Database won't remove when uninstall the Android Application

Question

I have two major questions.

1. Database won\'t delete when uninstall app.
2. Downloaded files won\'t delete while unstable the app.

There is a d

Answer 1

in Android 6.0, google added new feature called Auto Backup.

when this option is on(default is on), Android system copies almost every directories and files that created by system, and upload it to user's google drive account.

When user reinstalls app, android automatically restore app's data, no matter how it was installed(via Play store, adb install, initial device setup).

The restore operation occurs after the APK is installed, but before the app is available to be launched by the user.

android developers page : https://developer.android.com/guide/topics/data/autobackup.html