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Видео на тему: channel43999792

In the previous episode, we implemented a proxy model for reversing rows but left out one last signal to react to, namely layoutAboutToBeChanged. Reacting to that signal is rather difficult, which is why we have dedicated a complete episode for that. It will, among other things, take us through a discussion on persistent model indexes. 0:00 Introduction 1:11 Understanding QModelIndex 2:57 Updating the persistent model indexes 3:46 signal layoutAboutToBeChanged 5:58 signal layoutChanged 8:00 Why not for rowsInserted, etc. 9:50 Let me show you where persistent indexes get updated for rowsInserted The example code showcased in this video is available here: https://github.com/KDABLabs/kdabtv/tree/master/Qt-Widgets-and-more/ReverseRowsProxyModelThe example code showcased in this video is available here: https://github.com/KDAB/kdabtv All Qt - QML Tutorial videos: https://rutube.ru/plst/557554All Qt Container in Qt 5 and Qt 6 videos: https://rutube.ru/plst/618679One of the most complex things in Qt's model/view framework is the implementation of proxy models. In this episode, I'll show an almost complete implementation of a proxy model which reverses its rows but, at the same time, also gives hints for where and when you can cut corners. 0:00 Introduction 2:06 Implementing the QAbstractProxyModel API 9:00 Running the code without listening to signals 12:13 It is OK to not go further than this! 14:17 emitting beginResetModel and endResetModel is sometimes enough 16:38 listening to dataChanged signal 19:01 rowsAboutToBeInserted, rowsInserted, ... signals 22:14 headerDataChanged, modelReset, modelAboutToBeReset signals 23:08 Unit testing the model 27:26 The MasteSpy class - why is it needed 29:31 The MasterSpy class - how is it used 31:19 Careful proxy models may crash! The example code showcased in this video is available here: https://github.com/KDABLabs/kdabtv/tree/master/Qt-Widgets-and-more/ReverseRowsProxyModelWhether you've just finished watching our 54 "Introduction to Qt/QML" videos or you are just looking for QML tips and tricks, here are 35 more videos that can help you save time and increase your productivity. So check out our Qt Creator tips, our git tips, and much more! All Introduction to Qt / QML videos: https://rutube.ru/plst/557554 All QML tips and tricks videos : https://rutube.ru/plst/618704