Delete a child of a QQuickItem

maxwell31

Hi,

I created a Plot class derived from QQuickItem which displays x vs y plot curves. For the single plot curves I created a PlotCurve class which is also derived from QQuickItem and the plot curves are childs of the Plot object. The Plot object has a vector of pointers to its childs.

I am wondering how I can reset my Plot Object to its original state. Simply calling delete or deleteLater on the adresses of the plot curves is not working.

If it was c++ only I would probably delete the whole plot object, and create a new one. But as I instantiate the plot object in qml this is not an option.

How can I reset my object (remove its childs)?

dheerendra

Not quite clear about the question completed. If you want to delete the child object at QML, if you have identity property of QML object, you can say <id>.destroy() or iterate through the child objects using children property of an item and destroy them.

maxwell31

Sorry for the unclear question. How would I destroy it from c++? In c++ I got the object vis

     QObject *qmlplotobject = rootObjects.value(0)->findChild<QObject*>("myPlot");

This object has a member QVector<PlotCurve *> _curves, but deleting the curves via

   for(int i=0;i<_curves.size();i++) {
      delete _curves[i];
   }

does not work. The plot curves were created via an add_curve function which calls the creator of PlotCurve (derived vom QQuickItem) which also sets the parent of the PlotCurve to be the Plot object.

Is there something like a remove children function?

maxwell31

Hm,

I tried to call removeAllChildren in the updatePaintNode function of Plot but it seems that it has no effect

maxwell31

Here my stackoverflow post, where I tried to improve the question: https://stackoverflow.com/questions/50852203/qtquickscene-graph-delete-child-node

maxwell31

this is what i was looking for:

  for(auto &curve : _curves) {
      curve->setParent(nullptr);
      curve->setParentItem(nullptr);
      curve->deleteLater();
   }