wxPython WebView:错误时如何重新加载?

时间:2019-04-16 09:35:51

标签: python python-3.x webview event-handling wxpython

我正在使用wx.html2.WebView在对话框中加载网站,可以正常运行

问题:如果由于任何原因无法访问网站,则输出为Could not connect: Connection refused

期望的行为:在每次失败的x秒后,尝试重新加载URL

import wx 
import wx.html2 
import time

URL = "http://mydomain.tld"

class MyBrowser(wx.Frame): 
  def __init__(self, *args, **kwds): 
    wx.Frame.__init__(self, *args, **kwds) 
    self.browser = wx.html2.WebView.New(self) 
    self.browser.Bind(wx.html2.EVT_WEBVIEW_ERROR, self.on_webview_error)

  def on_webview_error(self, evt):
    # Printing works
    print("Error: can't load page, try again in 3 seconds.")
    # Sleeping works
    time.sleep(3)
    # Reloading doesn't work
    self.browser.LoadURL(URL) # OR self.browser.Reload()
    # Weird: Error is rendered now


if __name__ == '__main__': 
  app = wx.App() 
  dialog = MyBrowser(None, -1) 
  dialog.browser.LoadURL(URL) 
  dialog.Show() 
  app.MainLoop() 

该问题发生在on_webview_error(self, evt)中。我的猜测是我没有正确使用该功能,特别是因为错误消息是在重新加载后呈现的。

有什么主意吗?
预先感谢!

2 个答案:

答案 0 :(得分:1)

那里发生了一些奇怪的事情!
我强迫它起作用的唯一方法是每次都重新定义WebView。我也可能每次都对Destroy充满热情。
这可行,但不一定完全符合您的要求。

import wx
import wx.html2
import time

URL = "http://mydomain.tld"

class MyBrowser(wx.Frame):
    def __init__(self, *args, **kwds):
        wx.Frame.__init__(self, *args, **kwds)
        self.url = URL
        self.browser = wx.html2.WebView.New(self, -1, size=(900,600))
        self.browser.Bind(wx.html2.EVT_WEBVIEW_ERROR, self.on_webview_error)
        self.browser.Bind(wx.html2.EVT_WEBVIEW_LOADED, self.on_webview_load)
        self.retries = 0
        self.max_retries = 10

    def on_webview_error(self, evt):
        self.URL = evt.GetURL()
        print(self.URL)
        self.retries += 1
        if self.retries > self.max_retries: # Give up
            self.Destroy()
        print("Error {} of {} attempts to load {}, trying again in 3 seconds.".format(self.retries,self.max_retries,self.URL))
        if self.retries > 5: # Try alternate
            self.URL = "http://wxPython.org"
            print("Swapping to alternate Url "+self.URL)
        self.browser.Destroy()

        time.sleep(3)

        self.browser = wx.html2.WebView.New(self, -1, size=(900,600))
        self.browser.Bind(wx.html2.EVT_WEBVIEW_ERROR, self.on_webview_error)
        self.browser.Bind(wx.html2.EVT_WEBVIEW_LOADED, self.on_webview_load)
        self.browser.LoadURL(self.URL)

    def on_webview_load(self, evt):
        print(self.URL, "Load complete")

if __name__ == '__main__':
  app = wx.App()
  dialog = MyBrowser(None, -1)
  dialog.browser.LoadURL(URL)
  dialog.Show()
  app.MainLoop()

答案 1 :(得分:1)

在wxPython中,您总是有一个主线程,该线程负责绘制和更新GUI。在您的MWE中,行time.sleep(3)允许您等待3秒,然后再次尝试重新加载页面。但是,这样做的副作用是,在能够更新GUI并显示错误消息之前,将程序的主线程发送到睡眠状态。如果将time.sleep(3)行移到另一个线程,则可以毫无问题地更新GUI。这是一个解决方案:

import wx 
import wx.html2 
import time
import _thread
from pubsub import pub

URL = "https://mydomain.tld"

class MyBrowser(wx.Frame): 
    def __init__(self, *args, **kwds): 
        wx.Frame.__init__(self, *args, **kwds) 
        self.browser = wx.html2.WebView.New(self) 
        self.browser.Bind(wx.html2.EVT_WEBVIEW_ERROR, self.on_webview_error)
        self.counter = 0
        pub.subscribe(self.loadwww, 'Try Again')
        pub.subscribe(self.loadalt, 'Give UP')

    def loadwww(self):
        self.browser.LoadURL("https://mydomain.tld")

    def loadalt(self):
        self.browser.LoadURL("https://www.google.com")

    def on_webview_error(self, evt):
        self.counter += 1
        _thread.start_new_thread(self.wait, (3,))   

    def wait(self, sec):
        if self.counter <= 5:
            print(self.counter)
            print("Error: can't load page, try again in 3 seconds.")
            time.sleep(sec)
            wx.CallAfter(pub.sendMessage, 'Try Again')
        else:
            wx.CallAfter(pub.sendMessage, 'Give UP')    

if __name__ == '__main__': 
    app = wx.App() 
    dialog = MyBrowser(None, -1) 
    dialog.browser.LoadURL(URL) 
    dialog.Show() 
    app.MainLoop()