python - PyQt5-为什么进度条没有显示文件复制进度？

我正在尝试使用PyQt5中包含的进度条复制文件。我可以在带有print("Copied: {}".format(percent))的控制台中看到复制了100％。

但是，进度条不会更新我的复制过程。如何检查信号是否已发送？我在哪里弄错了？

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_())

最佳答案

好的，我知道了。线程支持的类中必须有一个run方法，当您在实例对象start()上调用self.ext方法时将执行该方法。我还添加了self.ext.join()方法，以便在执行和完成线程之前不结束程序。

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。

关于python - PyQt5-为什么进度条没有显示文件复制进度？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/45372328/