Use jarsigner for signing apk
ON THIS PAGE
https://developer.android.com/studio/publish/app-signing#signapp
jarsigner -verbose -keystore my-release-key.keystore -signedjar signed.apk unsign.apk alias_name
2019-04-18
https://developer.android.com/studio/publish/app-signing#signapp
jarsigner -verbose -keystore my-release-key.keystore -signedjar signed.apk unsign.apk alias_name