pyqt信号槽

import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QWidget, QLCDNumber, QSlider,
                             QVBoxLayout, QApplication)


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        lcd = QLCDNumber(self)
        sld = QSlider(Qt.Horizontal, self)

        vbox = QVBoxLayout()
        vbox.addWidget(lcd)
        vbox.addWidget(sld)

        self.setLayout(vbox)
        #将滚动条的valueChanged信号连接到lcd的display插槽。
        sld.valueChanged.connect(lcd.display)

        self.setGeometry(300, 300, 250, 150)
        self.setWindowTitle('Signal & slot')
        self.show()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())