On Wed, 02 Oct 2013 14:53:54 +0200 André Somers <an...@familiesomers.nl> wrote:
> Hi, > > Op 2-10-2013 14:34, h schreef: > > Hi, > > I have a QT project I am developing on OpenSUSE 12.3, using QT 5.1 > > (64 bit) > > I am using the QT Model /View, currently using table views. > > > > My raw data in my model (subclass of QAbstractTableModel) is a > > linked list of pointers. Each item in the list maps to a row in the > > view and there are a fixed number of columns. The view supports > > editing. > > > > Currently I have a QSortFilterProxyModel which I use to both filter > > and sort the data in the views. > > > > This is all functioning well. > > > > > > I want to introduce a new table view where the number of rows and > > columns is related to groups of data, not to individual values in my > > linked list. > > > > The basic class structure will look like this: > > > > myQAbstractTableModel > > | > > myQSortFilterProxyModel > > ________|____________ > > | | > > myView1 myView2 > > > > > > where the 2 different views have different ways of calculating the > > number of rows, number of columns and the data in them. > > > > Currently myQAbstractTableModel calculates the number of rows and > > columns and data for myView1, but not for myView2. > > > > To calculate the number of columns in myView2 I need more > > information than the result of > > myQSortFilterProxyModel::filterAcceptsRow (yes, the number of > > columns in the view is dependant on the result from which data > > items are being displayed. Am I correct in assuming that the row > > in this function refers to a "row" or tuple of data in the model, > > not a row in the final view? > > > > To be able to calculate the data to display (and edit) and the > > numbers of rows and columns I think I need to override the int > > myQAbstractTableModel::columnCount( const QModelIndex & parent ) etc > > functions in myQSortFilterProxyModel so that I know what data has > > been filtered out. I also need to know what type of view the data > > is being supplied to. > > > > An alternative would be for me to subclass myQSortFilterProxyModel > > once for each view type. This way at least I do not need to know > > which view type is requesting the data. > I think this is the *only* way to go. There is no way you can know > the caller of functions in your (proxy) model, so you do not know > which view is asking for the information. If you need different > representations of the data, or different subsets, use different > proxy models. > > Note that there is a bit of headache involved with synchronizing > selections if you need that. You can't just use the same selection > model on the two views, as they have a different (proxy) model set as > their model. There is a class in KDE that can help you deal with this > though. > > > Either way, because I need to calculate using several fields in the > > raw data I think I ant to hold a list of pointers, similar to the > > one in myQAbstractTableModel, but with the filter applied. With > > this list, I want some way of ensuring that when data is added or > > removed from myQAbstractTableModel, or the filter is changed that I > > can update the pointer list in this derived class. > > > > Does this make sense? > Not much. I think you should expose the information you need for your > views in your (base) table model. I would not expose the raw data, > though it can make sense to expose some special struct or perhaps an > iterator-like class that contains multiple bits of information at one > go if you need more than one field from the base model at the same > time for your calculations. Otherwise, you'll end up doing the lookup > for your calculations multiple times because you need to request the > data role-by-role. > > If you stick with using data from the base model in your proxies, you > will not have synchronization issues. Your base model will signal > dataChanged() (if it is implemented well) if you change a bit of > data. Your proxies will/should use that to signal their clients that > data has changed, if needed. > > André > Thankyou. I will need to put some thought into this... H _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
