what is the signal for qtreeview changed
what is the signal for qtreeview changed
There is a dictionary taken from JSON file, that is represented by QTreeView QStandardItemModel.
QTreeView
QStandardItemModel
A user can reorganize QTreeView(add, delete, drag-n-drop) and rename items.
QTreeView
The goal is: call function that reads changed QTreeView, makes the dictionary and writes it to initial JSON file.
QTreeView
I can do it by pressing a QPushButton after changes occurred or by binding that function to every change e.g. call function when an item is deleted, call function when an item is added, call a function when an item is renamed and so on.
QPushButton
Is there any way to call a function if any of changes occur? Is there such a signal that corresponds to all of the mentioned changes?
QAbstractItemModel::dataChanged()
QAbstractItemModel::layoutChanged()
A
QTreeView is a view, so it's a widget. Widgets normally don't signal their updates, instead they are delivered an event when they should update. Did you mean that you wish to know when the model has changed? If so, you should read the documentation: see introduction to model view programming.– Kuba Ober
Jun 22 '15 at 13:49
QTreeView
2 Answers
2
The rowsMoved and itemChanged signals do what you think they do. See http://doc.qt.io/qt-4.8/qstandarditemmodel.html
rowsMoved
itemChanged
I'm looking for the way avoiding bindings function to each one change. Is there any signal for all of changes.
– Sergii Artele
Jun 22 '15 at 13:23
@SergiiArtele How do you know that there are "all" changes - i.e. why do you presume that there is more than one change? Alternatively, if you think that "binding" a function to each kind of change is to be avoided: well, it can't be, since there is no signal that just says "hey, something changed". There are different kinds of changes: structural and non-structural, and it differs quite a bit how you might handle them. Perhaps tell us what you need to do with such changes first.
– Kuba Ober
Jun 22 '15 at 13:50
Ok, I meant to use such a signal that covers any of changes I do. Like
selectionChanged may be used to cover wheither item was clicked or selected by arrows on the keyboard or keyboardSearch.– Sergii Artele
Jun 23 '15 at 9:49
selectionChanged
keyboardSearch
As @vahancho suggests in the comments, you should connect to the layoutChanged signal. All models should emit this immedaitely after making any changes which could affect the view. So this will include sorting and filtering, as well as re-ordering, editing, deleting, etc.
The dataChanged signal is similar, but only really useful if you want to monitor specific items.
layoutChanged works in my case only for drag'n'drop. It doesn't work when I add, delete or rename item.So I will use
itemChanged when renaming occures and I will call function that reads tree and saves its content to JSON file when delete or add– Sergii Artele
Jun 23 '15 at 9:42
itemChanged
@SergiiArtele. Sorry - it seems I've never fully tested what these signals do, and so I was mislead by the Qt docs.
– ekhumoro
Jun 23 '15 at 15:49
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QAbstractItemModel::dataChanged()and/orQAbstractItemModel::layoutChanged()signals might help.– vahancho
Jun 22 '15 at 13:18