如何在Qt Designer中创建切换开关按钮？

Qt Designer可以在窗口中设置位置并初始化窗口小部件的某些属性，但是创建带有自定义绘制为开关的窗口小部件并不起作用，因此必须使用python来实现。很久以前，为一个项目实现一个开关，这样它将显示该代码：

from PyQt5.QtCore import QObject, QSize, QPointF, QPropertyAnimation, QEasingCurve, pyqtProperty, pyqtSlot, Qt
from PyQt5.QtGui import  QPainter, QPalette, QLinearGradient, QGradient
from PyQt5.QtWidgets import QAbstractButton, QApplication, QWidget, QHBoxLayout, QLabel


class SwitchPrivate(QObject):
    def __init__(self, q, parent=None):
        QObject.__init__(self, parent=parent)
        self.mPointer = q
        self.mPosition = 0.0
        self.mGradient = QLinearGradient()
        self.mGradient.setSpread(QGradient.PadSpread)

        self.animation = QPropertyAnimation(self)
        self.animation.setTargetObject(self)
        self.animation.setPropertyName(b'position')
        self.animation.setStartValue(0.0)
        self.animation.setEndValue(1.0)
        self.animation.setDuration(200)
        self.animation.setEasingCurve(QEasingCurve.InOutExpo)

        self.animation.finished.connect(self.mPointer.update)

    @pyqtProperty(float)
    def position(self):
        return self.mPosition

    @position.setter
    def position(self, value):
        self.mPosition = value
        self.mPointer.update()

    def draw(self, painter):
        r = self.mPointer.rect()
        margin = r.height()/10
        shadow = self.mPointer.palette().color(QPalette.Dark)
        light = self.mPointer.palette().color(QPalette.Light)
        button = self.mPointer.palette().color(QPalette.Button)
        painter.setPen(Qt.NoPen)

        self.mGradient.setColorAt(0, shadow.darker(130))
        self.mGradient.setColorAt(1, light.darker(130))
        self.mGradient.setStart(0, r.height())
        self.mGradient.setFinalStop(0, 0)
        painter.setBrush(self.mGradient)
        painter.drawRoundedRect(r, r.height()/2, r.height()/2)

        self.mGradient.setColorAt(0, shadow.darker(140))
        self.mGradient.setColorAt(1, light.darker(160))
        self.mGradient.setStart(0, 0)
        self.mGradient.setFinalStop(0, r.height())
        painter.setBrush(self.mGradient)
        painter.drawRoundedRect(r.adjusted(margin, margin, -margin, -margin), r.height()/2, r.height()/2)

        self.mGradient.setColorAt(0, button.darker(130))
        self.mGradient.setColorAt(1, button)

        painter.setBrush(self.mGradient)

        x = r.height()/2.0 + self.mPosition*(r.width()-r.height())
        painter.drawEllipse(QPointF(x, r.height()/2), r.height()/2-margin, r.height()/2-margin)

    @pyqtSlot(bool, name='animate')
    def animate(self, checked):
        self.animation.setDirection(QPropertyAnimation.Forward if checked else QPropertyAnimation.Backward)
        self.animation.start()


class Switch(QAbstractButton):
    def __init__(self, parent=None):
        QAbstractButton.__init__(self, parent=parent)
        self.dPtr = SwitchPrivate(self)
        self.setCheckable(True)
        self.clicked.connect(self.dPtr.animate)

    def sizeHint(self):
        return QSize(84, 42)

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        self.dPtr.draw(painter)

    def resizeEvent(self, event):
        self.update()


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

注意： Qt的世界中的另一种可能的解决方案是使用QML开关₁，₂组分。

注意：在本文中，我指出了如何将自定义窗口小部件添加到.ui文件。