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PyQt - QScrollBar Widget
A scrollbar control enables the user to access parts of the document that is outside the viewable area. It provides visual indicator to the current position. It has a slider by which a value between a preset range is set in analogous fashion. This value is usually correlated to bring a hidden data inside the viewport.
The scrollbar control has four controls −
A slider Two Scroll arrows Page control |
Following signals of QScrollBar class are frequently used −
Sr.No. | Methods & Description |
---|---|
1 |
valueChanged() When the scrollbar’s value changes |
2 |
sliderMoved() When the user drags the slider |
Example
In the following example, three scroll bars are placed to control RGB values of font color for the text displayed in a label. The complete code is as follows −
import sys from PyQt4.QtGui import * from PyQt4.QtCore import * class Example(QWidget): def __init__(self): super(Example, self).__init__() self.initUI() def initUI(self): vbox = QVBoxLayout(self) vbox.addLayout(box) self.setLayout(vbox) hbox = QHBoxLayout() self.l1 = QLabel("Drag scrollbar sliders to change color") self.l1.setFont(QFont("Arial",16)) hbox.addWidget(self.l1) self.s1 = QScrollBar() self.s1.setMaximum(255) self.s1.sliderMoved.connect(self.sliderval) self.s2 = QScrollBar() self.s2.setMaximum(255) self.s2.sliderMoved.connect(self.sliderval) self.s3 = QScrollBar() self.s3.setMaximum(255) self.s3.sliderMoved.connect(self.sliderval) hbox.addWidget(self.s1) hbox.addWidget(self.s2) hbox.addWidget(self.s3) self.setGeometry(300, 300, 300, 200) self.setWindowTitle('QSplitter demo') self.show() def sliderval(self): print self.s1.value(),self.s2.value(), self.s3.value() palette = QPalette() c = QColor(self.s1.value(),self.s2.value(), self.s3.value(),255) palette.setColor(QPalette.Foreground,c) self.l1.setPalette(palette) def main(): app = QApplication(sys.argv) ex = Example() sys.exit(app.exec_()) if __name__ == '__main__': main()
The above code produces the following output −