关于pyqt：watchdog(Python的库) – 如何在修改文件时发送信号？

watchdog (Python's library) - How to send signal when a file is modified?

我的用于检测何时修改了特定文件的类的代码：

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class MyEventHandler(FileSystemEventHandler, QtCore.QThread):
def __init__(self, filename):
super(MyEventHandler, self).__init__()
self.filename = filename

def on_modified(self, event):
if not event.is_directory and event.src_path.endswith(self.filename):
print"modified"
self.emit(QtCore.SIGNAL("fileModified"))

class WatchOutForFileModifications(QtCore.QThread):
def __init__(self, path, filename):
super(WatchOutForFileModifications, self).__init__()
self.path = path
self.filename = filename
self.observer = Observer()
self.event_handler = MyEventHandler(self.filename)
self.observer.schedule(self.event_handler, self.path, recursive=False)
self.observer.start()

def run(self):
while 1:
self.connect(self.event_handler, QtCore.SIGNAL("fileModified"), self.modified)

def modified(self):
self.emit(QtCore.SIGNAL("fileModified1"))

以及应用程序本身的代码段：

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class MainWindow(QtGui.QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
uic.loadUi('test.ui', self)

path ="somePath"
filename ="someName"

self.fileWatcher = WatchOutForFileModifications(path, filename)
self.fileWatcher.start()
self.connect(self.fileWatcher, QtCore.SIGNAL("fileModified1"), self.fileModified)
self.show()

def fileModified(self):
print 1

问题是，当文件被修改时，我得到一个不停的1正在打印的流。我意识到在WatchOutForFileModifications类中不应以这种方式发出/连接信号，但是我不明白API的方式：http://pythonhosted.org/watchdog/api.html#watchdog.observers .api.EventEmitter - 应该工作。至少我认为这是我应该用来监听文件修改的API。

编辑

一些修改后的工作代码：

导入系统
来自PyQt4导入QtGui，QtCore，uic

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from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer

class MyEventHandler(FileSystemEventHandler, QtCore.QThread):
def __init__(self, filename):
super(MyEventHandler, self).__init__()
self.filename = filename
self.signalName = str(filename) +"_modified"

def on_modified(self, event):
if not event.is_directory and event.src_path.endswith(self.filename):
self.emit(QtCore.SIGNAL(self.signalName))

class FileModificationWatcher(QtCore.QThread):
def __init__(self, path, filename):
super(FileModificationWatcher, self).__init__()
self.path = path
self.filename = filename
self.observer = Observer()
self.event_handler = MyEventHandler(self.filename)
self.observer.schedule(self.event_handler, self.path, recursive=False)
self.observer.start()

def run(self):
pass

def getEmitter(self):
return self.event_handler

def getSignalName(self):
return self.event_handler.signalName

class MainWindow(QtGui.QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
uic.loadUi('test.ui', self)

path ="somePath"
filename ="someName"

self.fileWatcher = FileModificationWatcher(path, filename)
self.fileWatcher.start()
self.connect(self.fileWatcher.getEmitter(), QtCore.SIGNAL(self.fileWatcher.getSignalName()), self.fileModified)
self.show()

def fileModified(self):
print 1

if __name__ =="__main__":
app = QtGui.QApplication(sys.argv)

window = MainWindow()
sys.exit(app.exec_())

问题是在WatchOutForFileModifications中，您反复将信号连接到运行功能中的插槽。要解决您遇到的问题，请调用self.connect并将其移至类的__init__中，如下所示：

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from PyQt4 import QtCore, QtGui
from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer

class MyEventHandler(FileSystemEventHandler, QtCore.QThread):
def __init__(self, filename):
super(MyEventHandler, self).__init__()
self.filename = filename

def on_modified(self, event):
if not event.is_directory and event.src_path.endswith(self.filename):
print("modified")
self.emit(QtCore.SIGNAL("fileModified"))

class WatchOutForFileModifications(QtCore.QThread):
def __init__(self, path, filename):
super(WatchOutForFileModifications, self).__init__()
self.path = path
self.filename = filename
self.observer = Observer()
self.event_handler = MyEventHandler(self.filename)
self.observer.schedule(self.event_handler, self.path, recursive=False)
self.observer.start()
self.connect(self.event_handler, QtCore.SIGNAL("fileModified"), self.modified)

def run(self):
pass

def modified(self):
self.emit(QtCore.SIGNAL("fileModified1"))

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

path = r'D:\Code\'
filename ="Hexagon_Grid_Creation.py"

self.fileWatcher = WatchOutForFileModifications(path, filename)
#self.fileWatcher.start()
self.connect(self.fileWatcher, QtCore.SIGNAL("fileModified1"), self.fileModified)
self.show()

def fileModified(self):
print(1)

if __name__ == '__main__':
app = QtGui.QApplication([])
window = MainWindow()
window.show()
app.exec_()

在这种情况下，您可能不需要QThread。该文件正在由事件处理程序监视，因此您实际上不需要在后台运行其他任何内容。我认为您可以完全取消该类，而只需实例化MainWindow类中的事件处理程序即可。