Qt 4.6: bookwindow.cpp Example File (demos/books/bookwindow.cpp)

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# bookwindow.cpp Example File
demos/books/bookwindow.cpp

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     #include "bookwindow.h"
     #include "bookdelegate.h"
     #include "initdb.h"

     #include <QtSql>

     BookWindow::BookWindow()
     {
         ui.setupUi(this);

         if (!QSqlDatabase::drivers().contains("QSQLITE"))
             QMessageBox::critical(this, "Unable to load database", "This demo needs the SQLITE driver");

         // initialize the database
         QSqlError err = initDb();
         if (err.type() != QSqlError::NoError) {
             showError(err);
             return;
         }

         // Create the data model
         model = new QSqlRelationalTableModel(ui.bookTable);
         model->setEditStrategy(QSqlTableModel::OnManualSubmit);
         model->setTable("books");

         // Remeber the indexes of the columns
         authorIdx = model->fieldIndex("author");
         genreIdx = model->fieldIndex("genre");

         // Set the relations to the other database tables
         model->setRelation(authorIdx, QSqlRelation("authors", "id", "name"));
         model->setRelation(genreIdx, QSqlRelation("genres", "id", "name"));

         // Set the localized header captions
         model->setHeaderData(authorIdx, Qt::Horizontal, tr("Author Name"));
         model->setHeaderData(genreIdx, Qt::Horizontal, tr("Genre"));
         model->setHeaderData(model->fieldIndex("title"), Qt::Horizontal, tr("Title"));
         model->setHeaderData(model->fieldIndex("year"), Qt::Horizontal, tr("Year"));
         model->setHeaderData(model->fieldIndex("rating"), Qt::Horizontal, tr("Rating"));

         // Populate the model
         if (!model->select()) {
             showError(model->lastError());
             return;
         }

         // Set the model and hide the ID column
         ui.bookTable->setModel(model);
         ui.bookTable->setItemDelegate(new BookDelegate(ui.bookTable));
         ui.bookTable->setColumnHidden(model->fieldIndex("id"), true);
         ui.bookTable->setSelectionMode(QAbstractItemView::SingleSelection);

         // Initialize the Author combo box
         ui.authorEdit->setModel(model->relationModel(authorIdx));
         ui.authorEdit->setModelColumn(model->relationModel(authorIdx)->fieldIndex("name"));

         ui.genreEdit->setModel(model->relationModel(genreIdx));
         ui.genreEdit->setModelColumn(model->relationModel(genreIdx)->fieldIndex("name"));

         QDataWidgetMapper *mapper = new QDataWidgetMapper(this);
         mapper->setModel(model);
         mapper->setItemDelegate(new BookDelegate(this));
         mapper->addMapping(ui.titleEdit, model->fieldIndex("title"));
         mapper->addMapping(ui.yearEdit, model->fieldIndex("year"));
         mapper->addMapping(ui.authorEdit, authorIdx);
         mapper->addMapping(ui.genreEdit, genreIdx);
         mapper->addMapping(ui.ratingEdit, model->fieldIndex("rating"));

         connect(ui.bookTable->selectionModel(), SIGNAL(currentRowChanged(QModelIndex,QModelIndex)),
                 mapper, SLOT(setCurrentModelIndex(QModelIndex)));

         ui.bookTable->setCurrentIndex(model->index(0, 0));
     }

     void BookWindow::showError(const QSqlError &err)
     {
         QMessageBox::critical(this, "Unable to initialize Database",
                     "Error initializing database: " + err.text());
     }