第2章：bookdelegate.cpp 到 bookdelegate.py¶

1from PySide6.QtWidgets import (QItemDelegate, QSpinBox, QStyledItemDelegate,
2    QStyle, QStyleOptionViewItem)
3from PySide6.QtGui import QMouseEvent, QPixmap, QPalette, QImage
4from PySide6.QtCore import QEvent, QSize, Qt, QUrl
5
6
7class BookDelegate(QSqlRelationalDelegate):
8    """Books delegate to rate the books"""

 1
 2    def __init__(self, parent=None):
 3        QSqlRelationalDelegate.__init__(self, parent)
 4        star_png = Path(__file__).parent / "images" / "star.png"
 5        self.star = QPixmap(star_png)
 6
 7    def paint(self, painter, option, index):
 8        """ Paint the items in the table.
 9
10            If the item referred to by <index> is a StarRating, we
11            handle the painting ourselves. For the other items, we
12            let the base class handle the painting as usual.
13
14            In a polished application, we'd use a better check than
15            the column number to find out if we needed to paint the
16            stars, but it works for the purposes of this example.
17        """
18        if index.column() != 5:
19            # Since we draw the grid ourselves:
20            opt = copy.copy(option)
21            opt.rect = option.rect.adjusted(0, 0, -1, -1)
22            QSqlRelationalDelegate.paint(self, painter, opt, index)
23        else:
24            model = index.model()
25            if option.state & QStyle.State_Enabled:
26                if option.state & QStyle.State_Active:
27                    color_group = QPalette.Normal
28                else:
29                    color_group = QPalette.Inactive
30            else:
31                color_group = QPalette.Disabled
32
33            if option.state & QStyle.State_Selected:
34                painter.fillRect(option.rect,
35                    option.palette.color(color_group, QPalette.Highlight))
36            rating = model.data(index, Qt.DisplayRole)
37            width = self.star.width()
38            height = self.star.height()
39            x = option.rect.x()
40            y = option.rect.y() + (option.rect.height() / 2) - (height / 2)
41            for i in range(rating):
42                painter.drawPixmap(x, y, self.star)
43                x += width
44
45            # Since we draw the grid ourselves:
46            self.drawFocus(painter, option, option.rect.adjusted(0, 0, -1, -1))
47
48        pen = painter.pen()
49        painter.setPen(option.palette.color(QPalette.Mid))
50        painter.drawLine(option.rect.bottomLeft(), option.rect.bottomRight())
51        painter.drawLine(option.rect.topRight(), option.rect.bottomRight())
52        painter.setPen(pen)
53
54    def sizeHint(self, option, index):
55        """ Returns the size needed to display the item in a QSize object. """
56        if index.column() == 5:
57            size_hint = QSize(5 * self.star.width(), self.star.height()) + QSize(1, 1)
58            return size_hint
59        # Since we draw the grid ourselves:
60        return QSqlRelationalDelegate.sizeHint(self, option, index) + QSize(1, 1)
61
62    def editorEvent(self, event, model, option, index):
63        if index.column() != 5:
64            return False
65
66        if event.type() == QEvent.MouseButtonPress:
67            mouse_pos = event.pos()
68            new_stars = int(0.7 + (mouse_pos.x() - option.rect.x()) / self.star.width())
69            stars = max(0, min(new_stars, 5))
70            model.setData(index, stars)
71            # So that the selection can change
72            return False
73
74        return True
75
76    def createEditor(self, parent, option, index):
77        if index.column() != 4:
78            return QSqlRelationalDelegate.createEditor(self, parent, option, index)
79
80        # For editing the year, return a spinbox with a range from -1000 to 2100.
81        spinbox = QSpinBox(parent)
82        spinbox.setFrame(False)
83        spinbox.setMaximum(2100)
84        spinbox.setMinimum(-1000)
85        return spinbox

 1from __future__ import annotations
 2
 3import sys
 4
 5from PySide6.QtCore import Qt
 6from PySide6.QtSql import QSqlQueryModel
 7from PySide6.QtWidgets import QTableView, QApplication
 8
 9import createdb
10from bookdelegate import BookDelegate
11
12if __name__ == "__main__":
13    app = QApplication()
14    createdb.init_db()
15
16    model = QSqlQueryModel()
17    model.setQuery("select title, author, genre, year, rating from books")
18
19    table = QTableView()
20    table.setModel(model)
21    table.setItemDelegate(BookDelegate())
22    table.resize(800, 600)
23    table.show()
24
25    sys.exit(app.exec())