In this article we will see how to make background of progress bar transparent i.e only the bar of progress bar will be visible and background will be completely transparent. In order to do this we have change the alpha level i.e transparency level to zero which is minimum which makes the background completely invisible. Below is how normal progress bar vs transparent background progress bar looks like 
To change the alpha level we have to change the CSS style sheet of Progress Bar, below is the style sheet.
QProgressBar
{
background-color : rgba(0, 0, 0, 0);
border : 1px;
}
This style sheet code is used with setStyleSheet method below is the implementation.
Python3
# importing librariesfrom PyQt5.QtWidgets import *from PyQt5 import QtCore, QtGuifrom PyQt5.QtGui import *from PyQt5.QtCore import *import sysclass Window(QMainWindow): def __init__(self): super().__init__() # setting title self.setWindowTitle("Python ") # setting background color to window self.setStyleSheet("background-color : yellow") # setting geometry self.setGeometry(100, 100, 600, 400) # calling method self.UiComponents() # showing all the widgets self.show() # method for widgets def UiComponents(self): # creating progress bar bar = QProgressBar(self) # setting geometry to progress bar bar.setGeometry(200, 100, 200, 30) # setting the value bar.setValue(30) # setting alignment to center bar.setAlignment(Qt.AlignCenter) # setting background to invisible bar.setStyleSheet("QProgressBar" "{" "background-color : rgba(0, 0, 0, 0);" "border : 1px" "}")App = QApplication(sys.argv)# create the instance of our Windowwindow = Window()# start the appsys.exit(App.exec()) |
Output : 
