Custom view - problems with selection



  • Hi

    I've a custom view which is meant to be used with list-like models (one column, n-rows).
    My view displays items horizontaly, but wraps when right edge is reached. Here is an example:

    Consider model with 10 items (one item per row in 1 column).
    My view would display them like that:

    +---------------------------------+
    | Item1   Item2   Item3   Item4   |
    | Item5   Item6   Item7   Item8   |
    | Item9   Item10                  |
    |                                 |
    +---------------------------------+
    

    I hope it is clear. The problem I have is selection. I wish I could have the bahavior like that: when user clicks Item2 and then clicks Item6 with shift, items 2, 3, 4, 5 and 6 should be selected. However Qt framework calls setSelection() in my view with a rect which covers Item2 and Item6. In a general case I'm unable to figure out which items should I pass to selection model to get my desired behavior. I went through QAbstractItemView's doc and I cannot see anything that could help me. Any ideas or suggestions?


  • Lifetime Qt Champion

    Hi,

    What widget are you using for that ?



  • I've a custom class for this view derived directly from QAbstractItemView.


  • Lifetime Qt Champion

    Then it would likely be nice to share the code you are using for the view.



  • @SGaist
    here you go: images tree view. In line 249 (const std::deque<QModelIndex> linear_selection = convertToLinearSelection(items);) I was trying to convert rect into something that suits me, but it is working only under certain circumstances.

    However I think that code is irrelevant here. I just have very untypical view which arranges items in different way they are stored in model. Qt framework sends me selection as a rect which doesn't allow me to select items the way I want.


  • Lifetime Qt Champion

    Did you already saw the using a selection model part of the Model View Programming chapter ?
    There's also the Model View tutorial that could be of interest.



  • @SGaist Thank you for your interest however I'm afraid we do not understand each other.
    I'll deal with my problem by overriding QWidget::mousePressEvent and doing my own clicks interpretation there to generate proper selection.

    If you would like to see visualtion of my problem you can compile http://doc.qt.io/qt-5/qtwidgets-itemviews-chart-example.html example which also suffers from the same problem as I do.
    Select with rectangle any two consecutive elements and only these two will get selected.
    One exception from this rule: select biggest blue item and the green one above it. Whole chart will be selected. This is because Qt framework sends selection as a rect which covers first and last item and in my case I'm unable to figure out which two items were actualy selected.

    Regards.


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