[英]Threading in pyqt4
在我的GUI中,我必须下载很多东西。 我使用urllib来做到这一点。 当然问题就是GUI会冻结,直到下载完所有内容。
我的代码类似于以下内容
QtCore.QObject.connect( self.UI.commandLinkButton_2 , QtCore.SIGNAL("clicked()") , self.addStoryToHistory )
其中上述功能具有下载代码。
没有什么比在这之间发送共享数据更简单,并且该过程仅涉及将数据下载到位置。
什么是不冻结GUI的最简单方法? 我应该使用multiprocessing
还是QThreads
?
任何人都可以指向我一些链接....我不希望它是非常复杂的,所以如果有任何更简单的方法,请指出它....
非常感谢...
这是一个例子,我刚刚从几个月前使用PyQt的http示例作为基础的项目中删除了。 它将从Riverbank网站下载SIP。
它使用来自QtNetwork的QHttp而不是urllib,进度条连接到其dataReadProgress信号。 这应该允许您可靠地下载文件以及具有响应GUI。
from PyQt4.QtCore import QUrl, QFileInfo, QFile, QIODevice
from PyQt4.QtGui import QApplication, QDialog, QProgressBar, QLabel, QPushButton, QDialogButtonBox, \
QVBoxLayout, QMessageBox
from PyQt4.QtNetwork import QHttp
url_to_download = 'http://www.riverbankcomputing.co.uk/static/Downloads/sip4/sip-4.12.3.zip'
class Downloader(QDialog):
def __init__(self, parent=None):
super(Downloader, self).__init__(parent)
self.httpGetId = 0
self.httpRequestAborted = False
self.statusLabel = QLabel('Downloading %s' % url_to_download)
self.closeButton = QPushButton("Close")
self.closeButton.setAutoDefault(False)
self.progressBar = QProgressBar()
buttonBox = QDialogButtonBox()
buttonBox.addButton(self.closeButton, QDialogButtonBox.RejectRole)
self.http = QHttp(self)
self.http.requestFinished.connect(self.httpRequestFinished)
self.http.dataReadProgress.connect(self.updateDataReadProgress)
self.http.responseHeaderReceived.connect(self.readResponseHeader)
self.closeButton.clicked.connect(self.cancelDownload)
mainLayout = QVBoxLayout()
mainLayout.addWidget(self.statusLabel)
mainLayout.addWidget(self.progressBar)
mainLayout.addWidget(buttonBox)
self.setLayout(mainLayout)
self.setWindowTitle('Download Example')
self.downloadFile()
def downloadFile(self):
url = QUrl(url_to_download)
fileInfo = QFileInfo(url.path())
fileName = fileInfo.fileName()
if QFile.exists(fileName):
QFile.remove(fileName)
self.outFile = QFile(fileName)
if not self.outFile.open(QIODevice.WriteOnly):
QMessageBox.information(self, 'Error',
'Unable to save the file %s: %s.' % (fileName, self.outFile.errorString()))
self.outFile = None
return
mode = QHttp.ConnectionModeHttp
port = url.port()
if port == -1:
port = 0
self.http.setHost(url.host(), mode, port)
self.httpRequestAborted = False
path = QUrl.toPercentEncoding(url.path(), "!$&'()*+,;=:@/")
if path:
path = str(path)
else:
path = '/'
# Download the file.
self.httpGetId = self.http.get(path, self.outFile)
def cancelDownload(self):
self.statusLabel.setText("Download canceled.")
self.httpRequestAborted = True
self.http.abort()
self.close()
def httpRequestFinished(self, requestId, error):
if requestId != self.httpGetId:
return
if self.httpRequestAborted:
if self.outFile is not None:
self.outFile.close()
self.outFile.remove()
self.outFile = None
return
self.outFile.close()
if error:
self.outFile.remove()
QMessageBox.information(self, 'Error',
'Download failed: %s.' % self.http.errorString())
self.statusLabel.setText('Done')
def readResponseHeader(self, responseHeader):
# Check for genuine error conditions.
if responseHeader.statusCode() not in (200, 300, 301, 302, 303, 307):
QMessageBox.information(self, 'Error',
'Download failed: %s.' % responseHeader.reasonPhrase())
self.httpRequestAborted = True
self.http.abort()
def updateDataReadProgress(self, bytesRead, totalBytes):
if self.httpRequestAborted:
return
self.progressBar.setMaximum(totalBytes)
self.progressBar.setValue(bytesRead)
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
downloader = Downloader()
downloader.show()
sys.exit(app.exec_())
我建议你改用QNetworkManager并监控下载过程。
请参阅另一个问题: pyQT QNetworkManager和ProgressBars
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