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Thread: How to disable & enable a row in QTreeView

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    Question How to disable & enable a row in QTreeView

    Hi, I have a QTreeView with custom model derived from QAbstractItemModel. I want to disable the parent item until all of its child items gets populated. Once done, then I have to enable the parent item. How can I achieve this using flags() function?

    I want this kind of behavior for all the tree nodes to avoid user click till it is fully loaded.

    Please help on this

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    Default Re: How to disable & enable a row in QTreeView

    Qt Code:
    1. setFlags( index, flags( index ) ~ Qt::ItemIsEnabled ); // disables the item at index
    2. setFlags( index, flags( index ) | Qt::ItemIsEnabled ); // enables the item at index
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    Should do it. Call the first one before you populate, call the second one after population is finished. You should probably call setExpanded( index, false ) on the tree view first to ensure that the parent is colapsed before populating the children.
    <=== The Great Pumpkin says ===>
    Please use CODE tags when posting source code so it is more readable. Click "Go Advanced" and then the "#" icon to insert the tags. Paste your code between them.

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    Default Re: How to disable & enable a row in QTreeView

    I am not seeing any in-built setFlags() function on QModelIndex.

    auto flags = sourceIndex.flags();

    flags.setFlag(Qt::ItemIsEnabled,false);

    Don't know how to set this flag again to the sourceIndex

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    Default Re: How to disable & enable a row in QTreeView

    I am not seeing any in-built setFlags() function on QModelIndex.
    QAbstractItemModel::setFlags()
    <=== The Great Pumpkin says ===>
    Please use CODE tags when posting source code so it is more readable. Click "Go Advanced" and then the "#" icon to insert the tags. Paste your code between them.

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    Default Re: How to disable & enable a row in QTreeView

    Hi, I am not able to find any such setFlags() method under QAbstractItemModel

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    Default Re: How to disable & enable a row in QTreeView

    Sorry, sorry, my mistake. You need to implement the QAbstractItemModel::flags() method to return the correct set of flags for each item in your model. I was thinking of QTableWidgetItem, which does have a setFlags() method.

    So your tree model should initially return flags without the Qt:: ItemIsEnabled bit set for parents whose children have not been populated. Once all of the children have been loaded, then your model can enable the parent index. I think emitting the dataChanged() signal will cause the view to request the new data and flags for the parent, or possibly just hovering the mouse over the parent item will cause the flags to be queried. You'll have to test that.
    <=== The Great Pumpkin says ===>
    Please use CODE tags when posting source code so it is more readable. Click "Go Advanced" and then the "#" icon to insert the tags. Paste your code between them.

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    Default Re: How to disable & enable a row in QTreeView

    Thanks for your inputs. Will try

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