mainwindow.cpp Example File

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  #include "mainwindow.h"
  #include "dialog.h"

  #include <QtWidgets>
  #include <QtSql>
  #include <QtXml>

  extern int uniqueAlbumId;
  extern int uniqueArtistId;

  MainWindow::MainWindow(const QString &artistTable, const QString &albumTable,
                         QFile *albumDetails, QWidget *parent)
       : QMainWindow(parent)
  {
      file = albumDetails;
      readAlbumData();

      model = new QSqlRelationalTableModel(this);
      model->setTable(albumTable);
      model->setRelation(2, QSqlRelation(artistTable, "id", "artist"));
      model->select();

      QGroupBox *artists = createArtistGroupBox();
      QGroupBox *albums = createAlbumGroupBox();
      QGroupBox *details = createDetailsGroupBox();

      artistView->setCurrentIndex(0);
      uniqueAlbumId = model->rowCount();
      uniqueArtistId = artistView->count();

      connect(model, SIGNAL(rowsInserted(QModelIndex,int,int)),
              this, SLOT(updateHeader(QModelIndex,int,int)));
      connect(model, SIGNAL(rowsRemoved(QModelIndex,int,int)),
              this, SLOT(updateHeader(QModelIndex,int,int)));

      QGridLayout *layout = new QGridLayout;
      layout->addWidget(artists, 0, 0);
      layout->addWidget(albums, 1, 0);
      layout->addWidget(details, 0, 1, 2, 1);
      layout->setColumnStretch(1, 1);
      layout->setColumnMinimumWidth(0, 500);

      QWidget *widget = new QWidget;
      widget->setLayout(layout);
      setCentralWidget(widget);
      createMenuBar();

      showImageLabel();
      resize(850, 400);
      setWindowTitle(tr("Music Archive"));
  }

  void MainWindow::changeArtist(int row)
  {
      if (row > 0) {
          QModelIndex index = model->relationModel(2)->index(row, 1);
          model->setFilter("artist = '" + index.data().toString() + '\'') ;
          showArtistProfile(index);
      } else if (row == 0) {
          model->setFilter(QString());
          showImageLabel();
      } else {
          return;
      }
  }

  void MainWindow::showArtistProfile(QModelIndex index)
  {
      QSqlRecord record = model->relationModel(2)->record(index.row());

      QString name = record.value("artist").toString();
      QString count = record.value("albumcount").toString();
      profileLabel->setText(tr("Artist : %1 \n" \
                               "Number of Albums: %2").arg(name).arg(count));

      profileLabel->show();
      iconLabel->show();

      titleLabel->hide();
      trackList->hide();
      imageLabel->hide();
  }

  void MainWindow::showAlbumDetails(QModelIndex index)
  {
      QSqlRecord record = model->record(index.row());

      QString artist = record.value("artist").toString();
      QString title = record.value("title").toString();
      QString year = record.value("year").toString();
      QString albumId = record.value("albumid").toString();

      showArtistProfile(indexOfArtist(artist));
      titleLabel->setText(tr("Title: %1 (%2)").arg(title).arg(year));
      titleLabel->show();

      QDomNodeList albums = albumData.elementsByTagName("album");
      for (int i = 0; i < albums.count(); i++) {
          QDomNode album = albums.item(i);
          if (album.toElement().attribute("id") == albumId) {
              getTrackList(album.toElement());
              break;
          }
      }
      if (trackList->count() != 0)
          trackList->show();
  }

  void MainWindow::getTrackList(QDomNode album)
  {
      trackList->clear();

      QDomNodeList tracks = album.childNodes();
      QDomNode track;
      QString trackNumber;

      for (int j = 0; j < tracks.count(); j++) {

          track = tracks.item(j);
          trackNumber = track.toElement().attribute("number");

          QListWidgetItem *item = new QListWidgetItem(trackList);
          item->setText(trackNumber + ": " + track.toElement().text());
      }
  }

  void MainWindow::addAlbum()
  {
      Dialog *dialog = new Dialog(model, albumData, file, this);
      int accepted = dialog->exec();

      if (accepted == 1) {
          int lastRow = model->rowCount() - 1;
          albumView->selectRow(lastRow);
          albumView->scrollToBottom();
          showAlbumDetails(model->index(lastRow, 0));
      }
  }

  void MainWindow::deleteAlbum()
  {
      QModelIndexList selection = albumView->selectionModel()->selectedRows(0);

      if (!selection.empty()) {
          QModelIndex idIndex = selection.at(0);
          int id = idIndex.data().toInt();
          QString title = idIndex.sibling(idIndex.row(), 1).data().toString();
          QString artist = idIndex.sibling(idIndex.row(), 2).data().toString();

          QMessageBox::StandardButton button;
          button = QMessageBox::question(this, tr("Delete Album"),
                                         tr("Are you sure you want to "
                                            "delete '%1' by '%2'?")
                                         .arg(title, artist),
                                         QMessageBox::Yes | QMessageBox::No);

          if (button == QMessageBox::Yes) {
              removeAlbumFromFile(id);
              removeAlbumFromDatabase(idIndex);
              decreaseAlbumCount(indexOfArtist(artist));

              showImageLabel();
          }
      } else {
          QMessageBox::information(this, tr("Delete Album"),
                                   tr("Select the album you want to delete."));
      }
  }

  void MainWindow::removeAlbumFromFile(int id)
  {

      QDomNodeList albums = albumData.elementsByTagName("album");

      for (int i = 0; i < albums.count(); i++) {
          QDomNode node = albums.item(i);
          if (node.toElement().attribute("id").toInt() == id) {
              albumData.elementsByTagName("archive").item(0).removeChild(node);
              break;
          }
      }
  /*
      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 (!file->open(QIODevice::WriteOnly)) {
          return;
      } else {
          QTextStream stream(file);
          albumData.elementsByTagName("archive").item(0).save(stream, 4);
          file->close();
      }
  */
  }

  void MainWindow::removeAlbumFromDatabase(QModelIndex index)
  {
      model->removeRow(index.row());
  }

  void MainWindow::decreaseAlbumCount(QModelIndex artistIndex)
  {
      int row = artistIndex.row();
      QModelIndex albumCountIndex = artistIndex.sibling(row, 2);
      int albumCount = albumCountIndex.data().toInt();

      QSqlTableModel *artists = model->relationModel(2);

      if (albumCount == 1) {
          artists->removeRow(row);
          showImageLabel();
      } else {
          artists->setData(albumCountIndex, QVariant(albumCount - 1));
      }
  }

  void MainWindow::readAlbumData()
  {
      if (!file->open(QIODevice::ReadOnly))
          return;

      if (!albumData.setContent(file)) {
          file->close();
          return;
      }
      file->close();
  }

  QGroupBox* MainWindow::createArtistGroupBox()
  {
      artistView = new QComboBox;
      artistView->setModel(model->relationModel(2));
      artistView->setModelColumn(1);

      connect(artistView, SIGNAL(currentIndexChanged(int)),
              this, SLOT(changeArtist(int)));

      QGroupBox *box = new QGroupBox(tr("Artist"));

      QGridLayout *layout = new QGridLayout;
      layout->addWidget(artistView, 0, 0);
      box->setLayout(layout);

      return box;
  }

  QGroupBox* MainWindow::createAlbumGroupBox()
  {
      QGroupBox *box = new QGroupBox(tr("Album"));

      albumView = new QTableView;
      albumView->setEditTriggers(QAbstractItemView::NoEditTriggers);
      albumView->setSortingEnabled(true);
      albumView->setSelectionBehavior(QAbstractItemView::SelectRows);
      albumView->setSelectionMode(QAbstractItemView::SingleSelection);
      albumView->setShowGrid(false);
      albumView->verticalHeader()->hide();
      albumView->setAlternatingRowColors(true);
      albumView->setModel(model);
      adjustHeader();

      QLocale locale = albumView->locale();
      locale.setNumberOptions(QLocale::OmitGroupSeparator);
      albumView->setLocale(locale);

      connect(albumView, SIGNAL(clicked(QModelIndex)),
              this, SLOT(showAlbumDetails(QModelIndex)));
      connect(albumView, SIGNAL(activated(QModelIndex)),
              this, SLOT(showAlbumDetails(QModelIndex)));

      QVBoxLayout *layout = new QVBoxLayout;
      layout->addWidget(albumView, 0, 0);
      box->setLayout(layout);

      return box;
  }

  QGroupBox* MainWindow::createDetailsGroupBox()
  {
      QGroupBox *box = new QGroupBox(tr("Details"));

      profileLabel = new QLabel;
      profileLabel->setWordWrap(true);
      profileLabel->setAlignment(Qt::AlignBottom);

      titleLabel = new QLabel;
      titleLabel->setWordWrap(true);
      titleLabel->setAlignment(Qt::AlignBottom);

      iconLabel = new QLabel();
      iconLabel->setAlignment(Qt::AlignBottom | Qt::AlignRight);
      iconLabel->setPixmap(QPixmap(":/images/icon.png"));

      imageLabel = new QLabel;
      imageLabel->setWordWrap(true);
      imageLabel->setAlignment(Qt::AlignCenter);
      imageLabel->setPixmap(QPixmap(":/images/image.png"));

      trackList = new QListWidget;

      QGridLayout *layout = new QGridLayout;
      layout->addWidget(imageLabel, 0, 0, 3, 2);
      layout->addWidget(profileLabel, 0, 0);
      layout->addWidget(iconLabel, 0, 1);
      layout->addWidget(titleLabel, 1, 0, 1, 2);
      layout->addWidget(trackList, 2, 0, 1, 2);
      layout->setRowStretch(2, 1);
      box->setLayout(layout);

      return box;
  }

  void MainWindow::createMenuBar()
  {
      QAction *addAction = new QAction(tr("&Add album..."), this);
      QAction *deleteAction = new QAction(tr("&Delete album..."), this);
      QAction *quitAction = new QAction(tr("&Quit"), this);
      QAction *aboutAction = new QAction(tr("&About"), this);
      QAction *aboutQtAction = new QAction(tr("About &Qt"), this);

      addAction->setShortcut(tr("Ctrl+A"));
      deleteAction->setShortcut(tr("Ctrl+D"));
      quitAction->setShortcuts(QKeySequence::Quit);

      QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
      fileMenu->addAction(addAction);
      fileMenu->addAction(deleteAction);
      fileMenu->addSeparator();
      fileMenu->addAction(quitAction);

      QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
      helpMenu->addAction(aboutAction);
      helpMenu->addAction(aboutQtAction);

      connect(addAction, SIGNAL(triggered(bool)), this, SLOT(addAlbum()));
      connect(deleteAction, SIGNAL(triggered(bool)), this, SLOT(deleteAlbum()));
      connect(quitAction, SIGNAL(triggered(bool)), this, SLOT(close()));
      connect(aboutAction, SIGNAL(triggered(bool)), this, SLOT(about()));
      connect(aboutQtAction, SIGNAL(triggered(bool)), qApp, SLOT(aboutQt()));
  }

  void MainWindow::showImageLabel()
  {
      profileLabel->hide();
      titleLabel->hide();
      iconLabel->hide();
      trackList->hide();

      imageLabel->show();
  }

  QModelIndex MainWindow::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();
  }

  void MainWindow::updateHeader(QModelIndex, int, int)
  {
      adjustHeader();
  }

  void MainWindow::adjustHeader()
  {
      albumView->hideColumn(0);
      albumView->horizontalHeader()->setSectionResizeMode(1, QHeaderView::Stretch);
      albumView->resizeColumnToContents(2);
      albumView->resizeColumnToContents(3);
  }

  void MainWindow::about()
  {
      QMessageBox::about(this, tr("About Music Archive"),
              tr("<p>The <b>Music Archive</b> example shows how to present "
                 "data from different data sources in the same application. "
                 "The album titles, and the corresponding artists and release dates, "
                 "are kept in a database, while each album's tracks are stored "
                 "in an XML file. </p><p>The example also shows how to add as "
                 "well as remove data from both the database and the "
                 "associated XML file using the API provided by the Qt SQL and "
                 "Qt XML modules, respectively.</p>"));
  }