(please help) im having problem in my code

[boyintheroom]

Description of the Bug

1.Hi Developers im new to coding. i tried to make this video uploading app to my firebase storage but im not that good at coding so im stuck at this problem. when upload button is pressed the filechooser is opened and if i select a file it gets uploaded to the firebase But if i cancel and close the filechooser it gives an error.
2. i am unaware if this file chooser works on android or nor...if it does not please help me with this code too. im stuck on this since 6 January ,thats how poor i am.

Code and Logs

from kivy.app import App
from kivy.lang import Builder

kv = '''
<MainScreen>:
    name: 'mainscreen'
    MDLabel:
        id:username_info
        text:'Hello Main'
        font_style:'H1'
        halign:'center'

    MDFloatLayout:
        id:floate
        Video:
            id:vid

        MDToolbar:
            title: 'Bottom navigation'
            md_bg_color: .2, .2, .2, 1
            specific_text_color: 1, 1, 1, 1
        MDBottomNavigation:
            panel_color: 1,1,1,1
            MDBottomNavigationItem:
                name: 'screen 1'
                text: 'Home'
                icon: 'home-outline'
                MDRaisedButton:
                    id:upload
                    text:'Upload'
                    pos_hint:{'center_x':.5, 'center_y':.4}
                    on_release:
                        app.file_chooser()
                        upload.disabled=False
'''


class goodApp(MDApp):

    def build(self):
        self.strng = Builder.load_string(help_str)
        self.url  = "link.json"
        return self.strng

    def file_chooser(self):
        filechooser.open_file(on_selection=self.selected)        
    def selected(self,selection):
        config={
              'Api keys of firebase'
        }

        firebase=pyrebase.initialize_app(config)
        storage=firebase.storage()            
        Directory=selection[0]
        Name=re.findall('[ \w-]+\..*',Directory)
        loginEmail = self.strng.get_screen('loginscreen').ids.login_email.text
        storage.child(str(f"{loginEmail}")).child(str(f"{Name}")).put(str(f"{Name[0]}"))

        if selection==True:
            self.root.ids.vid.source=firebase
            self.strng.get_screen('mainscreen').ids.upload.disabled=True
            self.strng.get_screen('mainscreen').manager.current ='uploadscreen'
            self.strng.get_screen('mainscreen').manager.transition.direction='left'            

        if selection==False:
            self.strng.get_screen('mainscreen').ids.upload.disabled=False



if __name__ == '__main__':
    goodApp().run()

Screenshots

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Versions

• OS: win 7 pro
• Python: 3.7
• Kivy: latest
• KivyMD: latest (update everyweek)