在动画播放的过程中,要保证对象的存在,即:self.animation创建的对象;

如果使用如下方式,动画将会异常,被释放掉了:

class MyButton(QPushButton):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._opacity = 0.0

        # 1.创建动画
        animation = QPropertyAnimation(self, b'opacity')
        animation.setDuration(1000)
        animation.setStartValue(0.0)
        animation.setEndValue(0.9)
        animation.setLoopCount(-1)
        animation.start()

    @pyqtProperty(float)
    def opacity(self):
        return self._opacity
    
    @opacity.setter
    def opacity(self, opacity) -> None: 
        self._opacity = opacity
        t = f'background-color: rgba(0, 0, 0, {opacity})'
        self.setStyleSheet(t)

正确的方式如下:

import sys  
from PyQt5.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget  ,QPushButton
from PyQt5.QtGui import QPixmap, QPainter, QBrush, QPen, QColor  
from PyQt5.QtCore import QPropertyAnimation, Qt  ,QEasingCurve,QPoint,pyqtProperty
  

class MyButton(QPushButton):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._opacity = 0.0

        # 1.创建动画
        self.animation = QPropertyAnimation(self, b'opacity')
        self.animation.setDuration(1000)
        self.animation.setStartValue(0.0)
        self.animation.setEndValue(0.9)
        self.animation.setLoopCount(-1)
        self.animation.start()

    @pyqtProperty(float)
    def opacity(self):
        return self._opacity
    
    @opacity.setter
    def opacity(self, opacity) -> None: 
        self._opacity = opacity
        t = f'background-color: rgba(0, 0, 0, {opacity})'
        self.setStyleSheet(t)
class Window(QWidget):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.setWindowTitle('使用插值')
        self.resize(500, 500)
        self.move(400, 200)
        self.setStyleSheet("background-color: red;") 
        self.btn = MyButton(self)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())