第3章：将bookdwindow.cpp移植到bookwindow.py¶

 1    // Initialize the database:
 2    QSqlError err = initDb();
 3    if (err.type() != QSqlError::NoError) {
 4        showError(err);
 5        return;
 6    }
 7
 8    // Create the data model:
 9    model = new QSqlRelationalTableModel(ui.bookTable);
10    model->setEditStrategy(QSqlTableModel::OnManualSubmit);
11    model->setTable("books");
12
13    // Remember the indexes of the columns:
14    authorIdx = model->fieldIndex("author");
15    genreIdx = model->fieldIndex("genre");
16
17    // Set the relations to the other database tables:
18    model->setRelation(authorIdx, QSqlRelation("authors", "id", "name"));
19    model->setRelation(genreIdx, QSqlRelation("genres", "id", "name"));
20
21    // Set the localized header captions:
22    model->setHeaderData(authorIdx, Qt::Horizontal, tr("Author Name"));
23    model->setHeaderData(genreIdx, Qt::Horizontal, tr("Genre"));
24    model->setHeaderData(model->fieldIndex("title"),
25                         Qt::Horizontal, tr("Title"));
26    model->setHeaderData(model->fieldIndex("year"), Qt::Horizontal, tr("Year"));
27    model->setHeaderData(model->fieldIndex("rating"),
28                         Qt::Horizontal, tr("Rating"));
29
30    // Populate the model:
31    if (!model->select()) {
32        showError(model->lastError());
33        return;
34    }
35
36    // Set the model and hide the ID column:
37    ui.bookTable->setModel(model);
38    ui.bookTable->setItemDelegate(new BookDelegate(ui.bookTable));
39    ui.bookTable->setColumnHidden(model->fieldIndex("id"), true);
40    ui.bookTable->setSelectionMode(QAbstractItemView::SingleSelection);
41
42    // Initialize the Author combo box:
43    ui.authorEdit->setModel(model->relationModel(authorIdx));
44    ui.authorEdit->setModelColumn(
45                model->relationModel(authorIdx)->fieldIndex("name"));
46
47    ui.genreEdit->setModel(model->relationModel(genreIdx));
48    ui.genreEdit->setModelColumn(
49                model->relationModel(genreIdx)->fieldIndex("name"));
50
51    // Lock and prohibit resizing of the width of the rating column:
52    ui.bookTable->horizontalHeader()->setSectionResizeMode(
53                model->fieldIndex("rating"),
54                QHeaderView::ResizeToContents);
55
56    QDataWidgetMapper *mapper = new QDataWidgetMapper(this);
57    mapper->setModel(model);
58    mapper->setItemDelegate(new BookDelegate(this));
59    mapper->addMapping(ui.titleEdit, model->fieldIndex("title"));
60    mapper->addMapping(ui.yearEdit, model->fieldIndex("year"));
61    mapper->addMapping(ui.authorEdit, authorIdx);
62    mapper->addMapping(ui.genreEdit, genreIdx);
63    mapper->addMapping(ui.ratingEdit, model->fieldIndex("rating"));
64
65    connect(ui.bookTable->selectionModel(),
66            &QItemSelectionModel::currentRowChanged,
67            mapper,
68            &QDataWidgetMapper::setCurrentModelIndex
69            );
70
71    ui.bookTable->setCurrentIndex(model->index(0, 0));
72    createMenuBar();
73}
74
75void BookWindow::showError(const QSqlError &err)
76{
77    QMessageBox::critical(this, "Unable to initialize Database",
78                "Error initializing database: " + err.text());
79}
80
81void BookWindow::createMenuBar()
82{
83    QAction *quitAction = new QAction(tr("&Quit"), this);

 1    mapper->setItemDelegate(new BookDelegate(this));
 2    mapper->addMapping(ui.titleEdit, model->fieldIndex("title"));
 3    mapper->addMapping(ui.yearEdit, model->fieldIndex("year"));
 4    mapper->addMapping(ui.authorEdit, authorIdx);
 5    mapper->addMapping(ui.genreEdit, genreIdx);
 6    mapper->addMapping(ui.ratingEdit, model->fieldIndex("rating"));
 7
 8    connect(ui.bookTable->selectionModel(),
 9            &QItemSelectionModel::currentRowChanged,
10            mapper,
11            &QDataWidgetMapper::setCurrentModelIndex
12            );
13
14    ui.bookTable->setCurrentIndex(model->index(0, 0));
15    createMenuBar();
16}
17
18void BookWindow::showError(const QSqlError &err)
19{
20    QMessageBox::critical(this, "Unable to initialize Database",
21                "Error initializing database: " + err.text());
22}
23
24void BookWindow::createMenuBar()
25{
26    QAction *quitAction = new QAction(tr("&Quit"), this);
27    QAction *aboutAction = new QAction(tr("&About"), this);
28    QAction *aboutQtAction = new QAction(tr("&About Qt"), this);
29
30    QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
31    fileMenu->addAction(quitAction);
32
33    QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
34    helpMenu->addAction(aboutAction);
35    helpMenu->addAction(aboutQtAction);
36
37    connect(quitAction, &QAction::triggered, this, &BookWindow::close);
38    connect(aboutAction, &QAction::triggered, this, &BookWindow::about);
39    connect(aboutQtAction, &QAction::triggered, qApp, &QApplication::aboutQt);
40}
41
42void BookWindow::about()
43{
44    QMessageBox::about(this, tr("About Books"),
45            tr("<p>The <b>Books</b> example shows how to use Qt SQL classes "
46               "with a model/view framework."));
47}