General and Desktop

An update on this from my side: My initial approach wasn't flawless, as @VRonin pointed out, because QAbstractItemModel::columnCount didn't return the appropriate values. I've fixed this, by not immediately passing the new count after inserting the elements to a list, of which the size was used, but instead have the model save exactly how many categories it currently accounts for, so the connection looks like this: connect(item_registry.get(), &item_registry::category_added, [this](int position, QSharedPointer<category>) { beginInsertColumns(QModelIndex{}, position, position); _current_category_count++; endInsertColumns(); }); and likewise columnCount: int item_model::columnCount(QModelIndex const&) const { if(!_register) { qCritical() << "Item-model didn't have a register"; return 0; } return 1 /* name */ + _current_category_count; }

I'll try to give as much concise information as I can: The data is (almost always) generated by the user - an exception to this would be a shipped demo project, and in the future perhaps plugins. Children only ever have one parent, but parents can have multiple children. So it's a true 1:n relationship. The user can create parents, and assign children to them, as well as delete and reorder them. Both parents and children are part of a project's state, which is persisted through multiple iterations using messagepack. You can load a project at any time, which would completely switch out the data the program is currently using - similar to how you'd be able to with word/pretty much any IDE. Can't think of anything else that could be relevant - thanks for taking the time btw!

@jsulm Hello! Sorry, but that doesn't work. I tried to insert a loop in different places, but the result remains the same. I also tried to display the main widget. [image: 28c1a758-71f9-4787-b168-f698dfe99275.png] @SGaist Hello. So the VideoWindow.h file (VideoWindow class) is my custom widget. This is the first piece of code that I presented.

What I was suggesting is to have one QGLWidget per QGraphicsView you want to accelerate.

The complete widget code would be nice to recreate the situation locally.

Why would the parent lose a focus it didn't have in the first place ? In any case, with your additional explanations, I understand better what you want which makes it way less "surprising". Are all your controls grouped in group boxes ?

Hi, Why do you need to put them out of the stacked widget ? Implement them so that you can refresh/reset them so you only have one instance of each and be done with it.

After some heavy detective work, I found the cause to my problem. Cute Qt was free of guilt as expected, and this problem is very specific to our app. But I am leaving here a description of the resolution just in case somebody else ever hits something similar. Our software makes use of Intel's Embree. And there is a pair of rtcNewDevice/rtcReleaseDevice calls to init and dispose of resources used by said library. We use Embree to build some raytracing structures that are indeed dependent on document size (number of objects/primitives). For some reason, starting at some (consistently the same) high number of objects, COM is affected badly within this sandwich of New/Release calls. The effect is that services such as Drag & Drop and very specially the native file Open/Save dialogs (wrapped by QFileDialog) are left inoperable. In the very case of our app, creating and disposing of the Embree device only when it is about to be used, instead of once per document was enough to fix my problem. I haven't found anything online about this. But our particular problem is gone now. Thank you for your replies!

@bemlun Hi Your syntax indicates you are using an resource file ( the ":/" ) However, the project seems not to contain one. please see here https://doc.qt.io/qtforpython/overviews/resources.html I normally recommend using a resource file for icons. But since its python im not sure it has the same benefits :)

@Diren said in QUdpSocket.readyread is not emitting when QCoreApplication not created from main thread.: it works. time to mark your post as solved then? thanks.

@Ashutosh_Sachdeva Assuming you mean you have changed over to QStackedWidget, isn't it nicer/cleaner than all those show/hides yourself? And it makes code easier to follow. :)

@LeLev https://doc.qt.io/qt-5/qstring.html#arg is the overload you want for strings, use fieldWidth argument (negative number if you want left-aligned as per your example). Tabs are quick and work till they don't (depends on number of characters determining where the next tab stop is).

Also make sure you are compiling with the /clr option on

Thank you very much, I managed to finally do it.

@kitfox Putting the path in quotes is usually enough. But the best advice I can give you: avoid spaces at all. Rename the directories to have proper ASCII names without spaces will save you a lot of trouble. Also blame the library vendor so he becomes aware of the problem. Regards

@Ucn_ Don't you have send as class member? Regarding error: simply remove & in front of send in connect as send is now already a pointer. QObject::connect(send, SIGNAL(valueChanged()), SLOT(someFunction()));