使用 MVC 设计模式时如何加载重模型

Question

我正在使用 wxPython 和我使用 Tensorflow 创建的深度学习模型构建一个应用程序。我使用的设计模式是 MVC。 我的问题是深度学习模型非常重，加载需要很长时间（大约 2 分钟），同时 GUI 挂起。 我创建了一个描述该过程的示例代码。 这是加载时 GUI 的样子：

enter image description here

这是加载后 GUI 的样子： enter image description here

问题是如何让应用程序在模型加载时运行？ 我还想在 GUI 中添加一条状态行，指示模型正在加载或已经加载。

我正在添加显示我的应用程序是如何构建的示例代码。

import wx
import time

class Model:
    def __init__(self):
        '''This part is simulating the loading of tensorflow'''
        x = 0
        while x < 15:
            time.sleep(1)
            print(x)
            x += 1

class View(wx.Frame):
    def __init__(self, parent, title):
        super(View, self).__init__(parent, title=title, size=(400, 400))
        self.InitUI()

    def InitUI(self):
        # Defines the GUI controls
        masterPanel = wx.Panel(self)
        masterPanel.SetBackgroundColour("gold")
        self.vbox = wx.BoxSizer(wx.VERTICAL)
        self.fgs = wx.FlexGridSizer(6, 2, 10, 25)
        id = wx.StaticText(self, label="ID:")
        firstName = wx.StaticText(self, label="First name:")
        lastName = wx.StaticText(self, label="Last name:")
        self.idTc = wx.TextCtrl(self)
        self.firstNameTc = wx.TextCtrl(self)
        self.lastNameTc = wx.TextCtrl(self)
        self.fgs.AddMany([id, (self.idTc, 1, wx.EXPAND),
                         firstName, (self.firstNameTc, 1, wx.EXPAND),
                         lastName, (self.lastNameTc, 1, wx.EXPAND)])
        self.vbox.Add(self.fgs, proportion=1, flag=wx.ALL | wx.EXPAND,
   border=15)
        self.SetSizer(self.vbox)
        self.vbox.Fit(self)
        self.Layout()

class Controller:
    def __init__(self):
        self.view = View(None, title='Test')
        self.view.Show()
        self.model = Model()

def main():
    app = wx.App()
    controller = Controller()
    app.MainLoop()

if __name__ == '__main__':
    main()

Answer 1

您可以使用_thread 模块和PyPubSub 模块在模型加载期间保持主线程完全正常工作。

但是，请记住，如果您在 GUI 中有 wx.Button 绑定到 method A 并且 method A 需要加载完整模型才能正常运行，那么用户将能够单击 wx.Button并且程序可能会挂起，因为模型仍未完全加载。如果是这种情况，您可以使用方法Disable()（加载模型时）和Enable()（加载模型后）来防止这种情况。

带有 cmets 的代码 (####)。

import wx
import time
import _thread
from pubsub import pub

class Model:
    def __init__(self):
        '''This part is simulating the loading of tensorflow'''
        x = 0
        while x < 15:
            time.sleep(1)
            print(x)
            #### This is how you broadcast the 'Loading' message 
            #### from a different thread.
            wx.CallAfter(pub.sendMessage, 'Loading', x=x)
            x += 1
        #### The same as before
        wx.CallAfter(pub.sendMessage, 'Loading', x=x)

class View(wx.Frame):
    def __init__(self, parent, title):
        super(View, self).__init__(parent, title=title, size=(400, 400))
        self.InitUI()

    def InitUI(self):
        # Defines the GUI controls
        #### It needed to set the size of the panel to cover the frame
        #### because it was not covering the entire frame before
        masterPanel = wx.Panel(self, size=(400, 400))
        masterPanel.SetBackgroundColour("gold")
        self.vbox = wx.BoxSizer(wx.VERTICAL)
        self.fgs = wx.FlexGridSizer(6, 2, 10, 25)
        id = wx.StaticText(self, label="ID:")
        firstName = wx.StaticText(self, label="First name:")
        lastName = wx.StaticText(self, label="Last name:")
        self.idTc = wx.TextCtrl(self)
        self.firstNameTc = wx.TextCtrl(self)
        self.lastNameTc = wx.TextCtrl(self)
        self.fgs.AddMany([id, (self.idTc, 1, wx.EXPAND),
                         firstName, (self.firstNameTc, 1, wx.EXPAND),
                         lastName, (self.lastNameTc, 1, wx.EXPAND)])
        self.vbox.Add(self.fgs, proportion=1, flag=wx.ALL | wx.EXPAND,
   border=15)
        self.SetSizer(self.vbox)
        self.vbox.Fit(self)
        self.Layout()

        #### Create status bar to show loading progress. 
        self.statusbar = self.CreateStatusBar(1)
        self.statusbar.SetStatusText('Loading model')
        #### Set the size of the window because the status bar steals space
        #### in the height direction.
        self.SetSize(wx.DefaultCoord, 160)
        #### Subscribe the class to the message 'Loading'. This means that every
        #### time the meassage 'Loading' is broadcast the method 
        #### ShowLoadProgress will be executed.
        pub.subscribe(self.ShowLoadProgress, 'Loading')
        #### Start the thread that will load the model
        _thread.start_new_thread(self.LoadModel, ('test',))

    def LoadModel(self, test):
        """
        Load the Model
        """
        #### Change depending on how exactly are you going to create/load the 
        #### model
        self.model = Model()

    def ShowLoadProgress(self, x):
        """
        Show the loading progress 
        """
        if x < 15:
            self.statusbar.SetStatusText('Loading progress: ' + str(x))
        else:
            self.statusbar.SetStatusText('All loaded')

class Controller:
    def __init__(self):
        self.view = View(None, title='Test')
        self.view.Show()
        #### The line below is not needed now because the model is 
        #### loaded now from the thread started in View.InitUI
        #self.model = Model()

def main():
    app = wx.App()
    controller = Controller()
    app.MainLoop()

if __name__ == '__main__':
    main()

如果您从 class View 中的方法加载模型，那么您将不需要 PyPubSub 模块，因为您只需调用 wx.CallAfter(self.ShowLoadProgress, x)

Answer 2

只是为了好玩，因为我更喜欢 kbr85 给我的简单的第一个答案的答案，这是一个线程变体，在 statusbar 中带有一个 gauge 和一个忙碌光标，尽管我的屏幕截图程序没有选择它.
有一个 Stop 按钮，一旦加载完成，statusbar 就会被删除。
我没有使用pubsub，而是使用wxpython event 进行通信。

import wx
import time
from threading import Thread
import wx.lib.newevent
progress_event, EVT_PROGRESS_EVENT = wx.lib.newevent.NewEvent()
load_status=["Model Loading","Model Loaded","Model Cancelled"]

class Model(Thread):
    def __init__(self,parent):
        Thread.__init__(self)
        '''This thread simulates the loading of tensorflow'''
        self.stopthread = 0
        self.target = parent
        self.start()

    def run(self):
        while not self.stopthread:
            for i in range(20):
                if self.stopthread:
                    break
                time.sleep(0.5)
                evt = progress_event(count=i, status=self.stopthread)
                wx.PostEvent(self.target, evt)
            if self.stopthread == 0:
                self.stopthread = 1
        evt = progress_event(count=i, status=self.stopthread)
        wx.PostEvent(self.target, evt)

    def terminate(self):
        self.stopthread = 2

class View(wx.Frame):
    def __init__(self, parent, title):
        super(View, self).__init__(parent, title=title, size=(400, 400))
        self.InitUI()

    def InitUI(self):
        self.vbox = wx.BoxSizer(wx.VERTICAL)
        self.fgs = wx.FlexGridSizer(6, 2, 10, 25)
        id = wx.StaticText(self, label="ID:")
        firstName = wx.StaticText(self, label="First name:")
        lastName = wx.StaticText(self, label="Last name:")
        self.idTc = wx.TextCtrl(self)
        self.firstNameTc = wx.TextCtrl(self)
        self.lastNameTc = wx.TextCtrl(self)
        self.stop = wx.Button(self, -1, "Stop Load")

        self.fgs.AddMany([id, (self.idTc, 1, wx.EXPAND),
                         firstName, (self.firstNameTc, 1, wx.EXPAND),
                         lastName, (self.lastNameTc, 1, wx.EXPAND),
                         (self.stop,1,wx.EXPAND)])

        self.vbox.Add(self.fgs, proportion=1, flag=wx.ALL | wx.EXPAND,border=15)
        #Bind to the progress event issued by the thread
        self.Bind(EVT_PROGRESS_EVENT, self.OnProgress)
        #Bind to Stop button
        self.Bind(wx.EVT_BUTTON, self.OnStop)
        #Bind to Exit on frame close
        self.Bind(wx.EVT_CLOSE, self.OnExit)
        self.SetSizer(self.vbox)
        self.Layout()

        self.statusbar = self.CreateStatusBar(2)
        self.text = wx.StaticText(self.statusbar,-1,("No Model loaded"))
        self.progress = wx.Gauge(self.statusbar, range=20)
        sizer = wx.BoxSizer(wx.HORIZONTAL)
        sizer.Add(self.text, 0, wx.ALIGN_TOP|wx.ALL, 5)
        sizer.Add(self.progress, 1, wx.ALIGN_TOP|wx.ALL, 5)
        self.statusbar.SetSizer(sizer)
        wx.BeginBusyCursor()
        self.loadthread = Model(self)


    def OnProgress(self, event):
        self.text.SetLabel(load_status[event.status])
        #self.progress.SetValue(event.count)
        #or for indeterminate progress
        self.progress.Pulse()
        if event.status != 0:
            self.statusbar.Hide()
            wx.EndBusyCursor()
            self.Layout()

    def OnStop(self, event):
        if self.loadthread.isAlive():
            self.loadthread.terminate() # Shutdown the thread
            self.loadthread.join() # Wait for it to finish

    def OnExit(self, event):
        if self.loadthread.isAlive():
            self.loadthread.terminate() # Shutdown the thread
            self.loadthread.join() # Wait for it to finish
        self.Destroy()

class Controller:
    def __init__(self):
        self.view = View(None, title='Test')
        self.view.Show()

def main():
    app = wx.App()
    controller = Controller()
    app.MainLoop()

if __name__ == '__main__':
    main()

Answer 3

您应该在self.view.Show() 命令之后调用wx.GetApp().Yield()，这会将控制权暂时释放给MainLoop。
如果模型加载代码以增量方式执行，您也可以在加载期间定期调用 Yield。
下面是一个简单的方法来通知用户正在发生的事情。如果您想要取消模型加载的选项，则必须将其包装在一个对话框中，假设它是增量加载的。

import wx
import time

class Model:
    def __init__(self):
        '''This part is simulating the loading of tensorflow'''
        x = 0
        #If the model load is perform in increments you could call wx.Yield
        # between the increments.
        while x < 15:
            time.sleep(1)
            wx.GetApp().Yield()
            print(x)
            x += 1

class View(wx.Frame):
    def __init__(self, parent, title):
        super(View, self).__init__(parent, title=title, size=(400, 400))
        self.InitUI()

    def InitUI(self):
        # Defines the GUI controls
        #masterPanel = wx.Panel(self)
        #masterPanel.SetBackgroundColour("gold")
        self.vbox = wx.BoxSizer(wx.VERTICAL)
        self.fgs = wx.FlexGridSizer(6, 2, 10, 25)
        id = wx.StaticText(self, label="ID:")
        firstName = wx.StaticText(self, label="First name:")
        lastName = wx.StaticText(self, label="Last name:")
        self.idTc = wx.TextCtrl(self)
        self.firstNameTc = wx.TextCtrl(self)
        self.lastNameTc = wx.TextCtrl(self)
        self.fgs.AddMany([id, (self.idTc, 1, wx.EXPAND),
                         firstName, (self.firstNameTc, 1, wx.EXPAND),
                         lastName, (self.lastNameTc, 1, wx.EXPAND)])
        self.vbox.Add(self.fgs, proportion=1, flag=wx.ALL | wx.EXPAND,
   border=15)
        self.CreateStatusBar() # A Statusbar in the bottom of the window
        self.StatusBar.SetStatusText("No model loaded", 0)
        self.SetSizer(self.vbox)
        self.vbox.Fit(self)
        self.Layout()

class Controller:
    def __init__(self):
        self.view = View(None, title='Test')
        self.view.Show()
        self.view.SetStatusText("Model loading", 0)
        wait = wx.BusyInfo("Please wait, loading model...")
        #Optionally add parent to centre message on self.view
        #wait = wx.BusyInfo("Please wait, loading model...", parent=self.view)
        wx.GetApp().Yield()
        self.model = Model()
        self.view.SetStatusText("Model loaded", 0)
        del wait

def main():
    app = wx.App()
    controller = Controller()
    app.MainLoop()

if __name__ == '__main__':
    main()