title: Kivy Android plyer.gps on_location Callback is Never Called
body: <p>I'm writing a quick test using Kivy and Plyer to get my phone's GPS coordinates.</p>
  
  <pre><code>from kivy.app import App
  from kivy.logger import Logger
  from plyer import gps
  
  def main():
  
      app = GPSApp()
      app.run()
  
  class GPSApp(App):
  
      def on_start(self):
  
          Logger.info("Called start")
  
          gps.configure(
              on_location=self.on_location
          )
  
          gps.start()
  
      def on_location(self, **kwargs):
  
          Logger.info("Called on_location")
          Logger.info(kwargs)
  
  if __name__ == '__main__':
      main()
  </code></pre>
  
  <p>As you can see I'm calling <code>gps.conigure</code> and <code>gps.start</code> on start, passing <code>self.on_location</code> as the on_location callback. I'm logging when both the <code>on_start</code> and <code>on_location</code> methods are called, and I see the following in the log using <code>adb logcat | grep python</code>:</p>
  
  <pre><code>12-08 14:18:50.478 19290 19388 I python  : Android kivy bootstrap done. __name__ is __main__
  12-08 14:18:50.478 19290 19388 I python  : AND: Ran string
  12-08 14:18:50.478 19290 19388 I python  : Run user program, change dir and execute entrypoint
  12-08 14:18:50.537 19290 19388 I python  : [WARNING] [Config      ] Older configuration version detected (0 instead of 21)
  12-08 14:18:50.537 19290 19388 I python  : [WARNING] [Config      ] Upgrading configuration in progress.
  12-08 14:18:50.539 19290 19388 I python  : [INFO   ] [Logger      ] Record log in /data/user/0/org.test.gpstest/files/app/.kivy/logs/kivy_19-12-08_0.txt
  12-08 14:18:50.539 19290 19388 I python  : [INFO   ] [Kivy        ] v1.11.1
  12-08 14:18:50.539 19290 19388 I python  : [INFO   ] [Kivy        ] Installed at "/data/user/0/org.test.gpstest/files/app/_python_bundle/site-packages/kivy/__init__.pyc"
  12-08 14:18:50.539 19290 19388 I python  : [INFO   ] [Python      ] v3.7.1 (default, Dec  8 2019, 13:53:01) 
  12-08 14:18:50.539 19290 19388 I python  : [Clang 6.0.2 (https://android.googlesource.com/toolchain/clang 183abd29fc496f55
  12-08 14:18:50.539 19290 19388 I python  : [INFO   ] [Python      ] Interpreter at "android_python"
  12-08 14:18:50.814 19290 19388 I python  : [INFO   ] [Factory     ] 184 symbols loaded
  12-08 14:18:50.931 19290 19388 I python  : [INFO   ] [Image       ] Providers: img_tex, img_dds, img_sdl2, img_gif (img_pil, img_ffpyplayer ignored)
  12-08 14:18:50.955 19290 19388 I python  : [INFO   ] [Text        ] Provider: sdl2
  12-08 14:18:51.002 19290 19388 I python  : [INFO   ] [Window      ] Provider: sdl2
  12-08 14:18:51.019 19290 19388 I python  : [INFO   ] [GL          ] Using the "OpenGL ES 2" graphics system
  12-08 14:18:51.019 19290 19388 I python  : [INFO   ] [GL          ] Backend used &lt;sdl2&gt;
  12-08 14:18:51.019 19290 19388 I python  : [INFO   ] [GL          ] OpenGL version &lt;b'OpenGL ES 3.2 V@401.0 (GIT@2eb03ad, I4480df913d, 1564143640) (Date:07/26/19)'&gt;
  12-08 14:18:51.020 19290 19388 I python  : [INFO   ] [GL          ] OpenGL vendor &lt;b'Qualcomm'&gt;
  12-08 14:18:51.020 19290 19388 I python  : [INFO   ] [GL          ] OpenGL renderer &lt;b'Adreno (TM) 640'&gt;
  12-08 14:18:51.020 19290 19388 I python  : [INFO   ] [GL          ] OpenGL parsed version: 3, 2
  12-08 14:18:51.020 19290 19388 I python  : [INFO   ] [GL          ] Texture max size &lt;16384&gt;
  12-08 14:18:51.020 19290 19388 I python  : [INFO   ] [GL          ] Texture max units &lt;16&gt;
  12-08 14:18:51.035 19290 19388 I python  : [INFO   ] [Window      ] auto add sdl2 input provider
  12-08 14:18:51.036 19290 19388 I python  : [INFO   ] [Window      ] virtual keyboard not allowed, single mode, not docked
  12-08 14:18:51.037 19290 19388 I python  : [INFO   ] Called start
  12-08 14:18:51.069 19290 19388 I python  : [WARNING] [Base        ] Unknown &lt;android&gt; provider
  12-08 14:18:51.070 19290 19388 I python  : [INFO   ] [Base        ] Start application main loop
  12-08 14:18:51.070 19290 19388 I python  : [INFO   ] [GL          ] NPOT texture support is available
  </code></pre>
  
  <p>Clearly <code>Called start</code> is logged, so I know that that <code>self.on_location</code> is being passed to <code>gps.configure</code>. But there is no record of <code>on_location</code> being called.</p>
  
  <p>Here is my <code>buildozer.spec</code>:</p>
  
  <pre><code>[app]
  
  # (str) Title of your application
  title = GPS Test
  
  # (str) Package name
  package.name = gpstest
  
  # (str) Package domain (needed for android/ios packaging)
  package.domain = org.test
  
  # (str) Source code where the main.py live
  source.dir = .
  
  # (list) Source files to include (let empty to include all the files)
  source.include_exts = py,png,jpg,kv,atlas
  
  # (list) Source files to exclude (let empty to not exclude anything)
  #source.exclude_exts = spec
  
  # (list) List of directory to exclude (let empty to not exclude anything)
  #source.exclude_dirs = tests, bin
  
  # (list) List of exclusions using pattern matching
  #source.exclude_patterns = license,images/*/*.jpg
  
  # (str) Application versioning (method 1)
  # version.regex = __version__ = '(.*)'
  # version.filename = %(source.dir)s/main.py
  
  # (str) Application versioning (method 2)
  version = 1.0
  
  # (list) Application requirements
  requirements = plyer,kivy,python3
  
  # (str) Presplash of the application
  #presplash.filename = %(source.dir)s/data/presplash.png
  
  # (str) Icon of the application
  #icon.filename = %(source.dir)s/data/icon.png
  
  # (str) Supported orientation (one of landscape, portrait or all)
  orientation = portrait
  
  # (bool) Indicate if the application should be fullscreen or not
  fullscreen = 0
  
  
  #
  # Android specific
  #
  
  # (list) Permissions
  android.permissions = INTERNET,ACCESS_COARSE_LOCATION,ACCESS_FINE_LOCATION
  
  # (int) Android API to use
  #android.api = 14
  
  # (int) Minimum API required (8 = Android 2.2 devices)
  #android.minapi = 8
  
  # (int) Android SDK version to use
  #android.sdk = 21
  
  # (str) Android NDK version to use
  #android.ndk = 9
  
  # (bool) Use --private data storage (True) or --dir public storage (False)
  #android.private_storage = True
  
  # (str) Android NDK directory (if empty, it will be automatically downloaded.)
  #android.ndk_path =
  
  # (str) Android SDK directory (if empty, it will be automatically downloaded.)
  #android.sdk_path = 
  
  # (str) Android entry point, default is ok for Kivy-based app
  #android.entrypoint = org.renpy.android.PythonActivity
  
  # (list) List of Java .jar files to add to the libs so that pyjnius can access
  # their classes. Don't add jars that you do not need, since extra jars can slow
  # down the build process. Allows wildcards matching, for example:
  # OUYA-ODK/libs/*.jar
  #android.add_jars = foo.jar,bar.jar,path/to/more/*.jar
  
  # (list) List of Java files to add to the android project (can be java or a
  # directory containing the files)
  #android.add_src =
  
  # (str) python-for-android branch to use, if not master, useful to try
  # not yet merged features.
  #android.branch = master
  
  # (str) OUYA Console category. Should be one of GAME or APP
  # If you leave this blank, OUYA support will not be enabled
  #android.ouya.category = GAME
  
  # (str) Filename of OUYA Console icon. It must be a 732x412 png image.
  #android.ouya.icon.filename = %(source.dir)s/data/ouya_icon.png
  
  # (str) XML file to include as an intent filters in &lt;activity&gt; tag
  #android.manifest.intent_filters = 
  
  # (list) Android additionnal libraries to copy into libs/armeabi
  #android.add_libs_armeabi = libs/android/*.so
  
  # (bool) Indicate whether the screen should stay on
  # Don't forget to add the WAKE_LOCK permission if you set this to True
  #android.wakelock = False
  
  # (list) Android application meta-data to set (key=value format)
  #android.meta_data =
  
  # (list) Android library project to add (will be added in the
  # project.properties automatically.)
  #android.library_references =
  
  #
  # iOS specific
  #
  
  # (str) Name of the certificate to use for signing the debug version
  # Get a list of available identities: buildozer ios list_identities
  #ios.codesign.debug = "iPhone Developer: &lt;lastname&gt; &lt;firstname&gt; (&lt;hexstring&gt;)"
  
  # (str) Name of the certificate to use for signing the release version
  #ios.codesign.release = %(ios.codesign.debug)s
  
  
  [buildozer]
  
  # (int) Log level (0 = error only, 1 = info, 2 = debug (with command output))
  log_level = 2
  
  
  # -----------------------------------------------------------------------------
  # List as sections
  # 
  # You can define all the "list" as [section:key].
  # Each line will be considered as a option to the list.
  # Let's take [app] / source.exclude_patterns.
  # Instead of doing:
  #
  #     [app]
  #     source.exclude_patterns = license,data/audio/*.wav,data/images/original/*
  #
  # This can be translated into:
  #
  #     [app:source.exclude_patterns]
  #     license
  #     data/audio/*.wav
  #     data/images/original/*
  #
  
  
  # -----------------------------------------------------------------------------
  # Profiles
  #
  # You can extend section / key with a profile
  # For example, you want to deploy a demo version of your application without
  # HD content. You could first change the title to add "(demo)" in the name
  # and extend the excluded directories to remove the HD content.
  #
  #     [app@demo]
  #     title = My Application (demo)
  #
  #     [app:source.exclude_patterns@demo]
  #     images/hd/*
  #
  # Then, invoke the command line with the "demo" profile:
  #
  #     buildozer --profile demo android debug
  </code></pre>
  
  <p>Why is <code>self.on_location</code> never called? I believe I have the proper permission and requirements set, there are no errors in the log, and I have GPS enabled on my device. Are there any other settings I'm missing here? Am I using <code>plyer</code> incorrectly?</p>
  
  <p>I did try copy/pasting the <a href="https://github.com/kivy/plyer/tree/master/examples/gps" rel="nofollow noreferrer">example</a> and  had the same results.</p>