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;
 }