Important: Please read the Qt Code of Conduct -

Creating Qt Quick controls from C++

  • I'm part of a team that is looking at migrating an existing Windows C++ app to Qt. The first decision is whether to use Widgets or Qt Quick. Since Qt Quick is newer, shinier, faster, etc, that seems like the obvious choice. However, for reasons that I won't go into here, the vast majority of forms in our app are built dynamically in code. This kind of approach seems easy enough with Widgets, but looks like it could be difficult, or even infeasible, with Qt Quick. That's because the preferred way of creating Qt Quick layouts is using QML, and while there is an object model backing that, my impression is that this object model is not designed to support heavy-duty creation and manipulation of layout elements. For example, while QQuickItem is documented, none of its derived classes are, and I believe their interfaces may be private - so the only way to manipulate items is using a generic "setProperty" syntax. And while there are a few articles around that talk about accessing the Qt Quick model from C++, such as this one, they tend to use snippets of QML to get the job done in a rather hacky way, and make various comments about the perils and pitfalls of trying to manipulate the model from code.

    I can't help comparing this with two other popular layout frameworks: WPF/XAML, and Android/AXML. In both of these worlds, the markup language and the "code-behind" class hierarchy of UI elements are absolutely equivalent 1st class citizens. Anything you can do in XAML, you can also do in the C# code-behind, whether it be creating controls, changing their properties, altering layouts, etc. Likewise in Android/AXML, I can (if I choose) create FrameLayouts, RelativeLayouts, TextViews, etc in code, and arrange them and manipulate them any way I like, as an alternative to creating an AXML designer layout.

    It seems very unfortunate that Qt Quick doesn't take this approach, and that the "code-behind" experience is so limited.

    Am I missing something here? Assuming I'm not, are there any plans to make the Qt Quick class model more "open", with full documentation and public interfaces for all relevant properties and methods?

  • Hi, welcome to the forum! I totally agree with what you said. Maybe you want to bring this up to the mailing list as this forum is mostly for users and the mailing list is where the developers are.

  • @Wieland Thanks for your advice! I've posted this to the mailing list.

Log in to reply