QSortFilterProxyModel strange behavior with QRegExp

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@JonB said in QSortFilterProxyModel strange behavior with QRegExp:

Try using \S in place of \w. Any difference?

No difference.

@JonB said in QSortFilterProxyModel strange behavior with QRegExp:

Try using ., or even (.|\n), in place of \w. Any difference?

No difference.

@JonB said in QSortFilterProxyModel strange behavior with QRegExp:

You are going to move over from QRegExp to QRegularExpression, aren't you?

I switched to QRegularExrpession. Now my code looks like this:

void MainWindow::on_searchbar_textChanged(const QString &name)
{
    QRegularExpression regularExpression;
    regularExpression.setPatternOptions(QRegularExpression::CaseInsensitiveOption);

    ui->selection->setCurrentIndex(0);
    if(ui->selection->currentIndex() == 0)
    {
        mFungusProxyModel->setFilterCaseSensitivity(Qt::CaseInsensitive);
        mFungusProxyModel->setFilterKeyColumn(1);
        if(name.contains(QRegularExpression("\\s")))
        {
            QStringList word = name.split(QRegularExpression("\\s"));
            regularExpression.setPattern("^" + QRegularExpression::escape(word[0]) + "\\w*\\s" + QRegularExpression::escape(word[1]) + "\\w*");
        }
        else
        {
            regularExpression.setPattern("^" + QRegularExpression::escape(name) + "\\w*");
        }
        mFungusProxyModel->setFilterRegularExpression(regularExpression);
        ui->listView->setModelColumn(1);
        ui->listView->setModel(mFungusProxyModel);
    }
}

Here's what else I found out: If I enter "bole" instead of "bol" then the search starts and lists all names that start with "bole".

I suspect it is the QSortFilterProxyModel. Can I somehow say there I want to search for 3 letters? Unfortunately I didn't find anything in the documentation.

Do you have any other idea how I can implement this differently?

JonB

@Gabber
Using the regular expression filter in QSortFilterProxyModel is only a "convenience" for you, you don't have to use it. You can subclass and and implement your own code for virtual protected bool QSortFilterProxyModel::filterAcceptsRow() if you cannot get the regular expression to work right for some reason.

SGaist

The length of the expression should have no importance as long it's properly written.

Can you write a minimal compilable example that uses a QStandardItemModel with some suitable entries and your proxy setup so that we can test it ?

Note that you can also to some testing with the QRegularExpression tool from Qt's examples.

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@SGaist
I have made a very simple example that corresponds to what I want to search. If I take the QStandardItemModel my QRegularExpression also works as expected with QSortFilterProxyModel. Here is my code.

main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->comboBox->addItem("Vollnamen");
    ui->comboBox->setCurrentText("Vollnamen");
    QStringList fungusList{
        "Boletus aereus Bulliard ex Fr.",
        "Boletus betulicola (Vassilkov) Pilat & Dermek",
        "Boletus carpinaceus Velen.",
        "Boletus edulis Bulliard",
        "Boletus edulis var.arenarius Engel, Krglst. & Dermek",
        "Boletus edulis var.clavipes Peck",
        "Abortiporus biennis (Bull.) Singer",
        "Adustomyces spec.",
        "Euryachora spec",
        "Diaporthe strumella (Fries) Fuckel",
        "Cudonia spec."
    };

    mFungusListModel = new QStandardItemModel(fungusList.count(),0);
    for(int row=0; row<mFungusListModel->rowCount(); row++){
        QStandardItem *item = new QStandardItem(QString(fungusList.at(row)));
        mFungusListModel->setItem(row,0,item);
    }


    mFungusProxyModel = new QSortFilterProxyModel();
    mFungusListModel->sort(0);
    mFungusProxyModel->setSourceModel(mFungusListModel);
    ui->listView->setModel(mFungusProxyModel);
    ui->listView->setModelColumn(0);

}

MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_lineEdit_textChanged(const QString &name)
{
    QRegularExpression regularExpression;
    regularExpression.setPatternOptions(QRegularExpression::CaseInsensitiveOption);

    ui->comboBox->setCurrentIndex(0);
    if(ui->comboBox->currentIndex() == 0)
    {
        mFungusProxyModel->setFilterCaseSensitivity(Qt::CaseInsensitive);
        mFungusProxyModel->setFilterKeyColumn(0);
        if(name.contains(QRegularExpression("\\s")))
        {
            QStringList word = name.split(QRegularExpression("\\s"));
            regularExpression.setPattern("^" + QRegularExpression::escape(word[0]) + "\\w*\\s" + QRegularExpression::escape(word[1]) + "\\w*");
        }
        else
        {
            regularExpression.setPattern("^" + QRegularExpression::escape(name) + "\\w*");
        }
        mFungusProxyModel->setFilterRegularExpression(regularExpression);
        ui->listView->setModelColumn(0);
        ui->listView->setModel(mFungusProxyModel);
    }
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QSortFilterProxyModel>
#include <QStandardItemModel>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_lineEdit_textChanged(const QString &name);

private:
    Ui::MainWindow *ui;
    QSortFilterProxyModel *mFungusProxyModel;
    QStandardItemModel *mFungusListModel;
};
#endif // MAINWINDOW_H

mainwindow.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>424</width>
    <height>590</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
     <widget class="QLineEdit" name="lineEdit"/>
    </item>
    <item>
     <widget class="QComboBox" name="comboBox"/>
    </item>
    <item>
     <widget class="QListView" name="listView"/>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>424</width>
     <height>23</height>
    </rect>
   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <resources/>
 <connections/>
</ui>

What could be the problem now? Do you have another idea? Do you need any code to analyze the problem? I hope we can work this out somehow. The search function is the most important thing in the program.

Thanks already :)

SGaist

@Gabber said in QSortFilterProxyModel strange behavior with QRegExp:

If I take the QStandardItemModel my QRegularExpression also works as expected with QSortFilterProxyModel.

Do you mean that with the QStandardItemModel the erroneous behaviour does not trigger ?

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@SGaist said in QSortFilterProxyModel strange behavior with QRegExp:

Do you mean that with the QStandardItemModel the erroneous behaviour does not trigger ?

Yes, that's what I mean. My search works exactly as I imagine it.

SGaist

In that case, the problem might be with mFungusModel.

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@SGaist
I have created a file DatabaseManager.cpp. The following function exists in it:

QSqlTableModel *DatabaseManager::fungusTable() const
{
    QSqlTableModel *model = new QSqlTableModel();
    model->setTable("Pilze");
    model->setSort(1, Qt::AscendingOrder);
    model->select();
    return model;
}

In my mainwindow.h I do this:

private:
    Ui::MainWindow *ui;
    DatabaseManager *mDatabaseManager;
    SettingsManager *mSettingsManager;
    QDataWidgetMapper *mFungusMapper;
    QSqlTableModel *mFungusModel;

And in my constructor in my mainwindow.cpp I assign the data from the DatabaseManager to mFungusModel.

[...]
    if(isStandardDatabasePathSet)
    {
        const QString standardDatabase = mSettingsManager->loadStandardDatabase();

        mDatabaseManager->openDatabase(standardDatabase);

        ui->selection->setCurrentText("Vollnamen");

        mFungusMapper = new QDataWidgetMapper();
        mFungusProxyModel = new QSortFilterProxyModel();

        mFungusModel = mDatabaseManager->fungusTable();

        mFungusProxyModel->setSourceModel(mFungusModel);
        ui->listView->setModel(mFungusProxyModel);
        ui->listView->setModelColumn(1);
    }
[...]

That's all what I'm doing in my constructor of mainwindow.cpp

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Can someone please give me a hint what I can do now?

Why does the search work when I type four characters or type three characters and delete one?

I have no idea what to look for to solve / address this problem.

Tips are gratefully accepted.

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My problem was solved in this Thread:
https://forum.qt.io/topic/131616/does-qsqltablemodel-have-a-limit-of-records