PyQT:在窗口中获取实时打印输出

Question

我正在开发一个GUI，用于在按下"my_button"按钮时调用函数"my_function"。

此函数以迭代方式处理数据。它包含一个"for"循环，在每次迭代时，它都会打印出一条消息，显示我的函数的进度。我希望这些打印件实时显示在我的 GUI 中(在本例中为文本编辑小部件(。我该怎么做？

我想明确表示，我需要实时显示。我在网上找到了一些解决方案，但所有打印仅在函数完成执行时才出现。我需要实时显示打印件，以便欣赏功能进度。提前感谢您的提示！

这是一个最小的可复制示例(我通过qt设计器获得了模板(：

class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(163, 225)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.formLayout = QtWidgets.QFormLayout(self.centralwidget)
self.formLayout.setObjectName("formLayout")
self.my_button = QtWidgets.QPushButton(self.centralwidget)
self.my_button.setObjectName("my_button")
self.formLayout.setWidget(0, QtWidgets.QFormLayout.LabelRole, self.my_button)
self.textEdit = QtWidgets.QTextEdit(self.centralwidget)
self.textEdit.setObjectName("textEdit")
self.formLayout.setWidget(1, QtWidgets.QFormLayout.SpanningRole, self.textEdit)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 163, 22))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
self.my_button.clicked.connect(self.my_function)
def my_function(self):
for idx in range(10):
print('Executing iteration '+str(idx)+' ...')
time.sleep(1) # replaces time-consuming task
print('Finished!')
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.my_button.setText(_translate("MainWindow", "Execute"))

if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())

Answer 1

Qt的黄金法则：你不应该执行在GUI的主线程中消耗大量时间的任务，因为它们会阻塞Qt的事件循环。

考虑到上述情况，您必须在另一个线程中执行耗时的任务，并通过信号将信息发送到 GUI 线程。

另一方面，你不应该修改Qt Designer生成的类，而是创建另一个从适当的小部件继承的类，并用初始类填充。

import threading
import time
from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(163, 225)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.formLayout = QtWidgets.QFormLayout(self.centralwidget)
self.formLayout.setObjectName("formLayout")
self.my_button = QtWidgets.QPushButton(self.centralwidget)
self.my_button.setObjectName("my_button")
self.formLayout.setWidget(0, QtWidgets.QFormLayout.LabelRole, self.my_button)
self.textEdit = QtWidgets.QTextEdit(self.centralwidget)
self.textEdit.setObjectName("textEdit")
self.formLayout.setWidget(1, QtWidgets.QFormLayout.SpanningRole, self.textEdit)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 163, 22))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.my_button.setText(_translate("MainWindow", "Execute"))

class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
valueChanged = QtCore.pyqtSignal(int)
def __init__(self, parent=None):
super().__init__(parent)
self.setupUi(self)
self.valueChanged.connect(self.on_value_changed)
self.my_button.clicked.connect(self.on_clicked)
@QtCore.pyqtSlot()
def on_clicked(self):
threading.Thread(target=self.my_function, daemon=True).start()
@QtCore.pyqtSlot(int)
def on_value_changed(self, value):
self.textEdit.append("Value: {}".format(value))
def my_function(self):
for idx in range(10):
self.valueChanged.emit(idx)
print("Executing iteration " + str(idx) + " ...")
time.sleep(1)  # replaces time-consuming task
print("Finished!")

if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())