gistfile1.txt

here is my SimpleListAdapter that i used to override he default one:

class SimpleListAdapter(SimpleListAdapter):

    def __init__(self, **kwargs):
        super(SimpleListAdapter, self).__init__(**kwargs)
        self.args_converter=  lambda row_index, x: {'text': x,
                                                 'size_hint_y': None,
                                                 'color' : [1,1,0,1],
                                                 'text_size': (250, 25),
                                                 'font_size': 25,
                                                 'padding_x': -550,
                                                 'halign': 'left',
                                                 'height': 3

here is the kv that uses it:

MissingList:
                id: missing
                adapter: SimpleListAdapter(data= missingList(app.myAdapter.selection, 0), cls= ListItemLabel)


this works fine when i run the app, but when i use Builder.load_file to load the kv file and add it to a ScreenManager i get this error:

 BuilderException: Parser: File "grd7.kv", line 139:
 ...
     137:            MissingList:
     138:                id: missing
 >>  139:                adapter: SimpleListAdapter(data= missingList(app.myAdapter.selection, 0), cls= ListItemLabel)
     140:
     141:
 ...
 AttributeError: 'NoneType' object has no attribute 'bind'

if i comment out the adapter line it loads into the screenmanager as expected, although without the list of course. what is different?