FTP 下载带有显示当前下载状态的文本标签

Question

我制作了一个 GUI，在其中单击 “下载” 按钮后，程序将从 FTP 服务器下载文件。这样做时，我希望标签更新，例如："Connecting..." -> "Downloading..." -> “已下载！” 我试着用线程模块来做，但它似乎不起作用：

def updater(self):
    self.updateStatusText.setText("Status: Connecting...")

    thread = threading.Thread(target=self.download)
    thread.start()

    while thread.isAlive():
        self.updateStatusText.setText("Status: Still Downloading...")


def download(self):
    ftp = FTP('testdomain.com')
    ftp.login(user='username', passwd='password')

    ftp.cwd('/main_directory/')

    filename = 'testfile.bin'

    with open(filename, 'wb') as localfile:
        ftp.retrbinary('RETR ' + filename, localfile.write, 1024)

    ftp.quit()
    localfile.close()

它只是下载文件，根本不改变文本标签。我必须在这里使用 QThread 吗？我也尝试使用 asyncio 但等待 self.updateStatusText.setText("Connecting...") 似乎 return None 并且我得到 TypeError...

Answer 1

应执行以下代码：

class DownloadThread(QtCore.QThread):

    data_downloaded = QtCore.pyqtSignal(object)

    def run(self):
        self.data_downloaded.emit('Connecting...')

        ftp = FTP('example.com')
        ftp.login(user='user', passwd='password')

        ftp.cwd('/main_directory/')

        self.data_downloaded.emit('Downloading...')

        filename = 'testfile.bin'
        with open(filename, 'wb') as localfile:
            ftp.retrbinary('RETR ' + filename, localfile.write)

        ftp.quit()

        self.data_downloaded.emit('Done')

class MainWindow(QtGui.QWidget):
    def __init__(self):
        super(MainWindow, self).__init__()
        self.label = QtGui.QLabel
        self.button = QtGui.QPushButton("Start")
        self.button.clicked.connect(self.start_download)
        layout = QtGui.QVBoxLayout()
        layout.addWidget(self.button)
        layout.addWidget(self.label)
        self.setLayout(layout)

    def start_download(self):
        self.thread = DownloadThread()
        self.thread.data_downloaded.connect(self.on_data_ready)
        self.thread.start()

    def on_data_ready(self, data):
        self.label.setText(unicode(data))

基于：Updating GUI elements in MultiThreaded PyQT.

你的后续问题：

FTP 下载带有显示当前下载状态的文本标签

FTP download with text label showing the current status of the download

python

ftp

pyqt

ftplib

python-3.x