Qt 5.11 | Qt SQL | Master Detail Example | dialog.cpp Example File

Qt 5.11.3 Reference Documentation

# dialog.cpp Example File

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, const 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, &QPushButton::clicked, this, &Dialog::close);
          connect(revertButton, &QPushButton::clicked,  this, &Dialog::revert);
          connect(submitButton, &QPushButton::clicked, this, &Dialog::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;
      }