PyQt5 - 为什么进度条不显示文件复制进度?

Question

我正在尝试复制一个带有 PyQt5 中包含的进度条的文件。我可以在带有print("Copied: {}".format(percent))的控制台中看到 100% 被复制。

但是，我的进度条不会更新我的复制过程。如何检查信号是否已发送？我哪里犯了错误？

import os, sys
from PyQt5 import QtWidgets, QtCore
class Extended(QtCore.QThread):
def __init__(self):
super().__init__()
self.src_file = 'test.txt'
self.dst_file = 'test_copy.txt'
self.copyfileobj(self.src_file, self.dst_file, self.cb)
copied_percent = QtCore.pyqtSignal(int)
def cb(self, temp_file_size):
self.file_size = os.stat(self.src_file).st_size
percent = int(temp_file_size/self.file_size*100)
print("Copied: {}".format(percent))
self.copied_percent.emit(percent)
def copyfileobj(self, fsrc, fdst, callback, length=16*1024):
copied = 0
with open(fsrc, "rb") as fr, open(fdst, "wb") as fw:
while True:
buff = fr.read(length)
if not buff:
break
fw.write(buff)
copied += len(buff)
callback(copied)

class MyApp(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
self.w = QtWidgets.QWidget()
self.w.setWindowTitle("Progress bar copy test")
# Add widgets on the window
self.copy_button = QtWidgets.QPushButton("Copy", self)
self.copy_button.sizeHint()
self.progress_bar = QtWidgets.QProgressBar(self)
self.progress_bar.setGeometry(0, 40, 300, 25)
self.progress_bar.setMaximum(100)
self.copy_button.clicked.connect(self.on_button_click)
def on_button_click(self):
self.copy_button.setDisabled(True)
self.ext = Extended()
self.ext.copied_percent.connect(self.on_count_change)
self.ext.start()
def on_count_change(self, value):
self.progress_bar.setValue(value)

if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
prog = MyApp()
prog.show()
sys.exit(app.exec_())

Answer 1

好的，我想通了。线程支持的类中必须有一个run方法，当您在实例对象上调用start()方法时self.ext执行该方法。我还添加了self.ext.join()方法，以便在线程执行和完成之前不结束程序。

import os, sys
from PyQt5 import QtWidgets, QtCore

class Extended(QtCore.QThread):
"""
For running copy operation
"""
copied_percent_signal= QtCore.pyqtSignal(int)
def __init__(self):
super().__init__()
self.src_file = 'test.txt'
self.dst_file = 'test_copy.txt'
self.file_size = os.stat(self.src_file).st_size
def run(self):
self.copyfileobj(self.src_file, self.dst_file, self.my_callback)
def my_callback(self, temp_file_size):
percent = int(temp_file_size/self.file_size*100)
print("Copiedd: {}".format(percent))
self.copied_percent_signal.emit(percent)
def copyfileobj(self, fsrc, fdst, callback, length=16*1024):
copied = 0
with open(fsrc, "rb") as fr, open(fdst, "wb") as fw:
while True:
buff = fr.read(length)
if not buff:
break
fw.write(buff)
copied += len(buff)
callback(copied)

class MyApp(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
# Instance attribute defined later in on_button_click()
self.ext = None
self.w = QtWidgets.QWidget()
self.w.setWindowTitle("Progress bar copy test")
# Add widgets on the window
self.copy_button = QtWidgets.QPushButton("Copy", self)
self.copy_button.sizeHint()
self.progress_bar = QtWidgets.QProgressBar(self)
self.progress_bar.setGeometry(0, 40, 300, 25)
self.progress_bar.setMaximum(100)
self.copy_button.clicked.connect(self.on_button_click)
def on_button_click(self):
self.copy_button.setDisabled(True)
self.ext = Extended()
self.ext.copied_percent_signal.connect(self.on_count_change)
self.ext.start()
self.ext.join()
def on_count_change(self, value):
self.progress_bar.setValue(value)

if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
prog = MyApp()
prog.show()
sys.exit(app.exec_())

我的文件正在复制，进度条正在工作。