重启android后Python kivy应用程序空白

更新：我将.apk文件从ubuntu复制到我的android手机上，每次重启android手机时我都要安装.apk，这很无聊

所以昨天晚上，我使用buildozer在android上成功地启动了我的kivy python应用程序，它运行正常。但它不会动态更新我的android手机上的值，今天我重新启动了手机，应用程序现在是空白的。另外，请注意，我在代码中使用了kivy.urlrequest。所以我有两个问题：当应用程序打开时动态更新应用程序中的值，并且即使在重新启动我的android手机后，应用程序也应该工作

我错过了什么？请帮忙

示例代码如下：

from kivy.app import App
from kivy.uix.floatlayout import FloatLayout
from kivy.network.urlrequest import UrlRequest
from kivy.uix.label import Label
from kivy.uix.button import Button
import json
import certifi


class MainScreen(FloatLayout):
    def __init__(self, **kwargs):
        super(MainScreen, self).__init__(**kwargs)
        self.a = None            
        self.test_connection()
        print(" I am in init")

    def on_getCloudEvents_success(self,request,result):
        print("on_getCloudEvents_success called:")
        print("  result="+str(result))
        self.resp = result
        self.SYNC_REQUEST_STAT="Success" # to end the synchronous wait
        self.after_success()
        
        
    def on_getCloudEvents_failure(self,request,result):
        print("on_getCloudEvents_failure called:")
        print("  request was sent to "+str(request.url))
        print("    request body="+str(request.req_body))
        print("    request headers="+str(request.req_headers))
        print("  result="+str(request.result))
        self.SYNC_REQUEST_STAT="Failure" # to end the synchronous wait
        self.after_success()

    def on_getCloudEvents_error(self,request,result):
        print("on_getCloudEvents_error called:")
        print("  request was sent to "+str(request.url))
        print("    request body="+str(request.req_body))
        print("    request headers="+str(request.req_headers))
        print("  result="+str(request.result))        
        self.SYNC_REQUEST_STAT="Error" # to end the synchronous wait
        self.after_success()
            
      
    def after_success(self):
#        button = Button(text='Hello world'+self.a)
#        self.add_widget(button)
        self.a = "heree"
        label = Label(text='Hello from Kivy'+self.SYNC_REQUEST_STAT,
                      size_hint=(.5, .5),
                      pos_hint={'center_x': .5, 'center_y': .5},
                      color = [1.4, 1, 1, 1.8])
    
        self.add_widget(label)
        return self

        
    def test_connection(self):
        

        print(jdata)
        scan_url = 'https://scanner.tradingview.com/crypto/scan'
            UrlRequest(scan_url, ca_file = certifi.where, 
 verify=True,                    
                on_success=self.on_getCloudEvents_success,
                on_failure=self.on_getCloudEvents_failure,
            on_error=self.on_getCloudEvents_error)

class App(App):   
        
    def build(self):
        return MainScreen()
        

if __name__ == "__main__":
    App().run()