Qt 4.0: bookwindow.cpp Example File (demos/books/bookwindow.cpp)

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

        #include <QtSql>

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

        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->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);

            // 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"));

            connect(model, SIGNAL(dataChanged(QModelIndex,QModelIndex)),
                    this, SLOT(dataChanged(QModelIndex)));
            connect(ui.bookTable->selectionModel(), SIGNAL(currentRowChanged(QModelIndex,QModelIndex)),
                    this, SLOT(currentBookChanged(QModelIndex)));
        }

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

        void BookWindow::currentBookChanged(const QModelIndex &index)
        {
            bool enabled = index.isValid();
            ui.titleEdit->setEnabled(enabled);
            ui.yearEdit->setEnabled(enabled);
            ui.authorEdit->setEnabled(enabled);
            ui.genreEdit->setEnabled(enabled);
            ui.ratingEdit->setEnabled(enabled);

            QSqlRecord rec = model->record(index.row());
            ui.titleEdit->setText(rec.value("title").toString());
            ui.yearEdit->setValue(rec.value("year").toInt());
            ui.authorEdit->setCurrentIndex(ui.authorEdit->findText(rec.value(authorIdx).toString()));
            ui.genreEdit->setCurrentIndex(ui.genreEdit->findText(rec.value(genreIdx).toString()));
            ui.ratingEdit->setCurrentIndex(rec.value("rating").toInt());
        }

        void BookWindow::on_authorEdit_activated(const QString &text)
        {
            QModelIndex currentIndex = model->index(ui.bookTable->currentIndex().row(), authorIdx);
            if (model->data(currentIndex).toString() != text)
                ui.bookTable->itemDelegate()->setModelData(ui.authorEdit, model, currentIndex);
        }

        void BookWindow::on_genreEdit_activated(const QString &text)
        {
            QModelIndex currentIndex = model->index(ui.bookTable->currentIndex().row(), genreIdx);
            if (model->data(currentIndex).toString() != text)
                ui.bookTable->itemDelegate()->setModelData(ui.genreEdit, model, currentIndex);
        }

        void BookWindow::on_ratingEdit_activated(int value)
        {
            QModelIndex currentIndex = model->index(ui.bookTable->currentIndex().row(),
                    model->fieldIndex("rating"));
            if (model->data(currentIndex).toInt() != value)
                model->setData(currentIndex, value);
        }

        void BookWindow::on_titleEdit_textChanged(const QString &text)
        {
            QModelIndex currentIndex = model->index(ui.bookTable->currentIndex().row(),
                    model->fieldIndex("title"));
            if (model->data(currentIndex).toString() != text)
                model->setData(currentIndex, text);
        }

        void BookWindow::on_yearEdit_valueChanged(int value)
        {
            QModelIndex currentIndex = model->index(ui.bookTable->currentIndex().row(),
                    model->fieldIndex("year"));
            if (model->data(currentIndex).toInt() != value)
                model->setData(currentIndex, value);
        }

        void BookWindow::dataChanged(const QModelIndex &index)
        {
            if (index.row() == ui.bookTable->currentIndex().row())
                currentBookChanged(index);
        }