View using multiple models

[johnmauer]

I am building a custom view to duplicate the attached graphic. The user can change the data used for the histogram, and the parameters of the curve in other views, so the views need to be synced. I had hoped to subclass the QAbstractItemView class to take advantage of the automatic notification, but that appears to need the notifications to be funneled through one model. If I built my own view, but kept the models, then I would need to implement the same connections. And I am unsure of all the connections between the model and the view.

Please note that, although I have simplified this graphic to just one mathematical curve, the plot could have a dozen such curves. And all of them can be updated by the users elsewhere.

[wysota]

Ok, you have basically two choices. Either implement a proxy model where you use custom roles (Qt::UserRole and up) to return data from the "second" model or make a proxy where your curves will become additional columns in the proxy model (compared to the source model). From what I see you main model has only one column, so curves can occupy subsequent ones.

One way or the other you will end up with a single model where two source models are represented either by different roles or by different columns.

[johnmauer]

The approach using different columns is excellent; I had forgotten about the extra column parameter. Thanks a lot.

[QtQuery]

Good day. Could you tell me how to add extra columns to the proxy model, mentioned above? I tried insertColumn() in my QSortFilterProxyModel subclass but it didn't work (returned false).
Or is it a matter of overriding columnCount() and data() to return the data from the second model in a new column?
Thanks in advance.

[wysota]

Or is it a matter of overriding columnCount() and data() to return the data from the second model in a new column?

Yes, that's correct - you need to reimplement at least columnCount(), index(), parent() and data() to take extra columns into account.

[NoRulez]

Hello,

i've the same problem, i need to merge 2 tree models into one treeview.
The first model is a simple QStandardItemModel. The second model is a QDirModel.
Now i want to display both models into one treeview. So from the posting i think i need an overlay...

CustomModel Items
     Custom Item 1 (QStandardItemModel)
          Custom SubItem 1 (QStandardItemModel)
          Custom SubItem 2 (QStandardItemModel)
     Custom Item 2 (QStandardItemModel)
          Custom SubItem 1 (QStandardItemModel)
          Custom SubItem 2 (QStandardItemModel)
DirModel Items
     C: (QDirModel)
          Qt (QDirModel)
               2010.05 (QDirModel)

CustomModel Items
     Custom Item 1 (QStandardItemModel)
          Custom SubItem 1 (QStandardItemModel)
          Custom SubItem 2 (QStandardItemModel)
     Custom Item 2 (QStandardItemModel)
          Custom SubItem 1 (QStandardItemModel)
          Custom SubItem 2 (QStandardItemModel)
DirModel Items
     C: (QDirModel)
          Qt (QDirModel)
               2010.05 (QDirModel)

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So, i think i need two functions setCustomModel(QAbstractItemModel *pModel); and a function setDirModel(QAbstractItemModel *pModel); for example.
But how can i handle it that when i click on an item in the QDirModel to display a file content and if i click on an item in the QStandardItemModel to display for example the a string? To simplify this, i want to know how the treeview knows which model must be accessed.

I've also attached a screenshot of the current situation. In the left (empty) TreeView i will merge the right ones.

Thanks in advance

Best Regards
NoRulez