On 8/23/12 5:04 AM, André Somers wrote: > So, you *do* have a table model, but you are just displaying it in a > QTreeView? That's very possible, of course. Note that QTableView can be > given the same appearance as QTreeView, but is more efficient at > layouting because it does not need to deal with the (complex) tree > aspects of it.
I choose QTreeView mainly for its look and row-base selection. Our existing app on Mac uses Data Browser control (think Finder) and QTreeView provides the closest look and feel to it. > Please keep in mind that *any* model can in principle be viewed in *any* > view. You may loose certain aspects of the data of not use all features > of the view, but normally, it will work. That's because views only rely > on the common interface provided by QAbstractItemModel. Yes, I understand I can use basically any view with and model. And I really appreciate that feature/function. Makes my prototyping a lot easier. > For efficient updating, you will need to keep track of changes: inserts, > deletes and updates of items. Just rebuilding will generally not be very > efficient. That's what I did in the existing app. > No, resetting is not the way. It will result in loosing selection, > scroll position and is generally visually disturbing for the user. As > others have notices, the beginInsertRows, beginRemoveRows and their > respective end* functions are your tools, together with emitting the > dataChanged signal for updates to data. Thanks to everybody pointing this out. I will give it a try. The issue I have is actually being coming from OS X Data Browser control. It tracks items by user supplied 32-bit IDs instead of indices. That makes updating the list a lot easier by just adding new IDs and removing old one without worrying about the indices change after each insert/remove. And also makes batch operations much more straightforward and efficient. With Qt, I think, I have to add/remove ID and index pair together, one pair at a time, to keep the ID-to-index in sync. I probably can batch insert new ID-index pairs at the end of my list. But since IDs to be removed can be scattered in the list, it will be hard to remove them in batches. > However, it also depends on the size of your dataset. Are you talking 10 > rows, 1k, 1M or even more? It can be from Ks to 100s of Ks. But I am in the process to redesign it so we'll never deal with more than 10s of Ks. _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
