An Android app remembers its data after uninstall and reinstall

Hi ,

Im' using plugin settings to save user Pin so when he open again the app so he will auto login .

My problem here is when I unistall the application and install it again , it does not start from zero , but there is a saved login , I know that android from

version 6 , have a func that auto backup , so I added to my manifest file those 2 lines but it didn't work . any idea ?

  <application android:allowBackup="false"/>
<application 
    android:fullBackupContent="false">
</application>