wxgui: Make sure to only start the flow graph once all init is done

Currently we start the flow graph in the stdframe constructor.
However at that point, the frame isn't attached to the app and it's not
"shown" yet which means some UI operations can still fail.

This is a race condition which happens on OSX. You can reproduce it on
linux as well by adding a sleep(1) after starting the flow graph.

Signed-off-by: Sylvain Munaut <[email protected]>

Author: smunaut

gr-wxgui/python/wxgui/stdgui2.py

@@ -46,16 +46,20 @@ def __init__ (self, top_block_maker, title="GNU Radio", nstatus=2,
         wx.App.__init__ (self, redirect=False)
 
     def OnInit (self):
-        frame = stdframe (self.top_block_maker, self.title, self._nstatus,
-                          self._max_noutput_items)
+        frame = stdframe (self.top_block_maker, self.title, self._nstatus)
         frame.Show (True)
         self.SetTopWindow (frame)
+
+        if(self._max_noutput_items is not None):
+            frame.top_block().start (self._max_noutput_items)
+        else:
+            frame.top_block().start ()
+
         return True
 
 
 class stdframe (wx.Frame):
-    def __init__ (self, top_block_maker, title="GNU Radio", nstatus=2,
-                  max_nouts=None):
+    def __init__ (self, top_block_maker, title="GNU Radio", nstatus=2):
         # print "stdframe.__init__"
         wx.Frame.__init__(self, None, -1, title)
 
@@ -69,7 +73,7 @@ def __init__ (self, top_block_maker, title="GNU Radio", nstatus=2,
         self.SetMenuBar (mainmenu)
 
         self.Bind (wx.EVT_CLOSE, self.OnCloseWindow)
-        self.panel = stdpanel (self, self, top_block_maker, max_nouts)
+        self.panel = stdpanel (self, self, top_block_maker)
         vbox = wx.BoxSizer(wx.VERTICAL)
         vbox.Add(self.panel, 1, wx.EXPAND)
         self.SetSizer(vbox)
@@ -85,8 +89,7 @@ def top_block (self):
         return self.panel.top_block
 
 class stdpanel (wx.Panel):
-    def __init__ (self, parent, frame, top_block_maker,
-                  max_nouts=None):
+    def __init__ (self, parent, frame, top_block_maker):
         # print "stdpanel.__init__"
         wx.Panel.__init__ (self, parent, -1)
         self.frame = frame
@@ -97,11 +100,6 @@ def __init__ (self, parent, frame, top_block_maker,
         self.SetAutoLayout (True)
         vbox.Fit (self)
 
-        if(max_nouts is not None):
-            self.top_block.start (max_nouts)
-        else:
-            self.top_block.start ()
-
 class std_top_block (gr.top_block):
     def __init__ (self, parent, panel, vbox, argv):
         # Call the hier_block2 constructor