Results 1 to 9 of 9

Thread: Tree model implementation for C++ data to QML

Threaded View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Jan 2021

    Default Tree model implementation for C++ data to QML

    I have been going through this example and was looking for another shove in the right direction if possible The example is o-so-close to being exactly what I need but the different derived types instead of all being an Item* is messing me up a bit.

    I have a datastructure on the C++ side that I will be modifying and updating (from the C++ side as well mostly). I plan on using this as the model for my views on the QML side. I don't necessarily need to use a listview or anything that will specifically need the data formatted in a certain way, but I do need access to all of this data on the QML side.

    Qt Code:
    1. class Person{
    2. QString name;
    3. QString age;
    4. }
    6. class Group{
    7. QString nickname;
    8. QString location;
    9. QList<Person> people;
    10. }
    12. class Classroom{
    13. QList<Group> groups;
    14. }
    To copy to clipboard, switch view to plain text mode 

    In use in the backend:

    Qt Code:
    1. QScopedPointer<Classroom> model(new Classroom);
    2. qmlRegisterSingletonInstance("Classroom", 1, 0, "Classroom", model.get());
    To copy to clipboard, switch view to plain text mode 

    1. So far, I have started down the route of making the Classroom derive from QAbstractItemModel (can this be a list model since there is only 1 column?)
    2. I have made group and person, QObjects, and then store pointers to them inside the relevant parent classes. Should the middle item, "Group" derive from a QAbstractItemModel as well or does the top level "Classroom" as a model cover this layer/level and the layer below..
    3. Should I use QVariantList instead and write my own notify signals, this doesn't seem right but I can wrap my head around it a bit better, so I am trying to go the right performant/model route
    4. I do not plan on writing to this model from the qml side, I might fire off a few signals that "impact" the model from the c++ side, which will then in turn cause a change in the view
    5. Should I skip the model, and just make them all qobjects with properties of all of the child items (including qlist<Qobject*>) to get what I want from the top level item, an instance of Classroom?
    6. Roles are really just to make navigation easier from the qml side, right?

    Sorry for all of the questions, I have just been running in circles a bit here and am looking for a bit of guidance.

    The below threads (along with many others) are getting me there but I wanted to take a stab at getting a push in the right direction for my own use case
    Last edited by xconverge; 23rd January 2021 at 22:43.

Similar Threads

  1. Replies: 3
    Last Post: 17th January 2016, 18:06
  2. Replies: 3
    Last Post: 16th November 2015, 21:22
  3. How to map tree model data to list view
    By msopanen in forum Qt Programming
    Replies: 0
    Last Post: 10th November 2009, 19:56
  4. Replies: 1
    Last Post: 7th July 2009, 07:13
  5. data, model and tree view
    By larry104 in forum Qt Programming
    Replies: 17
    Last Post: 3rd July 2006, 14:43


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Digia, Qt and their respective logos are trademarks of Digia Plc in Finland and/or other countries worldwide.