I am using PyQt5 to build an app with multiple buttons. What I am trying to accomplish is to create a blinking background color (yellow-red) for some of my buttons. btn1.setStyleSheet("background-color: green; color: red; font-weight: 800; font-size: 22") tobyte = 'styleSheet' a = bytearray(tobyte, 'utf-8') animation = QtCore.QPropertyAnimation(' + 'btn' + str(yy) + ', a) animation.setDuration(1000) animation.setLoopCount(1000) animation.setStartValue("background-color: yellow; color: red; font-weight: 800; font-size: 22") animation.setEndValue("background-color: red; color: red; font-weight: 800; font-size: 22") animation.start() The animation starts (it removes the predefined, green background), but it doesn't change the background color of the button to yellow or red. Any ideas? Continue reading...