Pyqt5：进度条直到作业完成才渲染

Question

我正在尝试制作一个用于复制大文件的进度条。但是，当前对话框窗口变黑，直到该过程完成。现在，我了解到我可能必须学习如何使用踏步并将数据传递回GUI。但是我仍然不明白为什么窗口无法完全渲染。我知道窗口是否没有响应，因为moveFilesWithProgress函数正在运行。但是在该函数中，我正在更新进度条值。我什至尝试添加QtGui.QGuiApplication.processEvents()，希望它会在继续迭代之前更新gui。

如果不使用多线程进程就可以解决此问题，我将不胜感激，但如果无法解决，我将非常感谢您使用Qthread的简单示例。我发现了一个相关的问题，但是要理解该示例还有很多事情要做。 here is the link

示例代码：

#!/usr/bin/env python
import os
import sys
import shutil
from PyQt5.QtWidgets import (QApplication, QDialog, QLineEdit, QMainWindow,
                            QPushButton, QProgressBar)
import PyQt5.QtGui as QtGui

class MainWindow(QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()
        self.button = QPushButton("Copy", self)
        self.button.clicked.connect(self.archiveEntry)
        self.show()

    def archiveEntry(self):
        self.p = ProgressBar()
        self.p.show()
        Dir = "/media/zachlab/Windows/LinuxStorage/old/embryos"
        outDir = "/media/zachlab/Windows/LinuxStorage/old/out"
        run = self.p.moveFilesWithProgress(Dir, outDir)
        # if run:
        #    self.p.close


class ProgressBar(QDialog):
    def __init__(self):
        super().__init__()
        self.pbar = QProgressBar(self)

    def timerEvent(self, e):
        if self.step >= 100:
            self.timer.stop()
            self.btn.setText('Finished')
            return
        self.pbar.setValue(self.step)

    def update(self, value):
        self.pbar.setValue(value)
        QtGui.QGuiApplication.processEvents()

    def calculateAndUpdate(self, done, total):
        progress = int(round((done / float(total)) * 100))
        self.update(progress)


    def countFiles(self, directory):
        files = []
        if os.path.isdir(directory):
            for path, dirs, filenames in os.walk(directory):
                files.extend(filenames)
        return len(files)

    def makedirs(self, dest):
        if not os.path.exists(dest):
            os.makedirs(dest)

    def moveFilesWithProgress(self, src, dest):
        numFiles = self.countFiles(src)
        if os.path.exists(dest):
            return 0
        if numFiles > 0:
            self.makedirs(dest)
            numCopied = 0

            for path, dirs, filenames in os.walk(src):
                for directory in dirs:
                    destDir = path.replace(src, dest)
                    self.makedirs(os.path.join(destDir, directory))

                for sfile in filenames:
                    srcFile = os.path.join(path, sfile)
                    destFile = os.path.join(path.replace(src, dest), sfile)
                    shutil.copy(srcFile, destFile)
                    numCopied += 1
                    self.calculateAndUpdate(numCopied, numFiles)
                    self.show()
            return 1
        else:
            return 0


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = MainWindow()
    sys.exit(app.exec_())

Answer 1

繁重的任务不应在主线程上运行，而应使用线程。在这种情况下，我已替换了您的逻辑，因此有一个类负责复制通过进度，错误等迹象通知的文件。该类的对象将驻留在另一个线程中，该线程通过信号通知GUI。情况下，我将使用QProgressDialog来显示进度。

#!/usr/bin/env python
import os
import sys
import shutil
import threading
from PyQt5 import QtCore, QtGui, QtWidgets

class MainWindow(QtWidgets.QMainWindow):
    startMoveFilesSignal = QtCore.pyqtSignal(str, str)

    def __init__(self):
        super(MainWindow, self).__init__()
        srcdir = "/media/zachlab/Windows/LinuxStorage/old/embryos"
        dstdir = "/media/zachlab/Windows/LinuxStorage/old/out"
        self.le_src = QtWidgets.QLineEdit(srcdir)
        self.le_dst = QtWidgets.QLineEdit(dstdir)
        self.button = QtWidgets.QPushButton("Copy")
        self.button.clicked.connect(self.archiveEntry)

        central_widget = QtWidgets.QWidget()
        self.setCentralWidget(central_widget)
        lay = QtWidgets.QFormLayout(central_widget)
        lay.addRow("From: ", self.le_src)
        lay.addRow("To: ", self.le_dst)
        lay.addRow(self.button)

        self.progressbar = QtWidgets.QProgressDialog(self)
        self.progressbar.hide()

        thread = QtCore.QThread(self)
        thread.start()
        self.helper = MoveFileHelper()
        self.startMoveFilesSignal.connect(self.helper.moveFilesWithProgress)
        self.helper.progressChanged.connect(self.progressbar.setValue)
        self.helper.finished.connect(self.on_finished)
        self.helper.started.connect(self.progressbar.show)
        self.helper.errorOccurred.connect(self.on_errorOcurred)
        self.helper.moveToThread(thread)

    @QtCore.pyqtSlot()
    def archiveEntry(self):
        self.startMoveFilesSignal.emit(self.le_src.text(), self.le_dst.text())
        self.progressbar.hide()

    @QtCore.pyqtSlot()
    def on_finished(self):
        self.button.setText('Finished')

    @QtCore.pyqtSlot(str)
    def on_errorOcurred(self, msg):
        QtWidgets.QMessageBox.critical(self, "Error Ocurred", msg)

class MoveFileHelper(QtCore.QObject):
    progressChanged = QtCore.pyqtSignal(int)
    started = QtCore.pyqtSignal()
    finished = QtCore.pyqtSignal()
    errorOccurred = QtCore.pyqtSignal(str)

    def calculateAndUpdate(self, done, total):
        progress = int(round((done / float(total)) * 100))
        self.progressChanged.emit(progress)

    @staticmethod
    def countFiles(directory):
        count = 0
        if os.path.isdir(directory):
            for path, dirs, filenames in os.walk(directory):
                count += len(filenames)
        return count

    @staticmethod
    def makedirs(dest):
        if not os.path.exists(dest):
            os.makedirs(dest)

    @QtCore.pyqtSlot(str, str)
    def moveFilesWithProgress(self, src, dest):
        numFiles = MoveFileHelper.countFiles(src)
        if os.path.exists(dest):
            self.errorOccurred.emit("Dest exist")
            return 
        if numFiles > 0:
            self.started.emit()
            MoveFileHelper.makedirs(dest)
            numCopied = 0
            for path, dirs, filenames in os.walk(src):
                for directory in dirs:
                    destDir = path.replace(src, dest)
                    MoveFileHelper.makedirs(os.path.join(destDir, directory))

                for sfile in filenames:
                    srcFile = os.path.join(path, sfile)
                    destFile = os.path.join(path.replace(src, dest), sfile)
                    shutil.copy(srcFile, destFile)
                    numCopied += 1
                    self.calculateAndUpdate(numCopied, numFiles)
            self.finished.emit()

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    ex = MainWindow()
    ex.resize(640, ex.sizeHint().height())
    ex.show()
    sys.exit(app.exec_())