How to fix 'No JAR signatures' when Upload an APK in Playstore?

Question

I developed my app in Android Studio 3.4. Now I need to release the v1 of my app on playstore and I have this error:

You uploaded an APK with an invalid signature (learn more about signing). Error from apksigner: ERROR: JAR_SIG_NO_SIGNATURES: No JAR signatures

Answer 1

When exporting your APK, you need to check the V2 signature box so that google play knows that you're the one who signed it.

Answer 2

This happened to me after I changed the build variant to release and then hit the green play button and then attempted to upload the resultant apk from the auto-generated build folder.

Instead, after a clean/rebuild (which will erase that auto-generated build folder), make sure to use Build * Generate Signed APK (and check off signing for both v1 and v2). That will generate signed APKs in e.g. app/free/release. The Play Store should accept this APK. Also, go into the build folder and save the mappings from app/build/output so you can deobfuscate a stack trace from any errors that come up for your users.

(Not sure why Google doesn't save the mapping in the same folder tree as the signed APK...)