从子程序到 pyQT Widget 的标准输出的实时输出

问题描述

您好，我已经看到关于这个问题已经有很多问题了，但是似乎没有一个回答我的问题.

Hi I have seen there are already many questions on this issue however none of them seems to answer my query .

根据下面的链接，我什至在使用 windows 时尝试了 winpexpect，但它似乎对我有用.从 ffmpeg 获取实时输出到用于进度条(PyQt4，stdout)

As per below link i even tried winpexpect as i am using windows , however it dosent seems to e working for me . Getting realtime output from ffmpeg to be used in progress bar (PyQt4, stdout)

我正在使用 subprocess.Popen 运行一个子程序，并希望在 pyQt Widget 中查看实时结果.目前它在 pyQt 小部件中显示结果，但仅在子命令完成执行之后.我需要知道是否有一种方法可以将子进程的输出实时获取到窗口中.请参阅下面的代码，我尝试了所有这些.

I am running a subprogram with subprocess.Popen and want to see the real time result in a pyQt Widget. Currently it shows the result in the pyQt widget but only after the sub command is finished executing . I need to know if there s a way when we can get the output from a subprocess at real time into the window . See the code below which i tried for all this .

import sys
import os
from PyQt4 import QtGui,QtCore
from threading import Thread
import subprocess
#from winpexpect import winspawn



class EmittingStream(QtCore.QObject):
    textWritten = QtCore.pyqtSignal(str)

    def write(self, text):
        self.textWritten.emit(str(text))

class gui(QtGui.QMainWindow):

    def __init__(self):
    # ...
        super(gui, self).__init__()
    # Install the custom output stream
        sys.stdout = EmittingStream(textWritten=self.normalOutputWritten)
        self.initUI()

    def normalOutputWritten(self, text):
        cursor = self.textEdit.textCursor()
        cursor.movePosition(QtGui.QTextCursor.End)
        cursor.insertText(text)
        self.textEdit.ensureCursorVisible()

    def callProgram(self):

        command="ping 127.0.0.1"
        #winspawn(command)
              py=subprocess.Popen(command.split(),stdout=subprocess.PIPE,stderr=subprocess.PIPE,shell=True)
        result,_=py.communicate()
        for line in result:
            print line
        print result


    def initUI(self):
        self.setGeometry(100,100,300,300)
        self.show()

        self.textEdit=QtGui.QTextEdit(self)
        self.textEdit.show()
        self.textEdit.setGeometry(20,40,200,200)

        print "changing sys.out"
        print "hello"

        thread = Thread(target = self.callProgram)
        thread.start()


#Function Main Start
def main():
    app = QtGui.QApplication(sys.argv)
    ui=gui()
    sys.exit(app.exec_())
#Function Main END

if __name__ == '__main__':
    main()

推荐答案

QProcess 与 subprocess 非常相似，但在 (Py)Qt 代码中使用更方便.因为它利用信号/插槽.此外，它以异步方式运行进程，因此您无需使用 QThread.

QProcess is very similar to subprocess, but it's much more convenient to use in (Py)Qt code. Because it utilizes signals/slots. Also, it runs the process asynchronously so you don't have use QThread.

我已经修改(并清理)了您的 QProcess 代码:

I've modified (and cleaned) your code for QProcess:

import sys
from PyQt4 import QtGui,QtCore

class gui(QtGui.QMainWindow):
    def __init__(self):
        super(gui, self).__init__()
        self.initUI()

    def dataReady(self):
        cursor = self.output.textCursor()
        cursor.movePosition(cursor.End)
        cursor.insertText(str(self.process.readAll()))
        self.output.ensureCursorVisible()

    def callProgram(self):
        # run the process
        # `start` takes the exec and a list of arguments
        self.process.start('ping',['127.0.0.1'])

    def initUI(self):
        # Layout are better for placing widgets
        layout = QtGui.QHBoxLayout()
        self.runButton = QtGui.QPushButton('Run')
        self.runButton.clicked.connect(self.callProgram)

        self.output = QtGui.QTextEdit()

        layout.addWidget(self.output)
        layout.addWidget(self.runButton)

        centralWidget = QtGui.QWidget()
        centralWidget.setLayout(layout)
        self.setCentralWidget(centralWidget)

        # QProcess object for external app
        self.process = QtCore.QProcess(self)
        # QProcess emits `readyRead` when there is data to be read
        self.process.readyRead.connect(self.dataReady)

        # Just to prevent accidentally running multiple times
        # Disable the button when process starts, and enable it when it finishes
        self.process.started.connect(lambda: self.runButton.setEnabled(False))
        self.process.finished.connect(lambda: self.runButton.setEnabled(True))


#Function Main Start
def main():
    app = QtGui.QApplication(sys.argv)
    ui=gui()
    ui.show()
    sys.exit(app.exec_())
#Function Main END

if __name__ == '__main__':
    main() 

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