使用看门狗和Tkinter

所以我有一个小脚本监视文件的更改/修改,如果文件被更改它会做一堆东西,如:

class Event(LoggingEventHandler):
def dispatch(self, event):
    #Do something here

if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO,
                        format='%(asctime)s - %(message)s',
                        datefmt='%Y-%m-%d %H:%M:%S')
    event_handler = Event()
    observer = Observer()
    observer.schedule(event_handler, my_path, recursive=True)
    observer.start()
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()

而且效果很好.但我有另一个脚本与一堆Tkinter小部件(典型的tk应用程序mainloop()).现在,当用户按下某个按钮时,我想调用看门狗监视文件更改,就像之前一样,调用dispatch()它会对它做一堆事情,并在同一个脚本中更新一些tkinter ui小部件,比如progressbars.

这个GUI的东西很新,无法弄清楚如何使看门狗循环和root.mainloop一起工作.怎么做到呢？

Watchdog在自己的线程中运行,因此您不需要做太多事情.如果要根据事件修改GUI,则应设置线程安全队列.Tkinter小部件不应该由多个线程修改,因此常见的模式是使用线程安全队列在线程之间进行通信.

以下示例将一个监视程序事件放在队列上,并event_generate在检测到监视程序事件时用于从观察者向GUI发送信号.我绝对不确定以下内容在所有情况下都能正常工作,因为我现在只能访问一个linux盒来测试它.但是,它似乎在Linux上运行正常.

import Tkinter as tk
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

from Queue import Queue
import sys

class CustomHandler(FileSystemEventHandler):
    def __init__(self, app):
        FileSystemEventHandler.__init__(self)
        self.app = app
    def on_created(self, event): app.notify(event)
    def on_deleted(self, event): app.notify(event)
    def on_modified(self, event): app.notify(event)
    def on_moved(self, event): app.notify(event)

class App(object):
    def __init__(self):
        path = sys.argv[1] if len(sys.argv) > 1 else "/tmp"
        handler = CustomHandler(self)
        self.observer = Observer()
        self.observer.schedule(handler, path, recursive=True)

        self.queue = Queue()
        self.root = tk.Tk()

        self.text = tk.Text(self.root)
        self.text.pack(fill="both", expand=True)

        self.text.insert("end", "Watching %s...\n" % path)

        self.root.bind("", self.shutdown)
        self.root.bind("<>", self.handle_watchdog_event)

        self.observer.start()

    def handle_watchdog_event(self, event):
        """Called when watchdog posts an event"""
        watchdog_event = self.queue.get()
        print("event type:", type(watchdog_event))
        self.text.insert("end", str(watchdog_event) + "\n")

    def shutdown(self, event):
        """Perform safe shutdown when GUI has been destroyed"""
        self.observer.stop()
        self.observer.join()

    def mainloop(self):
        """Start the GUI loop"""
        self.root.mainloop()

    def notify(self, event):
        """Forward events from watchdog to GUI"""
        self.queue.put(event)
        self.root.event_generate("<>", when="tail")

app = App()
app.mainloop()