app always crash in android

[doomzhou]

hi folks, my app always crash after build apk
my origin example code

from kivy.app import App
from kivy.uix.scatter import Scatter
from kivy.properties import StringProperty
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.image import Image
from kivy.uix.label import Label
from kivy.properties import StringProperty

class pictures(Scatter):
    pass

class picapp(App):

    def build(self):
        App.title = "Hello"
        scatter = Scatter()
        Lab1 = Label(text="Hello world")
        scatter.add_widget(Lab1)
        root = self.root
        return scatter

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

*this is fun , but when i add my python code in it *

from kivy.app import App
from kivy.uix.scatter import Scatter
from kivy.properties import StringProperty
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.image import Image
from kivy.uix.label import Label
from kivy.properties import StringProperty

import os
import urllib
import random
from bs4 import BeautifulSoup
from uuid import uuid1



class pictures(Scatter):
    pass

class picapp(App):

    def build(self):
        App.title = "Hello"
        scatter = Scatter()
        Lab1 = Label(text="Hello world")
        scatter.add_widget(Lab1)
        root = self.root
        return scatter

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

app always crash how can i debug it ,

with kivy Launcher cannot find my code in /storage/emulated/0/kivy/pro1,
i have already pull my code to /storage/emulated/0/kivy/pro1(equal:/sdcard/kivy/pro1)

[inclement]

Follow this documentation to debug the problem.