python – 从次要线程将stdout和stderr重定向到PyQt4 QTextEdit

首先,1为了实现线程不安全,许多堆栈溢出的例子是！

解决方案是使用线程安全对象(如Python Queue.Queue)来调解信息的传输.我附下了一些示例代码,将stdout重定向到Python Queue.该队列由QThread读取,QThread通过Qt的信号/时隙机制将内容发送到主线程(发出信号是线程安全的).然后,主线程将文本写入文本编辑.

希望这是明确的,如果不是,请随时问问题！

编辑：请注意,提供的代码示例不会很好地清理QThreads,所以当您退出时会收到警告.我会把它留给你扩展到你的用例并清理线程

import sys
from Queue import Queue
from PyQt4.QtCore import *
from PyQt4.QtGui import *

# The new Stream Object which replaces the default stream associated with sys.stdout
# This object just puts data in a queue!
class WriteStream(object):
    def __init__(self,queue):
        self.queue = queue

    def write(self, text):
        self.queue.put(text)

# A QObject (to be run in a QThread) which sits waiting for data to come through a Queue.Queue().
# It blocks until data is available, and one it has got something from the queue, it sends
# it to the "MainThread" by emitting a Qt Signal 
class MyReceiver(QObject):
    mysignal = pyqtSignal(str)

    def __init__(self,queue,*args,**kwargs):
        QObject.__init__(self,*args,**kwargs)
        self.queue = queue

    @pyqtSlot()
    def run(self):
        while True:
            text = self.queue.get()
            self.mysignal.emit(text)

# An example QObject (to be run in a QThread) which outputs information with print
class LongRunningThing(QObject):
    @pyqtSlot()
    def run(self):
        for i in range(1000):
            print i

# An Example application QWidget containing the textedit to redirect stdout to
class MyApp(QWidget):
    def __init__(self,*args,**kwargs):
        QWidget.__init__(self,*args,**kwargs)

        self.layout = QVBoxLayout(self)
        self.textedit = QTextEdit()
        self.button = QPushButton('start long running thread')
        self.button.clicked.connect(self.start_thread)
        self.layout.addWidget(self.textedit)
        self.layout.addWidget(self.button)

    @pyqtSlot(str)
    def append_text(self,text):
        self.textedit.moveCursor(QTextCursor.End)
        self.textedit.insertPlainText( text )

    @pyqtSlot()
    def start_thread(self):
        self.thread = QThread()
        self.long_running_thing = LongRunningThing()
        self.long_running_thing.moveToThread(self.thread)
        self.thread.started.connect(self.long_running_thing.run)
        self.thread.start()

# Create Queue and redirect sys.stdout to this queue
queue = Queue()
sys.stdout = WriteStream(queue)

# Create QApplication and QWidget
qapp = QApplication(sys.argv)  
app = MyApp()
app.show()

# Create thread that will listen on the other end of the queue, and send the text to the textedit in our application
thread = QThread()
my_receiver = MyReceiver(queue)
my_receiver.mysignal.connect(app.append_text)
my_receiver.moveToThread(thread)
thread.started.connect(my_receiver.run)
thread.start()

qapp.exec_()