An simple interface plotted by matplotlib and cartopy isn't showed in wxpython

[lyw615]

Description of the problem: I'm completely a newcomer in wxpython.I have tried to make an simple interface showed in wxpython.But some problem are meeted.The details and codes are put on this web:https://stackoverflow.com/questions/49893460/an-simple-interface-plotted-by-matplotlib-and-cartopy-isnt-showed-in-wxpython Any resolutions are appreciated