S60 Open to new features

In my last post I began discussing the challenges that the Carbide.c++ UI designer team faced in deciding how to present the control collection to the developer in a way that would make sense to experienced UIQ developers but that would not burden novice developers with too much detail. Specifically, I talked about how we needed to separate the shared layout-agnostic control data from the layout-specific data while still maintaining a unity between them so they could be edited as one and in the most obvious place.

I mentioned that we created two different kinds of control types, and linked them together with a property in the layout control object that referenced its shared control collection control object. However, we did not want to burden the developer with having to think about these as two separate objects in the designer, so we made some enhancements to the framework to facilitate that design goal.

Here is a screenshot of the outline view showing a multipage view with one layout. The layout has one page and its container contains a label control. The layout-specific control is the one in the container. It represents in the outline the control that is visible in the layout part of the main editor. The label control with the shared data is the one in the control collection and it is only visible in the outline. To make obvious that the layout control references the control in the control collection, we use a default naming convention that initially names the layout control using the string "ref" but we can't rely on the initial name to show how these are linked together because the user is free to change these names.

Instead, we added an enhancement to the UI designer component system that we called "reference property promotion." Using this facility, a layout control component can promote the properties of its referenced control in the control collection. This means that the referenced control's properties will be editable as if they are the layout control's own properties. So although the layout control only declares layout-specific properties (plus the reference property - "control" - that points to the control collection control with the shared data), the properties of the referenced control are editable as if they belonged directly to the the layout control. This way, the user would not need to hunt down the node in the outline to edit those properties. Here is what the properties view shows when focused on the layout control (label1Ref1). The layout-specific data is editable alongside the shared data. As you can see, the layout-specific properties represent a very small portion of the data available to be edited. Without the promotion, most of these properties would only be available if the user had selected the control in the control collection in the outline.

So reference property promotion was the enhancement we added to make the shared data easily accessible. In my next post I will discuss several enhancements we added to the UI designer framework to make the creation and linking of the layout and control collection controls transparent to the user, as well as making the sharing of control collection controls among multiple layouts as easy as creating new controls.