PyQt5 QScrollBar – 获取范围改变信号

在本文中，我们将了解如何获取 QScrollBar 的范围变化信号。 QScrollBar 是一个控件，它使用户能够访问大于用于显示它的小部件的文档部分。 Slider 是栏内的可滚动对象。默认值范围是 0 到 99。值基本上取决于滑块的位置，滚动条的值根据滑块的位置而变化，滑块下降时值增加，滑块上升时值减小。它可以在setValue方法的帮助下以编程方式设置。范围基本上是最小值和最大值的组合，可以借助setRange方法设置。当滑块范围发生变化时会发出此信号，min 是新的最小值，max 是新的最大值。

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

编程需要懂一点英语

下面是实现

# importing libraries
from PyQt5.QtWidgets import * 
from PyQt5 import QtCore, QtGui
from PyQt5.QtGui import * 
from PyQt5.QtCore import * 
import sys
  
  
class 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("GeesforGeeks", 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 app
App = QApplication(sys.argv)
  
# create the instance of our Window
window = Window()
  
# start the app
sys.exit(App.exec())

输出：