Question

我有一个跟踪运行上传进度的FTP功能，但我对线程的理解有限，我无法实现一个有效的解决方案...我想在我当前的应用程序中添加一个GUI进度条使用线程。有人可以使用可以从另一个正在运行的线程更新的异步线程向我展示一个基本功能吗？

def ftpUploader():
    BLOCKSIZE = 57344 # size 56 kB

    ftp = ftplib.FTP()
    ftp.connect(host)
    ftp.login(login, passwd)
    ftp.voidcmd("TYPE I")
    f = open(zipname, 'rb')
    datasock, esize = ftp.ntransfercmd(
        'STOR %s' % os.path.basename(zipname))
    size = os.stat(zipname)[6]
    bytes_so_far = 0
    print 'started'
    while 1:
        buf = f.read(BLOCKSIZE)
        if not buf:
            break
        datasock.sendall(buf)
        bytes_so_far += len(buf)
        print "\rSent %d of %d bytes %.1f%%\r" % (
              bytes_so_far, size, 100 * bytes_so_far / size)
        sys.stdout.flush()

    datasock.close()
    f.close()
    ftp.voidresp()
    ftp.quit()
    print 'Complete...'

Answer 1

以下是线程的快速概述，以防万一:)我不会详细介绍GUI内容，除了说你应该查看wxWidgets。每当你做一些需要很长时间的事情时，比如：

from time import sleep
for i in range(5):
    sleep(10)

您会注意到，对于用户来说，整个代码块似乎需要50秒。在这5秒钟内，您的应用程序无法执行更新界面等任何操作，因此看起来它已被冻结。为了解决这个问题，我们使用线程。

通常这个问题有两个部分;你要处理的整体事情，以及需要一段时间的操作，我们想要切断。在这种情况下，整个集合是for循环，我们想要切断的操作是sleep（10）函数。

这是基于我们之前的示例的线程代码的快速模板。您应该能够将代码用于此示例。

from threading import Thread
from time import sleep

# Threading.
# The amount of seconds to wait before checking for an unpause condition.
# Sleeping is necessary because if we don't, we'll block the os and make the
# program look like it's frozen.
PAUSE_SLEEP = 5

# The number of iterations we want.
TOTAL_ITERATIONS = 5

class myThread(Thread):
    '''
    A thread used to do some stuff.
    '''
    def __init__(self, gui, otherStuff):
        '''
        Constructor. We pass in a reference to the GUI object we want
        to update here, as well as any other variables we want this
        thread to be aware of.
        '''
        # Construct the parent instance.
        Thread.__init__(self)

        # Store the gui, so that we can update it later.
        self.gui = gui

        # Store any other variables we want this thread to have access to.
        self.myStuff = otherStuff

        # Tracks the paused and stopped states of the thread.
        self.isPaused = False
        self.isStopped = False

    def pause(self):
        '''
        Called to pause the thread.
        '''
        self.isPaused = True

    def unpause(self):
        '''
        Called to unpause the thread.
        '''
        self.isPaused = False

    def stop(self):
        '''
        Called to stop the thread.
        '''
        self.isStopped = True

    def run(self):
        '''
        The main thread code.
        '''
        # The current iteration.
        currentIteration = 0

        # Keep going if the job is active.
        while self.isStopped == False:
            try:
                # Check for a pause.
                if self.isPaused:
                    # Sleep to let the os schedule other tasks.
                    sleep(PAUSE_SLEEP)
                    # Continue with the loop.
                    continue

                # Check to see if we're still processing the set of
                # things we want to do.
                if currentIteration < TOTAL_ITERATIONS:
                    # Do the individual thing we want to do.
                    sleep(10)
                    # Update the count.
                    currentIteration += 1
                    # Update the gui.
                    self.gui.update(currentIteration,TOTAL_ITERATIONS)
                else:
                    # Stop the loop.
                    self.isStopped = True

            except Exception as exception:
                # If anything bad happens, report the error. It won't
                # get written to stderr.
                print exception
                # Stop the loop.
                self.isStopped = True

        # Tell the gui we're done.
        self.gui.stop()

要调用此主题，您所要做的就是：

aThread = myThread(myGui,myOtherStuff)
aThread.start()

帮助为GUI进度添加线程

1 个答案: