PyQt5让QScrollArea支持鼠标拖动操作

#!/usr/bin/evn python3# -*- coding: utf-8 -*-import sysfrom PyQt5.QtWidgets import (QApplication, QWidget, QScrollArea, QLabel)from PyQt5.QtCore import QEventclass TestWindow(QWidget):def __init__(self):super(TestWindow, self).__init__()self.resize(800, 600)self.move(0, 0)# self.setMouseTracking(False)self.last_time_move = 0self.initUI()def initUI(self):self.central_widget = QWidget(self)self.scroll_area = QScrollArea(self)self.scroll_area.setGeometry(0, 0, 400, 400)self.scroll_area.setWidgetResizable(True)self.scroll_bar = self.scroll_area.verticalScrollBar()self.scroll_contents = QWidget()self.scroll_contents.setGeometry(0, 0, 400, 800)self.scroll_contents.setMinimumSize(380, 1000)self.label_1 = QLabel(self.scroll_contents)self.label_1.move(50, 100)self.label_1.setText("HelloRyan")self.label_2 = QLabel(self.scroll_contents)self.label_2.move(50, 200)self.label_2.setText("你好")self.label_3 = QLabel(self.scroll_contents)self.label_3.move(50, 300)self.label_3.setText("-----------")self.label_4 = QLabel(self.scroll_contents)self.label_4.move(50, 400)self.label_4.setText("542543255235432543252")self.label_5 = QLabel(self.scroll_contents)self.label_5.move(50, 500)self.label_5.setText("5432543262542")self.label_6 = QLabel(self.scroll_contents)self.label_6.move(50, 600)self.label_6.setText("4325432532")self.scroll_area.setWidget(self.scroll_contents)self.scroll_area.installEventFilter(self)# def mouseMoveEvent(self, event):# if event.pos().x() > 0 and event.pos().x() < 400 and event.pos().y() > 0 and event.pos().y() < 400:# if self.last_time_move == 0:# self.last_time_move = event.pos().y()## distance = self.last_time_move - event.pos().y()# self.scroll_bar.setValue(self.scroll_bar.value() + distance)## self.last_time_move = event.pos().y()# print("move%d" % event.pos().y())## def mouseReleaseEvent(self, event):# self.last_time_move = 0# print("up")def eventFilter(self, source, event):if event.type() == QEvent.MouseMove:print(event.pos().y())if self.last_time_move == 0:self.last_time_move = event.pos().y()distance = self.last_time_move - event.pos().y()self.scroll_bar.setValue(self.scroll_bar.value() + distance)self.last_time_move = event.pos().y()elif event.type() == QEvent.MouseButtonRelease:self.last_time_move = 0return QWidget.eventFilter(self, source, event)if __name__ == "__main__":app = QApplication(sys.argv)test = TestWindow()test.show()sys.exit(app.exec_())