PySide2下利用QThread实现后台线程
PySide2简介
PySide2是Qt官方的Qt for Python Project的实现，支持Qt 5.12+。
安装方式：
pip3 install PySide2
同时还会安装：
- pyside2-designer：设计师工具
- pyside2-lupdate：国际化工具
- pyside2-rcc：资源工具
- pyside2-uic：ui文件编译成python工具
上述命令可以直接在命令行下执行。
界面
使用pyside2-designer设计界面：
设计界面
保存为：ui_widget.ui
Widget
0
0
350
250
Widget
-
-
-
0
true
false
-
-
start
-
cancel
执行命令：
pyside2-uic -o ui_widget.py ui_widget.ui
生成对应的python文件ui_widget.py：
# -*- coding: utf-8 -*-
################################################################################
## Form generated from reading UI file 'widget.ui'
##
## Created by: Qt User Interface Compiler version 5.15.2
##
## WARNING! All changes made in this file will be lost when recompiling UI file!
################################################################################
from PySide2.QtCore import *
from PySide2.QtGui import *
from PySide2.QtWidgets import *
class Ui_Widget(object):
def setupUi(self, Widget):
if not Widget.objectName():
Widget.setObjectName(u"Widget")
Widget.resize(350, 250)
self.verticalLayout_2 = QVBoxLayout(Widget)
self.verticalLayout_2.setObjectName(u"verticalLayout_2")
self.lcdNumber = QLCDNumber(Widget)
self.lcdNumber.setObjectName(u"lcdNumber")
self.verticalLayout_2.addWidget(self.lcdNumber)
self.verticalLayout = QVBoxLayout()
self.verticalLayout.setObjectName(u"verticalLayout")
self.progressBar = QProgressBar(Widget)
self.progressBar.setObjectName(u"progressBar")
self.progressBar.setValue(0)
self.progressBar.setTextVisible(True)
self.progressBar.setInvertedAppearance(False)
self.verticalLayout.addWidget(self.progressBar)
self.horizontalLayout = QHBoxLayout()
self.horizontalLayout.setObjectName(u"horizontalLayout")
self.btnStart = QPushButton(Widget)
self.btnStart.setObjectName(u"btnStart")
self.horizontalLayout.addWidget(self.btnStart)
self.btnCancel = QPushButton(Widget)
self.btnCancel.setObjectName(u"btnCancel")
self.horizontalLayout.addWidget(self.btnCancel)
self.verticalLayout.addLayout(self.horizontalLayout)
self.verticalLayout_2.addLayout(self.verticalLayout)
self.retranslateUi(Widget)
QMetaObject.connectSlotsByName(Widget)
# setupUi
def retranslateUi(self, Widget):
Widget.setWindowTitle(QCoreApplication.translate("Widget", u"Widget", None))
self.btnStart.setText(QCoreApplication.translate("Widget", u"start", None))
self.btnCancel.setText(QCoreApplication.translate("Widget", u"cancel", None))
# retranslateUi
逻辑
编写文件backgroundworker.py：
# -*- coding: utf-8 -*-
from PySide2.QtCore import QObject, Signal, qDebug, QThread, Slot
class BackgroundWorker(QObject):
report_progress = Signal(int)
finished = Signal(int)
def __init__(self, parent=None):
super().__init__(parent)
self.is_cancelled_ = False
self.progress_ = 0
@Slot()
def run(self):
qDebug('start...thread id: '+str(QThread.currentThread()))
for _ in range(10):
if (self.is_cancelled_):
break
QThread.msleep(1000)
self.progress_ += 10
self.report_progress.emit(self.progress_)
self.finished.emit(self.progress_)
self.reset()
def cancel(self):
self.is_cancelled_ = True
qDebug('cancelled...thread id: '+str(QThread.currentThread()))
def reset(self):
self.is_cancelled_ = False
self.progress_ = 0
编写文件widget.py：
# -*- coding: utf-8 -*-
from PySide2.QtCore import QThread, QTime, Signal, Slot, qDebug, QTimer
from PySide2.QtWidgets import QMessageBox, QWidget
from ui_widget import Ui_Widget
from backgroundworker import BackgroundWorker
class Widget(QWidget):
start_background_work = Signal()
def __init__(self, parent=None):
super().__init__(parent)
self.ui = Ui_Widget()
self.ui.setupUi(self)
self.ui.btnCancel.setDisabled(True)
self.ui.progressBar.setRange(0, 100)
self.ui.progressBar.setValue(0)
self.ui.lcdNumber.setDigitCount(8)
self.background_worker_thread_ = QThread()
self.background_worker_ = BackgroundWorker()
self.background_worker_.moveToThread(self.background_worker_thread_)
self.timer_ = QTimer()
self.start_background_work.connect(self.background_worker_.run)
self.background_worker_.report_progress.connect(self.show_progress)
self.background_worker_.finished.connect(self.show_result)
self.timer_.timeout.connect(lambda: self.ui.lcdNumber.display(
QTime.currentTime().toString('hh:mm:ss')))
self.timer_.start(1000)
@Slot()
def on_btnStart_clicked(self):
if not self.background_worker_thread_.isRunning():
self.background_worker_thread_.start()
self.ui.btnStart.setDisabled(True)
self.ui.btnCancel.setDisabled(False)
self.start_background_work.emit()
qDebug('start button was clicked! thread id: ' +
str(QThread.currentThread()))
@Slot()
def on_btnCancel_clicked(self):
qDebug('cancel button was clicked! thread id: ' +
str(QThread.currentThread()))
self.background_worker_.cancel()
@Slot()
def show_progress(self, progress):
qDebug('show progress. thread id: '+str(QThread.currentThread()))
self.ui.progressBar.setValue(progress)
@Slot()
def show_result(self, complete_progress):
qDebug('show result. thread id: '+str(QThread.currentThread()))
QMessageBox.information(
self, 'result', '%d%% completed!' % complete_progress)
self.ui.btnStart.setDisabled(False)
self.ui.btnCancel.setDisabled(True)
self.ui.progressBar.setValue(0)
def closeEvent(self, event):
qDebug('close')
if self.background_worker_thread_.isRunning():
self.background_worker_.cancel()
self.background_worker_thread_.quit()
self.background_worker_thread_.wait()
if self.timer_.isActive():
self.timer_.stop()
return super().closeEvent(event)
编写文件main.py：
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import sys
from PySide2.QtWidgets import QApplication
from widget import Widget
if __name__ == '__main__':
app = QApplication(sys.argv)
widget = Widget()
widget.show()
sys.exit(app.exec_())
运行：python3 main.py
结果
开始
正常结束
中途结束