### 软硬件环境 * windows 10 * PyQt5 * anaconda3 with python 3.6.4 ### 前言 在做界面开发时,无论是移动端的`Android`,还是我们这里讲的`PyQt5`,经常会有一个界面开发准则,那就是`UI`主线程与耗时子线程一定要分开,主线程负责刷新界面,耗时操作,如网络交互、磁盘`IO`等,都应该放在子线程里执行,它们各司其职,保证系统正常运行,提升整体用户体验。 ### 实例代码 首先看下工程目录结构 ![](https://code.xugaoxiang.com/xugaoxiang/blog/raw/master/images/python/pyqt5/proj_skeleton.png) `main.py`,这是工程入口文件,它负责创建`app` ```python # -*- coding: utf-8 -*- """ @author: Xu Gaoxiang @license: Apache V2 @email: djstava@gmail.com @site: https://www.xugaoxiang.com @software: PyCharm @file: main.py @time: 2019/1/10 10:50 """ import sys from PyQt5.QtWidgets import QApplication from gui.mainwindow import MainWindow if __name__ == '__main__': app = QApplication(sys.argv) main_window = MainWindow() main_window.show() sys.exit(app.exec_()) ``` `ui_mainwindow.py`,负责界面的绘制,这个文件通过`designer`图形化工具作图然后使用`pyuic`工具生成对应的`python`代码,可以参考之前的文章 <https://blog.xugaoxiang.com/python/pyqt5-designer.html> ```python # -*- coding: utf-8 -*- # Form implementation generated from reading ui file '.\mainwindow.ui' # # Created by: PyQt5 UI code generator 5.6 # # WARNING! All changes made in this file will be lost! from PyQt5 import QtCore, QtGui, QtWidgets class Ui_MainWindow(object): def setupUi(self, MainWindow): MainWindow.setObjectName("MainWindow") MainWindow.resize(800, 600) MainWindow.setMinimumSize(QtCore.QSize(800, 600)) MainWindow.setMaximumSize(QtCore.QSize(800, 600)) self.centralwidget = QtWidgets.QWidget(MainWindow) self.centralwidget.setObjectName("centralwidget") self.button_ok = QtWidgets.QPushButton(self.centralwidget) self.button_ok.setGeometry(QtCore.QRect(260, 220, 230, 140)) self.button_ok.setMinimumSize(QtCore.QSize(230, 140)) self.button_ok.setMaximumSize(QtCore.QSize(230, 140)) font = QtGui.QFont() font.setPointSize(50) self.button_ok.setFont(font) self.button_ok.setFocusPolicy(QtCore.Qt.TabFocus) self.button_ok.setObjectName("button_ok") MainWindow.setCentralWidget(self.centralwidget) self.statusbar = QtWidgets.QStatusBar(MainWindow) self.statusbar.setObjectName("statusbar") MainWindow.setStatusBar(self.statusbar) self.menubar = QtWidgets.QMenuBar(MainWindow) self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 23)) self.menubar.setObjectName("menubar") self.menuFile = QtWidgets.QMenu(self.menubar) self.menuFile.setObjectName("menuFile") self.menuHelp = QtWidgets.QMenu(self.menubar) self.menuHelp.setObjectName("menuHelp") MainWindow.setMenuBar(self.menubar) self.actionExit = QtWidgets.QAction(MainWindow) self.actionExit.setObjectName("actionExit") self.actionCopy = QtWidgets.QAction(MainWindow) self.actionCopy.setObjectName("actionCopy") self.actionPaste = QtWidgets.QAction(MainWindow) self.actionPaste.setObjectName("actionPaste") self.actionCut = QtWidgets.QAction(MainWindow) self.actionCut.setObjectName("actionCut") self.actionHelp = QtWidgets.QAction(MainWindow) self.actionHelp.setObjectName("actionHelp") self.actionAbout = QtWidgets.QAction(MainWindow) self.actionAbout.setObjectName("actionAbout") self.action_query = QtWidgets.QAction(MainWindow) self.action_query.setObjectName("action_query") self.action_backupDB = QtWidgets.QAction(MainWindow) self.action_backupDB.setObjectName("action_backupDB") self.action_reset_mac = QtWidgets.QAction(MainWindow) self.action_reset_mac.setObjectName("action_reset_mac") self.menuFile.addSeparator() self.menuFile.addAction(self.actionExit) self.menuFile.addSeparator() self.menuHelp.addSeparator() self.menuHelp.addSeparator() self.menuHelp.addAction(self.actionAbout) self.menuHelp.addSeparator() self.menubar.addAction(self.menuFile.menuAction()) self.menubar.addAction(self.menuHelp.menuAction()) self.retranslateUi(MainWindow) QtCore.QMetaObject.connectSlotsByName(MainWindow) def retranslateUi(self, MainWindow): _translate = QtCore.QCoreApplication.translate MainWindow.setWindowTitle(_translate("MainWindow", "分离UI主线程和工作线程")) self.button_ok.setText(_translate("MainWindow", "确定")) self.menuFile.setTitle(_translate("MainWindow", "File")) self.menuHelp.setTitle(_translate("MainWindow", "Help")) self.actionExit.setText(_translate("MainWindow", "退出")) self.actionHelp.setText(_translate("MainWindow", "软件使用说明")) self.actionAbout.setText(_translate("MainWindow", "关于")) ``` `mainwindow.py`,主要负责界面上控件的事件处理 ```python """ @author: Xu Gaoxiang @license: Apache V2 @email: djstava@gmail.com @site: https://www.xugaoxiang.com @software: PyCharm @file: mainwindow.py @time: 2019/1/10 10:49 """ import time from PyQt5.QtWidgets import QMainWindow from gui.ui_mainwindow import * class MainWindow(QMainWindow, Ui_MainWindow): def __init__(self, parent=None): super(MainWindow, self).__init__(parent) self.setupUi(self) # 绑定点击事件 self.button_ok.clicked.connect(self.button_start) def button_start(self): self.button_ok.setChecked(True) self.button_ok.setDisabled(True) time.sleep(20) ``` 这里我们使用`time.sleep(20)`来模拟耗时任务,执行`python main.py`后一会,界面就会出现无响应,假死的现象,等到20秒过后,界面又恢复了正常,用户体验非常差。 ![](https://code.xugaoxiang.com/xugaoxiang/blog/raw/master/images/python/pyqt5/no_responding.png) 其实要解决这个问题,也非常简单。我们将`UI`主线程中的`time.sleep(20)`移动到子线程中就可以了。`PyQt5`中提供了线程类`QThread`,我们继承它并重写它的`run`方法,新建一个新的文件`threads.py` ```python # -*- coding: utf-8 -*- """ @author: Xu Gaoxiang @license: Apache V2 @email: djstava@gmail.com @site: https://www.xugaoxiang.com @software: PyCharm @file: threads.py @time: 2019/1/10 11:03 """ import time from PyQt5.QtCore import QThread, pyqtSignal class WorkThread(QThread): # 使用信号和UI主线程通讯,参数是发送信号时附带参数的数据类型,可以是str、int、list等 finishSignal = pyqtSignal(str) # 带参数示例 def __init__(self, ip, port, parent=None): super(WorkThread, self).__init__(parent) self.ip = ip self.port = port def run(self): ''' 重写 ''' print('=============sleep======ip: {}, port: {}'.format(self.ip, self.port)) time.sleep(20) self.finishSignal.emit('This is a test.') return ``` 注意到这里我们使用了`pyqtSignal`,我们使用它来跟`UI`主线程通讯,一般用于界面元素的刷新,在子线程的最后,我们发送这个信号。 对应的`mainwindow.py`,需要进行如下修改 ```python from gui.threads import WorkThread # 其它部分省略 def button_start(self): print('button_start clicked.') # 设置按钮不可用 self.button_ok.setChecked(True) self.button_ok.setDisabled(True) self.th = WorkThread(ip='192.168.1.1', port=4000) # 将线程th的信号finishSignal和UI主线程中的槽函数button_finish进行连接 self.th.finishSignal.connect(self.button_finish) # 启动线程 self.th.start() def button_finish(self, msg): print('msg: {}'.format(msg)) # 设置按钮可用 self.button_ok.setChecked(False) self.button_ok.setDisabled(False) ``` 一顿操作之后,再次执行`python main.py`,界面就再也不会出现`No Resonding`的提示了,可以在子线程执行过程中可以随意操作界面上的其它控件。 ### 工程源码下载 * <https://github.com/xugaoxiang/learningPyQt5>


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