listRect")->findChild<QObject*>("idModel");
  QMetaObject::invokeMethod(model,"clear");

also tried to search model as

 QObject* model = item->findChild<QObject*>("idModel");
 QObject* model = item->findChild<QObject*>("listRect")->findChild<QObject*>("idModel");

But this stuff above not working... I can't even understand - if nothing is found by findChild method in C++, or InvokeMethod is not working.

Could anyone explain this to me? Using QT5.4 \\ QtQuick 2.4

Answer 1

To use findChild() you should set objectName to your qml item.

Rectangle {
id: mainRect
...
    Rectangle{
    id: listRect
    ...
       ListModel {
          id: idModel
          objectName: "idModel"
          ... some stuff added
       }
    }
}

Then, you can get pointer to your ListModel

QObject* model = item->findChild<QObject*>("idModel");

To invoke method, you should use QMetaObject::invokeMethod()

QMetaObject::invokeMethod(model,"clear");