Qt Reference Documentation

# dialog.cpp Example File

sql/masterdetail/dialog.cpp

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     #include "dialog.h"

     int uniqueAlbumId;
     int uniqueArtistId;

     Dialog::Dialog(QSqlRelationalTableModel *albums, QDomDocument details,
                    QFile *output, QWidget *parent)
          : QDialog(parent)
     {
         model = albums;
         albumDetails = details;
         outputFile = output;

         QGroupBox *inputWidgetBox = createInputWidgets();
         QDialogButtonBox *buttonBox = createButtons();

         QVBoxLayout *layout = new QVBoxLayout;
         layout->addWidget(inputWidgetBox);
         layout->addWidget(buttonBox);
         setLayout(layout);

         setWindowTitle(tr("Add Album"));
     }

     void Dialog::submit()
     {
         QString artist = artistEditor->text();
         QString title = titleEditor->text();

         if (artist.isEmpty() || title.isEmpty()) {
             QString message(tr("Please provide both the name of the artist "
                                "and the title of the album."));
             QMessageBox::information(this, tr("Add Album"), message);
         } else {
             int artistId = findArtistId(artist);
             int albumId = addNewAlbum(title, artistId);

             QStringList tracks;
             tracks = tracksEditor->text().split(',', QString::SkipEmptyParts);
             addTracks(albumId, tracks);

             increaseAlbumCount(indexOfArtist(artist));
             accept();
         }
     }

     int Dialog::findArtistId(const QString &artist)
     {
         QSqlTableModel *artistModel = model->relationModel(2);
         int row = 0;

         while (row < artistModel->rowCount()) {
             QSqlRecord record = artistModel->record(row);
             if (record.value("artist") == artist)
                 return record.value("id").toInt();
             else
                 row++;
         }
         return addNewArtist(artist);
     }

     int Dialog::addNewArtist(const QString &name)
     {
         QSqlTableModel *artistModel = model->relationModel(2);
         QSqlRecord record;

         int id = generateArtistId();

         QSqlField f1("id", QVariant::Int);
         QSqlField f2("artist", QVariant::String);
         QSqlField f3("albumcount", QVariant::Int);

         f1.setValue(QVariant(id));
         f2.setValue(QVariant(name));
         f3.setValue(QVariant(0));
         record.append(f1);
         record.append(f2);
         record.append(f3);

         artistModel->insertRecord(-1, record);
         return id;
     }

     int Dialog::addNewAlbum(const QString &title, int artistId)
     {
         int id = generateAlbumId();
         QSqlRecord record;

         QSqlField f1("albumid", QVariant::Int);
         QSqlField f2("title", QVariant::String);
         QSqlField f3("artistid", QVariant::Int);
         QSqlField f4("year", QVariant::Int);

         f1.setValue(QVariant(id));
         f2.setValue(QVariant(title));
         f3.setValue(QVariant(artistId));
         f4.setValue(QVariant(yearEditor->value()));
         record.append(f1);
         record.append(f2);
         record.append(f3);
         record.append(f4);

         model->insertRecord(-1, record);
         return id;
     }

     void Dialog::addTracks(int albumId, QStringList tracks)
     {
         QDomElement albumNode = albumDetails.createElement("album");
         albumNode.setAttribute("id", albumId);

         for (int i = 0; i < tracks.count(); i++) {
             QString trackNumber = QString::number(i);
             if (i < 10)
                 trackNumber.prepend("0");

             QDomText textNode = albumDetails.createTextNode(tracks.at(i));

             QDomElement trackNode = albumDetails.createElement("track");
             trackNode.setAttribute("number", trackNumber);
             trackNode.appendChild(textNode);

             albumNode.appendChild(trackNode);
         }

         QDomNodeList archive = albumDetails.elementsByTagName("archive");
         archive.item(0).appendChild(albumNode);

     /*
         The following code is commented out since the example uses an in
         memory database, i.e., altering the XML file will bring the data
         out of sync.

         if (!outputFile->open(QIODevice::WriteOnly)) {
             return;
         } else {
             QTextStream stream(outputFile);
             archive.item(0).save(stream, 4);
             outputFile->close();
         }
     */
     }

     void Dialog::increaseAlbumCount(QModelIndex artistIndex)
     {
         QSqlTableModel *artistModel = model->relationModel(2);

         QModelIndex albumCountIndex;
         albumCountIndex = artistIndex.sibling(artistIndex.row(), 2);

         int albumCount = albumCountIndex.data().toInt();
         artistModel->setData(albumCountIndex, QVariant(albumCount + 1));
     }

     void Dialog::revert()
     {
         artistEditor->clear();
         titleEditor->clear();
         yearEditor->setValue(QDate::currentDate().year());
         tracksEditor->clear();
     }

     QGroupBox *Dialog::createInputWidgets()
     {
         QGroupBox *box = new QGroupBox(tr("Add Album"));

         QLabel *artistLabel = new QLabel(tr("Artist:"));
         QLabel *titleLabel = new QLabel(tr("Title:"));
         QLabel *yearLabel = new QLabel(tr("Year:"));
         QLabel *tracksLabel = new QLabel(tr("Tracks (separated by comma):"));

         artistEditor = new QLineEdit;
         titleEditor = new QLineEdit;

         yearEditor = new QSpinBox;
         yearEditor->setMinimum(1900);
         yearEditor->setMaximum(QDate::currentDate().year());
         yearEditor->setValue(yearEditor->maximum());
         yearEditor->setReadOnly(false);

         tracksEditor = new QLineEdit;

         QGridLayout *layout = new QGridLayout;
         layout->addWidget(artistLabel, 0, 0);
         layout->addWidget(artistEditor, 0, 1);
         layout->addWidget(titleLabel, 1, 0);
         layout->addWidget(titleEditor, 1, 1);
         layout->addWidget(yearLabel, 2, 0);
         layout->addWidget(yearEditor, 2, 1);
         layout->addWidget(tracksLabel, 3, 0, 1, 2);
         layout->addWidget(tracksEditor, 4, 0, 1, 2);
         box->setLayout(layout);

         return box;
     }

     QDialogButtonBox *Dialog::createButtons()
     {
         QPushButton *closeButton = new QPushButton(tr("&Close"));
         QPushButton *revertButton = new QPushButton(tr("&Revert"));
         QPushButton *submitButton = new QPushButton(tr("&Submit"));

         closeButton->setDefault(true);

         connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
         connect(revertButton, SIGNAL(clicked()), this, SLOT(revert()));
         connect(submitButton, SIGNAL(clicked()), this, SLOT(submit()));

         QDialogButtonBox *buttonBox = new QDialogButtonBox;
         buttonBox->addButton(submitButton, QDialogButtonBox::ResetRole);
         buttonBox->addButton(revertButton, QDialogButtonBox::ResetRole);
         buttonBox->addButton(closeButton, QDialogButtonBox::RejectRole);

         return buttonBox;
     }

     QModelIndex Dialog::indexOfArtist(const QString &artist)
     {
         QSqlTableModel *artistModel = model->relationModel(2);

         for (int i = 0; i < artistModel->rowCount(); i++) {
             QSqlRecord record =  artistModel->record(i);
             if (record.value("artist") == artist)
                 return artistModel->index(i, 1);
         }

         return QModelIndex();
     }

     int Dialog::generateArtistId()
     {
         uniqueArtistId += 1;
         return uniqueArtistId;
     }

     int Dialog::generateAlbumId()
     {
         uniqueAlbumId += 1;
         return uniqueAlbumId;
     }