dialog.cpp Example File

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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;
  }