In this article we will see how we can get the range changed signal of QScrollBar. QScrollBar is a control that enables the user to access parts of a document that is larger than the widget used to display it. Slider is the scroll-able object inside the bar. By default value range from 0 to 99. Value is basically depend upon the slider position, scroll bar value changes according to the position of the slider, value increases when slider goes down and decreases when slider moves up. It can be programmatically set with the help of setValue method. Range is basically a combination of minimum and maximum value which can be set with the help of setRange method. This signal is emitted when the slider range has changed, with min being the new minimum, and max being the new maximum.
In order to do this we will use rangeChanged method with the scroll bar object. Syntax : scroll.rangeChanged.connect(method) Argument : It takes method as argument Return : It returns None
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 geometry self.setGeometry(100, 100, 500, 400) # calling method self.UiComponents() # showing all the widgets self.show() # method for components def UiComponents(self): scroll = QScrollBar(self) # setting geometry of the scroll bar scroll.setGeometry(100, 50, 30, 200) # making its background color to green scroll.setStyleSheet("background : lightgrey;") # creating a label label = QLabel("neveropen", self) # setting geometry to the label label.setGeometry(200, 100, 300, 80) # making label multi line label.setWordWrap(True) # getting range changed signal scroll.rangeChanged.connect(lambda: do_action()) # method called when signal is emitted def do_action(): # setting text to the label label.setText("Range Changed Signal Emitted") # setting range of scroll bar scroll.setRange(200, 250)# create pyqt5 appApp = QApplication(sys.argv)# create the instance of our Windowwindow = Window()# start the appsys.exit(App.exec()) |
Output : 
