python - 如何在 Qt5 中调整父级大小后调整方形子级小部件的大小？

Question

我想用方形小部件做板。当我运行代码时，它会创建漂亮的板，但在调整大小后它看起来很丑。我正在尝试使用 resize Event 调整它的大小，但它存在（可能是一些错误）。我不知道如何在调整父母大小后调整孩子的大小。

儿童小部件必须是正方形，所以这也是问题，因为我不能使用自动扩展。也许这是一个简单的问题，但我找不到解决方案。我花了几个小时测试不同的想法，但它现在可以正常工作了。

这是我想要调整大小（单击最大化）：

最大化后它看起来很丑（我应该更改子小部件，但是在什么事件上（我认为在 resizeEvent 但它不起作用）以及如何（从父级或子级设置导致程序退出）。

这是我的最小化代码：

import logging
import sys

from PyQt5 import QtCore, QtGui
from PyQt5.QtCore import QSize
from PyQt5.QtGui import QFont, QPaintEvent, QPainter
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout


class Application(QApplication):
    pass


class Board(QWidget):
    def square_size(self):
        size = self.size()
        min_size = min(size.height(), size.width())
        min_size_1_8 = min_size // 8
        square_size = QSize(min_size_1_8, min_size_1_8)
        logging.debug(square_size)
        return square_size

    def __init__(self, parent=None):
        super().__init__(parent=parent)

        square_size = self.square_size()

        grid = QGridLayout()
        grid.setSpacing(0)

        squares = []
        for x in range(8):
            for y in range(8):
                square = Square(self, (x + y - 1) % 2)
                squares.append(squares)
                square.setFixedSize(square_size)
                grid.addWidget(square, x, y)
        self.squares = squares
        self.setLayout(grid)

    def resizeEvent(self, event: QtGui.QResizeEvent) -> None:
        # how to resize children?
        logging.debug('Resize %s.', self.__class__.__name__)
        logging.debug('Size %s.', event.size())
        super().resizeEvent(event)


class Square(QWidget):
    def __init__(self, parent, color):
        super().__init__(parent=parent)
        if color:
            self.color = QtCore.Qt.white
        else:
            self.color = QtCore.Qt.black

    def resizeEvent(self, event: QtGui.QResizeEvent) -> None:
        logging.debug('Resize %s.', self.__class__.__name__)
        logging.debug('Size %s.', event.size())
        super().resizeEvent(event)

    def paintEvent(self, event: QPaintEvent) -> None:
        painter = QPainter()
        painter.begin(self)
        painter.fillRect(self.rect(), self.color)
        painter.end()


def main():
    logging.basicConfig(level=logging.DEBUG)
    app = Application(sys.argv)
    app.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling, True)

    default_font = QFont()
    default_font.setPointSize(12)
    app.setFont(default_font)

    board = Board()
    board.setWindowTitle('Board')
    # ugly look
    # chessboard.showMaximized()
    # looks nize but resize not works
    board.show()

    sys.exit(app.exec())


if __name__ == '__main__':
    main()

我应该如何调整方形孩子的大小以避免孔？

第二次尝试 - 改进的代码，但我仍然不知道如何调整孩子的大小

一些将其居中的新想法效果更好（现在没有间隙），但我仍然不知道如何调整孩子的大小（没有崩溃）。

在显示（）之后：

太宽（保持比例）：

太高（保持比例）：

更大（它保持比例但孩子没有缩放到可用空间 - 我不知道如何调整孩子的大小？）：

改进的代码：

import logging
import sys

from PyQt5 import QtCore, QtGui
from PyQt5.QtCore import QSize
from PyQt5.QtGui import QFont, QPaintEvent, QPainter
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QHBoxLayout, QVBoxLayout


class Application(QApplication):
    pass


class Board(QWidget):
    def square_size(self):
        size = self.size()
        min_size = min(size.height(), size.width())
        min_size_1_8 = min_size // 8
        square_size = QSize(min_size_1_8, min_size_1_8)
        logging.debug(square_size)
        return square_size

    def __init__(self, parent=None):
        super().__init__(parent=parent)

        square_size = self.square_size()

        vertical = QVBoxLayout()
        horizontal = QHBoxLayout()

        grid = QGridLayout()
        grid.setSpacing(0)

        squares = []
        for x in range(8):
            for y in range(8):
                square = Square(self, (x + y - 1) % 2)
                squares.append(squares)
                square.setFixedSize(square_size)
                grid.addWidget(square, x, y)
        self.squares = squares

        horizontal.addStretch()
        horizontal.addLayout(grid)
        horizontal.addStretch()
        vertical.addStretch()
        vertical.addLayout(horizontal)
        vertical.addStretch()
        self.setLayout(vertical)

    def resizeEvent(self, event: QtGui.QResizeEvent) -> None:
        # how to resize children?
        logging.debug('Resize %s.', self.__class__.__name__)
        logging.debug('Size %s.', event.size())
        super().resizeEvent(event)


class Square(QWidget):
    def __init__(self, parent, color):
        super().__init__(parent=parent)
        if color:
            self.color = QtCore.Qt.white
        else:
            self.color = QtCore.Qt.black

    def resizeEvent(self, event: QtGui.QResizeEvent) -> None:
        logging.debug('Resize %s.', self.__class__.__name__)
        logging.debug('Size %s.', event.size())
        super().resizeEvent(event)

    def paintEvent(self, event: QPaintEvent) -> None:
        painter = QPainter()
        painter.begin(self)
        painter.fillRect(self.rect(), self.color)
        painter.end()


def main():
    logging.basicConfig(level=logging.DEBUG)
    app = Application(sys.argv)
    app.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling, True)

    default_font = QFont()
    default_font.setPointSize(12)
    app.setFont(default_font)

    board = Board()
    board.setWindowTitle('Board')
    # ugly look
    # chessboard.showMaximized()
    # looks nice but resize not works
    board.show()

    sys.exit(app.exec())


if __name__ == '__main__':
    main()

我应该如何调整方形孩子的大小而不会崩溃？

标签： pythonpython-3.xpyqtpyqt5qgridlayout

Answer 1

有两种可能的解决方案。
您可以使用Graphics View 框架，该框架专门用于必须考虑自定义/特定图形和定位的此类应用程序，否则创建布局子类。虽然在这种情况下重新实现布局有点简单，但一旦应用程序变得更加复杂，您可能会遇到一些问题。另一方面，Graphics View 框架有一个陡峭的学习曲线，因为您需要了解它的工作原理以及对象交互的行为方式。

子类化布局

假设平方数始终相同，您可以重新实现自己的布局，该布局将根据其内容设置正确的几何图形。

在此示例中，我还创建了一个带有其他小部件的“容器”，以显示正在调整大小。

当窗口宽度非常高时，它会以高度为参考，水平居中：

相反，当高度较大时，它将垂直居中：

请记住，您不应该在板上添加其他小部件，否则您会遇到严重的问题。
这并非不可能，但它的实现可能要复杂得多，因为布局需要考虑其他小部件的位置、大小提示和可能的扩展方向，以便正确计算新的几何图形。

from PyQt5 import QtCore, QtGui, QtWidgets

class Square(QtWidgets.QWidget):
    def __init__(self, parent, color):
        super().__init__(parent=parent)
        if color:
            self.color = QtCore.Qt.white
        else:
            self.color = QtCore.Qt.black
        self.setMinimumSize(50, 50)

    def paintEvent(self, event: QtGui.QPaintEvent) -> None:
        painter = QtGui.QPainter(self)
        painter.fillRect(self.rect(), self.color)


class EvenLayout(QtWidgets.QGridLayout):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.setSpacing(0)

    def setGeometry(self, oldRect):
        # assuming that the minimum size is 50 pixel, find the minimum possible
        # "extent" based on the geometry provided
        minSize = max(50 * 8, min(oldRect.width(), oldRect.height()))
        # create a new squared rectangle based on that size
        newRect = QtCore.QRect(0, 0, minSize, minSize)
        # move it to the center of the old one
        newRect.moveCenter(oldRect.center())
        super().setGeometry(newRect)


class Board(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.setSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        layout = EvenLayout(self)
        self.squares = []
        for row in range(8):
            for column in range(8):
                square = Square(self, not (row + column) & 1)
                self.squares.append(square)
                layout.addWidget(square, row, column)


class Chess(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        layout = QtWidgets.QGridLayout(self)
        header = QtWidgets.QLabel('Some {}long label'.format('very ' * 20))
        layout.addWidget(header, 0, 0, 1, 3, QtCore.Qt.AlignCenter)
        self.board = Board()
        layout.addWidget(self.board, 1, 1)

        leftLayout = QtWidgets.QVBoxLayout()
        layout.addLayout(leftLayout, 1, 0)
        rightLayout = QtWidgets.QVBoxLayout()
        layout.addLayout(rightLayout, 1, 2)
        for b in range(1, 9):
            leftLayout.addWidget(QtWidgets.QPushButton('Left Btn {}'.format(b)))
            rightLayout.addWidget(QtWidgets.QPushButton('Right Btn {}'.format(b)))

        footer = QtWidgets.QLabel('Another {}long label'.format('very ' * 18))
        layout.addWidget(footer, 2, 0, 1, 3, QtCore.Qt.AlignCenter)


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Chess()
    w.show()
    sys.exit(app.exec_())

使用图形视图

结果将在视觉上与前一个相同，但虽然整体定位、绘图和交互在概念上会更容易一些，但了解图形视图、场景和对象的工作方式可能需要一些时间来掌握它。

from PyQt5 import QtCore, QtGui, QtWidgets


class Square(QtWidgets.QGraphicsWidget):
    def __init__(self, color):
        super().__init__()
        if color:
            self.color = QtCore.Qt.white
        else:
            self.color = QtCore.Qt.black

    def paint(self, qp, option, widget):
        qp.fillRect(option.rect, self.color)


class Scene(QtWidgets.QGraphicsScene):
    def __init__(self):
        super().__init__()

        self.container = QtWidgets.QGraphicsWidget()
        layout = QtWidgets.QGraphicsGridLayout(self.container)
        layout.setSpacing(0)
        self.container.setContentsMargins(0, 0, 0, 0)
        layout.setContentsMargins(0, 0, 0, 0)
        self.addItem(self.container)
        for row in range(8):
            for column in range(8):
                square = Square(not (row + column) & 1)
                layout.addItem(square, row, column, 1, 1)


class Board(QtWidgets.QGraphicsView):
    def __init__(self):
        super().__init__()
        scene = Scene()
        self.setScene(scene)
        self.setAlignment(QtCore.Qt.AlignCenter)
        # by default a graphics view has a border frame, disable it
        self.setFrameShape(0)
        # make it transparent
        self.setStyleSheet('QGraphicsView {background: transparent;}')

    def resizeEvent(self, event):
        super().resizeEvent(event)
        # zoom the contents keeping the ratio
        self.fitInView(self.scene().container, QtCore.Qt.KeepAspectRatio)


class Chess(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        layout = QtWidgets.QGridLayout(self)
        header = QtWidgets.QLabel('Some {}long label'.format('very ' * 20))
        layout.addWidget(header, 0, 0, 1, 3, QtCore.Qt.AlignCenter)
        self.board = Board()
        layout.addWidget(self.board, 1, 1)

        leftLayout = QtWidgets.QVBoxLayout()
        layout.addLayout(leftLayout, 1, 0)
        rightLayout = QtWidgets.QVBoxLayout()
        layout.addLayout(rightLayout, 1, 2)
        for b in range(1, 9):
            leftLayout.addWidget(QtWidgets.QPushButton('Left Btn {}'.format(b)))
            rightLayout.addWidget(QtWidgets.QPushButton('Right Btn {}'.format(b)))

        footer = QtWidgets.QLabel('Another {}long label'.format('very ' * 18))
        layout.addWidget(footer, 2, 0, 1, 3, QtCore.Qt.AlignCenter)


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Chess()
    w.show()
    sys.exit(app.exec_())