Resetting a wxPython app / destroying everything and starting from initial frame - python-3.x

Question

I've read other answers here, but they all seem to deal with just closing an app altogether, making sure all processes and frames and such are destroyed in the process. What I want to do is a little different.
My app consists of three frames (StartFrame, ParaFrame, ResultFrame) as well as a custom class for storing and manipulating data. The basics are: StartFrame is just some text and a "start" button. "Start" creates an instance of ParaFrame, hides the StartFrame, and shows the ParaFrame instance. Paraframe has a bunch of widgets for the user to select a file and how to analyze it. When all the fields are entered, an "Analyze" button pops up, which (when clicked) instantiates the custom DataHandler class, sets its parameters according to the user selections, calls a DataHandler method which analyzes the data, hides itself, and instantiates+shows the ResultsFrame. Not surprisingly, the ResultsFrame shows the results of the analysis.
I want to add a "Start Over" control which will destroy everything (all the frames, panels, the DataHandler instance, etc.) and display a fresh StartFrame instance, or otherwise destroy everything except the already-instantiated-but-hidden StartFrame, showing that frame again, but I'm at a loss.
A simplified example follows:
import wx
class StartFrame(wx.Frame):
"""App start frame"""
FRAME_MIN_SIZE = (900,600)
def __init__(self, parent):
wx.Frame.__init__(self, parent=parent,
id=wx.ID_ANY, title="LOD Calculator", size=wx.Size(900,600),
style=wx.CAPTION|wx.CLOSE_BOX|wx.MINIMIZE_BOX|wx.SYSTEM_MENU|wx.RESIZE_BORDER|wx.TAB_TRAVERSAL)
self.startpnl = wx.Panel(self)
self.startvsizer=wx.BoxSizer(wx.VERTICAL)
self.startbtnsizer=wx.BoxSizer(wx.HORIZONTAL)
self.btn = wx.Button(self.startpnl, wx.ID_ANY, "Start Analysis",\
size = (200,60))
self.btn.Bind(wx.EVT_BUTTON, self._OnStart)
self.startbtnsizer.AddStretchSpacer()
self.startbtnsizer.Add(self.btn, 0, wx.CENTER)
self.startbtnsizer.AddStretchSpacer()
self.startvsizer.AddStretchSpacer()
self.startvsizer.Add(self.startbtnsizer, wx.SizerFlags().Expand().Border(wx.ALL, 25))
self.startvsizer.AddStretchSpacer()
self.startpnl.SetSizerAndFit(self.startvsizer)
def _OnStart(self,event):
self.frm2 = ParaFrame(None)
self.Hide()
self.frm2.Show()
class ParaFrame(wx.Frame):
"""Data load frame"""
FRAME_MIN_SIZE = (950,800)
def __init__(self, parent):
wx.Frame.__init__(self, parent=parent,
id=wx.ID_ANY, title="LOD Calculator", size=wx.Size(950,800),
style=wx.CAPTION|wx.CLOSE_BOX|wx.MINIMIZE_BOX|wx.SYSTEM_MENU|wx.RESIZE_BORDER|wx.TAB_TRAVERSAL)
self.mainpnl = wx.Panel(self)
self.mainsizer = wx.BoxSizer(wx.HORIZONTAL)
self.vsizer = wx.BoxSizer(wx.VERTICAL)
self.analyzebtn = wx.Button(self.mainpnl, wx.ID_ANY, u"Analyze",\
wx.DefaultPosition, wx.DefaultSize, 0)
self.vsizer.AddStretchSpacer()
self.vsizer.Add(self.analyzebtn, 0, wx.ALL, 10)
self.vsizer.AddStretchSpacer()
self.mainsizer.AddStretchSpacer()
self.mainsizer.Add(self.vsizer, wx.SizerFlags().Expand().Border(wx.ALL, 25))
self.mainsizer.AddStretchSpacer()
self.mainpnl.SetSizerAndFit(self.mainsizer)
self.analyzebtn.Bind(wx.EVT_BUTTON, self._analyze)
def _analyze(self, event):
dhandler = DataHandler(self)
dhandler.data = "a bunch"
dhandler.data2 = " of data"
dhandler.data3 = " goes here"
dhandler._analyzeData()
self.resfrm = ResultFrame(self, dhandler.data, dhandler.data2)
self.Hide()
self.resfrm.Show()
class DataHandler:
def __init__(self,parent):
self.data = ''
self.data2 = ''
self.data3 = ''
def _analyzeData(self):
anastr = self.data + self.data2 + " gets analyzed"
print(anastr)
class ResultFrame(wx.Frame):
def __init__(self, parent, targets, dftables):
super(ResultFrame, self).__init__(parent, title="results", size=(1535,935))
self.targets = targets
self.dftables = dftables
self.InitUI()
self.Layout()
def InitUI(self):
self.mainpnl = wx.Panel(self)
self.mainsizer = wx.BoxSizer(wx.HORIZONTAL)
self.vsizer = wx.BoxSizer(wx.VERTICAL)
self.restartbtn = wx.Button(self.mainpnl, wx.ID_ANY, u"Start Over",\
wx.DefaultPosition, wx.DefaultSize, 0)
self.vsizer.AddStretchSpacer()
self.vsizer.Add(self.restartbtn, 0, wx.ALL, 10)
self.vsizer.AddStretchSpacer()
self.mainsizer.AddStretchSpacer()
self.mainsizer.Add(self.vsizer, wx.SizerFlags().Expand().Border(wx.ALL, 25))
self.mainsizer.AddStretchSpacer()
self.mainpnl.SetSizerAndFit(self.mainsizer)
self.restartbtn.Bind(wx.EVT_BUTTON, self.OnRestart)
### this is where I try to destroy the ParaFrame instance and everything spawned by it, unsuccessfully
def OnRestart(self, event):
frm.frm2.Destroy()
frm.Show()
def main():
import wx.lib.mixins.inspection
app = wx.App()
frm = StartFrame(None)
frm.Show()
wx.lib.inspection.InspectionTool().Show(refreshTree=True)
app.MainLoop()
if __name__ == "__main__":
main()
As you can see, in the ResultFrame I have a "Start Over" button bound to a method in which I try to destroy the ParaFrame instance (and thus the DataHandler and ResultFrame instances spawned from it) by using frm.frm2.Destroy(), but get an error:
Traceback (most recent call last):
File "C:\Python\Scripts\stackexchange code.py", line 102, in OnRestart
frm.frm2.Destroy()
NameError: name 'frm' is not defined
If I change the line to just frm2.Destroy(), I get the same error, but stating name 'frm2' is not defined.
What am I doing wrong here, and how can I accomplish my goal? I'm still newish to OOP and quite new to wxPython, so any help is appreciate it. All I want is for that button to destroy everything and display the/an initial StartFrame again. Thank you :)

Answer 1

As long as you create each class without a parent, you can use self.Destroy() after creating the next frame in the chain, without it destroying any children. (Pass any data required as a parameter other than parent)
So your code, looks something like this:
import wx
class StartFrame(wx.Frame):
"""App start frame"""
FRAME_MIN_SIZE = (900,600)
def __init__(self, parent):
wx.Frame.__init__(self, parent=parent,
id=wx.ID_ANY, title="Load Calculator", size=wx.Size(900,600))
self.startpnl = wx.Panel(self)
self.startvsizer=wx.BoxSizer(wx.VERTICAL)
self.startbtnsizer=wx.BoxSizer(wx.HORIZONTAL)
self.btn = wx.Button(self.startpnl, wx.ID_ANY, "Start Analysis",\
size = (200,60))
self.btn.Bind(wx.EVT_BUTTON, self._OnStart)
self.startbtnsizer.AddStretchSpacer()
self.startbtnsizer.Add(self.btn, 0, wx.CENTER)
self.startbtnsizer.AddStretchSpacer()
self.startvsizer.AddStretchSpacer()
self.startvsizer.Add(self.startbtnsizer, wx.SizerFlags().Expand().Border(wx.ALL, 25))
self.startvsizer.AddStretchSpacer()
self.startpnl.SetSizerAndFit(self.startvsizer)
def _OnStart(self,event):
frm2 = ParaFrame(None)
frm2.Show()
self.Destroy()
class ParaFrame(wx.Frame):
"""Data load frame"""
FRAME_MIN_SIZE = (950,800)
def __init__(self, parent):
wx.Frame.__init__(self, parent=parent,
id=wx.ID_ANY, title="Load Calculator", size=wx.Size(900,600))
self.mainpnl = wx.Panel(self)
self.mainsizer = wx.BoxSizer(wx.HORIZONTAL)
self.vsizer = wx.BoxSizer(wx.VERTICAL)
self.analyzebtn = wx.Button(self.mainpnl, wx.ID_ANY, u"Analyze",\
wx.DefaultPosition, wx.DefaultSize, 0)
self.vsizer.AddStretchSpacer()
self.vsizer.Add(self.analyzebtn, 0, wx.ALL, 10)
self.vsizer.AddStretchSpacer()
self.mainsizer.AddStretchSpacer()
self.mainsizer.Add(self.vsizer, wx.SizerFlags().Expand().Border(wx.ALL, 25))
self.mainsizer.AddStretchSpacer()
self.mainpnl.SetSizerAndFit(self.mainsizer)
self.analyzebtn.Bind(wx.EVT_BUTTON, self._analyze)
def _analyze(self, event):
dhandler = DataHandler(self)
dhandler.data = "a bunch"
dhandler.data2 = " of data"
dhandler.data3 = " goes here"
dhandler._analyzeData()
resfrm = ResultFrame(None, dhandler.data, dhandler.data2)
resfrm.Show()
self.Destroy()
class DataHandler:
def __init__(self,parent):
self.data = ''
self.data2 = ''
self.data3 = ''
def _analyzeData(self):
anastr = self.data + self.data2 + " gets analyzed"
print(anastr)
class ResultFrame(wx.Frame):
def __init__(self, parent, targets, dftables):
super(ResultFrame, self).__init__(parent, title="Results", size=(900,600))
self.targets = targets
self.dftables = dftables
self.InitUI()
self.Layout()
def InitUI(self):
self.mainpnl = wx.Panel(self)
self.mainsizer = wx.BoxSizer(wx.HORIZONTAL)
self.vsizer = wx.BoxSizer(wx.VERTICAL)
self.restartbtn = wx.Button(self.mainpnl, wx.ID_ANY, u"Start Over",\
wx.DefaultPosition, wx.DefaultSize, 0)
self.vsizer.AddStretchSpacer()
self.vsizer.Add(self.restartbtn, 0, wx.ALL, 10)
self.vsizer.AddStretchSpacer()
self.mainsizer.AddStretchSpacer()
self.mainsizer.Add(self.vsizer, wx.SizerFlags().Expand().Border(wx.ALL, 25))
self.mainsizer.AddStretchSpacer()
self.mainpnl.SetSizerAndFit(self.mainsizer)
self.restartbtn.Bind(wx.EVT_BUTTON, self.OnRestart)
### this is where I try to destroy the ParaFrame instance and everything spawned by it, unsuccessfully
def OnRestart(self, event):
frm = StartFrame(None)
frm.Show()
self.Destroy()
def main():
app = wx.App()
frm = StartFrame(None)
frm.Show()
app.MainLoop()
if __name__ == "__main__":
main()