I want to upload my kivy application to Google Play store. For that i Need an .apk file , which has an api Level of 26 or higher. The .apk that I created had an apk Level of 19. So this was my way to set the Level to 26:
I installed API 26,27,28 and the newest version of the building tool. 
In buildozer.spec i set android.api = 26.
After that I run "buildozer android release deploy run". And now I get this error:
"Check that aidl can be executed 
Search for Aidl 
Run 'home/dennis/.buildozer/android/platform/android-sdk-20/build-tools/28.0.2/aidl' 
CWD None
Aidl cannot be executed"
What can i do to fix this? 
Thank you!
Run ~/.buildozer/android/platform/android-sdk-20/tools/android
Select Android SDK Build-tools 26.x.x
Check aidl file in ~/.buildozer/android/platform/android-sdk-20/build-tools/26.x.x/
Create kivy apk with buildozer ERROR: "Aidl cannot be executed"