Singal not working correct when filtering in QSortFilterProxyModel

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Hey,

my code looks like this:

void MainWindow::synonymItemChanged(const QModelIndex &index)
{
    const int id = mSynonymProxyModel->data(index.siblingAtColumn(Column::FungusId)).toInt();

    mFungusProxyModel->setFilterRegularExpression(idFilter(id));
    mFungusProxyModel->setFilterKeyColumn(Column::Id);

    QModelIndex fungusIndex = mFungusProxyModel->index(0,0);

    const QString redlist = mFungusProxyModel->data(fungusIndex.siblingAtColumn(Column::Assignment)).toString();

    if(redlist.isEmpty()){
        ui->redListSelection->setCurrentIndex(Index::None);
    }

    mFungusMapper->setCurrentModelIndex(fungusIndex);
}

void MainWindow::fungusItemChanged(const QModelIndex &index)
{


        const int id = mFungusProxyModel->data(index.siblingAtColumn(Column::Id)).toInt();
        const QString redlist = mFungusProxyModel->data(index.siblingAtColumn(Column::Assignment)).toString();

        if(redlist.isEmpty()){
            ui->redListSelection->setCurrentIndex(Index::None);
        }

        mSynonymProxyModel->setFilterRegularExpression(idFilter(id));
        mSynonymProxyModel->setFilterKeyColumn(Column::FungusId);

        ui->synonymList->setModel(mSynonymProxyModel);
        ui->synonymList->setModelColumn(Column::Name);

        mFungusMapper->setCurrentModelIndex(index);
}

void MainWindow::on_selection_currentIndexChanged(int index)
{
    const bool isSearchbarEmpty = ui->searchbar->text().isEmpty();
    const QString name = ui->searchbar->text();

    mSynonymProxyModel->setFilterFixedString("");

    switch (index)
    {
        /*
         * Index for Selection
         *
         * Index 0 = Vollnamen
         * Index 1 = Synonyme
         * Index 2 = Deutsche Namen
         *
         * */
        case 0:
            if(!isSearchbarEmpty)
            {
                mFungusProxyModel->setFilterRegularExpression(createRegularExpressionFilter(name));
                ui->fungusList->setModel(mFungusProxyModel);
                ui->fungusList->setModelColumn(1);

            }
            else
            {
                ui->fungusList->setModel(mFungusProxyModel);
                ui->fungusList->setModelColumn(1);
                connect(ui->fungusList->selectionModel(), &QItemSelectionModel::currentChanged, this, &MainWindow::fungusItemChanged);

            }
            break;
        case 1:
            if(!isSearchbarEmpty)            {
                mSynonymProxyModel->setFilterRegularExpression(createRegularExpressionFilter(name));
                ui->fungusList->setModel(mSynonymProxyModel);
                ui->fungusList->setModelColumn(1);

            }
            else
            {
                ui->fungusList->setModel(mSynonymProxyModel);
                ui->fungusList->setModelColumn(1);
                connect(ui->fungusList->selectionModel(), &QItemSelectionModel::currentChanged, this, &MainWindow::synonymItemChanged);


            }
            break;
        case 2:
            if(!isSearchbarEmpty)
            {
                mGermanNameProxyModel->setFilterRegularExpression(createRegularExpressionFilter(name));
                ui->fungusList->setModel(mGermanNameProxyModel);
                ui->fungusList->setModelColumn(0);
            }
            else
            {
                ui->fungusList->setModel(mGermanNameProxyModel);
                ui->fungusList->setModelColumn(0);
            }
            break;
    }
}

So what's my problem now?
If the index in the method on_selection_currentIndexChanged is set to 1, it jumps to the method synonymItemChanged. This also works so far. The strange behavior is now in the synonymItemChanged method. When it reaches the following line

mFungusProxyModel->setFilterRegularExpression(idFilter(id));

it jumps me into the method fungusItemChanged. I don't understand why unfortunately. Does anyone know and can explain this to me?

BTW: mFungunsProxyModel, mSynonymProxyModel are QSortFilerProxyModel's, mFungusMapper is a QDataWidgetMapper, fungusList is a QListView

Christian Ehrlicher

@Gabber said in Singal not working correct when filtering in QSortFilterProxyModel:

Does anyone know and can explain this to me?

Because setFilterRegularExpression() changes the current selection

? Offline

@Christian-Ehrlicher
Okay, thanks for the info. Do you have any idea how I can "work around" this or what I should change so this doesn't happen? I need the filtering...

Christian Ehrlicher

I don't see why this slot should not be called when a filter is applied.
But you can e.g. disconnect the signal during the call.

? Offline

@Christian-Ehrlicher
What I actually want to achieve: I have 3 models mFungusProxyModel, mSynonymProxyModel and mGermanNameProxyModel. mFungusProxyModel contains all data about my mushrooms, mSynonyProxyModel contains all synonyms of the mushrooms and mGermanNameProxyModel contains all German names of the mushrooms. One of the three, should be displayed in my QListView depending on which index is selected in my QComboBox. If I then press on an index/item/value, the mushroom data shall be displayed in my QLineEdits, the corresponding synonyms in a QListView and the German names also in a QLinEdit. Since the data is available in 3 different models, I have to filter them of course and as you can see I have done that using my own slots. Unfortunately, this does not work as I imagined, because it jumps back into the slot fungusItemChanged() when filtering the mFungusProxyModel.

Can you please help me how best to implement this? Best by code examples or links where I can read things. Please don't blame me, this is my first project in programming and especially with Qt.

Thanks for your help :)

SGaist

Hi,

The question is: why are you changing the mFungusProxyModel regular expression when the synonym changes ?

The synonyms shall match the currently selected fungus so it does not make sense to change the mFungusProxyModel when toying with the synonyms.

? Offline

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

The question is: why are you changing the mFungusProxyModel regular expression when the synonym changes ?

Because I have three different tables in my database that have information about a mushroom. For example, the table Mushrooms contains the id, the name, the genus, the species, the family, the order and the note. This data is then assigned to the mFungusProxyModel. The synonyms are stored in the Synonyms table, which has a 1:N relationship to the Mushroom table. Thus, the table contains the id, the synonym name and the fungusID. This data is then assigned to the mSynonymProxyModel and so on. So that I get now the data into the appropriate QLineEdit's etc., I must look for in the mFungusProxyModel.

I hope I could answer your question. If you have a better / nicer idea how I can implement the whole thing I will gladly take the tip. I also like to share my code if that helps you.

SGaist

That I understood, my question is really: why selecting a synonym should trigger an update to the fungus proxy ?

The thing is:

select a fungus
update the synonym filter

That is logic.

Then:

select a synonym
update the fungus filter

Why ? As you said, you have a set of synonym that matches one fungus. So why should it have any influence on the current fungus selection ?

? Offline

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

Then:

select a synonym
update the fungus filter

Why ?

I have to query the data that belong to the synonym and are stored in the mushroom table and I do that by filtering the ID in the mFungusProxyModel. I hope I didn't miss the answer again. I am glad about your help

Do you have any idea how I can make it better?

SGaist

That's the thing that is confusing: you already filtered the fungus model since you have the synonyms. So there's no need to filter it again. Just grab the data you want directly.

? Offline

I'm not clear where you see the mFungusProxyModel's filtering? If I select "Synonyms" in the QComboBox and then click on one, I don't have the data from the mFungusProxyModel yet, but only the data from the mSynonymProxyModel or am I missing something here?

SGaist

Wait, do you mean you may have the synonyms "unfiltered" ?

The logic as I understand it is:

Fungus is the central model
If none is selected, no synonyms shall be available
Select a fungus
Synonyms get populated/filtered
Select a synonym
Grab the data from fungus

Why do you need to grab the data on synonym selection rather than directly when you select a fungus ?

? Offline

I'll try again to explain in abstract terms what I'm trying to do. I have a QListView in which names are to be displayed. It should be possible to distinguish between mushroom names, synonym names and German names. The whole thing I realize via QComboBox where I can select which model should be displayed (mFungusProxyModel, mSynonymProxyModel or mGermanNameModel). If for example in the QComboBox "Mushroom name" is selected and I choose one of thousands of mushrooms, all related data should be displayed in my QLineEdits etc. (see screenshot). If I select "Synonyms" in the QComboBox and select one out of thousands, all related data should appear.

A small example for this: I have a mushroom with the name "ABC" which has the associated synonym "XYZ". If I select "Mushroom names" in the QComboBox and then click on the mushroom "ABC", all data should appear. If I select then e.g. in the QComboBox "Synonyms" and click on the synonym "XYZ" the same data should appear as before with the mushroom "ABC".

And exactly for this I use the filtering in the mFungusProxyModel in the function synonymItemChanged()

Am I doing the whole thing correctly then or are there any suggestions for improvement?

SGaist

Ok, clearer now.

Did you consider using a QDataWidgetMapper to populate your widgets ?

That would simplify the data population part.

Set it to the correct entry on your table and voila.

Beside that, you need to decouple things a bit. You are trying to do too many things at the same time.

From the looks of it:

One model per possibility which are independent from each other as they have different purposes. The ones you use to populate your QListView
On selection, either extract the data from the index directly to populate your widgets or use QDataWidgetMapper to point to the correct records of the main model(s)

You can even consider using three QListView rather than swapping your proxies.

? Offline

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

Did you consider using a QDataWidgetMapper to populate your widgets ?

Yes, I use QDataWidgetMapper to populate my widgets

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

Beside that, you need to decouple things a bit. You are trying to do too many things at the same time.

What exactly do you mean by that? Can you explain that a bit more precisely and especially at what point?

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

One model per possibility which are independent from each other as they have different purposes. The ones you use to populate your QListView

I have that. mFungusProxyModel is for the table fungus, mSynonymProxyModel is for the table synonyms and mGermanNameProxyModel is for german name table.

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

On selection, either extract the data from the index directly to populate your widgets or use QDataWidgetMapper to point to the correct records of the main model(s)

What you say makes sense, but I don't know how to filter by ID if I'm only working with the QModelIndex, for example. Can you explain this to me in more detail? Maybe also with an example?

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

You can even consider using tree QListView rather than swapping your proxies.

Do you mean a QTreeView?

If I then put all the models in one QTreeView, how does the selection of the correct model work?

SGaist

My bad, three QListView not tree.

Get the source index from what was selected and then use QDataWidgetMapper::setCurrentModelIndex.

? Offline

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

My bad, three QListView not tree.

I almost thought that you meant three QListViews, but then I wasn't sure. The only question that comes to my mind is: How can I change the three QListViews? Since my GUI was created via the designer. How do I hide the ui->listview and how do I activate the QListView *secondList = new QListView; so that it fits into my layout?

SGaist

Put them in a QStackedWidget or QStackedLayout and switch the one to view based on your combo box selection.

? Offline

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

Put them in a QStackedWidget

I managed to do that and it works as expected.

@SGaist said in Singal not working correct when filtering in QSortFilterProxyModel:

Get the source index from what was selected and then use QDataWidgetMapper::setCurrentModelIndex.

I'm just not quite sure how you mean that. In my constructor I do this:

    secondList = new QListView;
    thirdList = new QListView;
    firstList = new QListView;
    firstList->setModel(mFungusProxyModel);
    firstList->setModelColumn(1);
    secondList->setModel(mSynonymProxyModel);
    secondList->setModelColumn(1);
    thirdList->setModel(mGermanNameProxyModel);
    thirdList->setModelColumn(0);

    ui->stackedWidget->addWidget(firstList);
    ui->stackedWidget->addWidget(secondList);
    ui->stackedWidget->addWidget(thirdList);

    connect(ui->modelSelection, QOverload<int>::of(&QComboBox::activated),
                ui->stackedWidget, &QStackedWidget::setCurrentIndex);
    connect(firstList->selectionModel(), &QItemSelectionModel::currentChanged, this, &MainWindow::fungusItemChanged);
    connect(secondList->selectionModel(), &QItemSelectionModel::currentChanged, this, &MainWindow::synonymItemChanged);

And my two slot's looks like this:

void MainWindow::fungusItemChanged(const QModelIndex &index) const
{
    const int id = mFungusProxyModel->data(index.siblingAtColumn(Column::Id)).toInt();
    const QString redlist = mFungusProxyModel->data(index.siblingAtColumn(Column::Assignment)).toString();

    if(redlist.isEmpty()){
        ui->redlist->setCurrentIndex(Index::None);
    }

    mSynonymFilterModel->setFilterRegularExpression(idFilter(id));
    mSynonymFilterModel->setFilterKeyColumn(Column::FungusId);

    ui->synonymList->setModel(mSynonymFilterModel);
    ui->synonymList->setModelColumn(Column::Name);

    mMapper->setCurrentModelIndex(index); //mMapper is QDataWidgetMapper

}

void MainWindow::synonymItemChanged(const QModelIndex &index) const
{
    const int id = mSynonymProxyModel->data(index.siblingAtColumn(Column::FungusId)).toInt();

    mFungusProxyModel->setFilterRegularExpression(idFilter(id)) ;
    mFungusProxyModel->setFilterKeyColumn(Column::Id);

    mSynonymFilterModel->setFilterRegularExpression(idFilter(id));
    mSynonymFilterModel->setFilterKeyColumn(Column::FungusId);

    ui->synonymList->setModel(mSynonymFilterModel);
    ui->synonymList->setModelColumn(Column::Name);

    QModelIndex fungusIndex = mFungusProxyModel->index(0,0);

    const QString redlist = mFungusProxyModel->data(fungusIndex.siblingAtColumn(Column::Assignment)).toString();

    if(redlist.isEmpty()){
        ui->redlist->setCurrentIndex(Index::None);
    }

    mMapper->setCurrentModelIndex(fungusIndex); //mMapper is QDataWidgetMapper
}

If I take now for example the secondList (synonym list) and select a synonym I receive the QModelIndex (by the connect it calls me the slot synonymItemChanged(QModelIndex)). But now it is not clear to me, how I should get from this QModelIndex of the mSynonymProxyModel to the one record of the mFungusProxyModel via the QModelIndex. Can you explain this to me?

SGaist

Which model did you set on your mapper ?