According do developers there's no need to close DB connection. SQLiteOpenHelper will do it for us. Here are some proofs:
- https://groups.google.com/forum/?fromgroups#!msg/android-developers/nopkaw4UZ9U/cPfPL3uW7nQJ
- http://stackoverflow.com/questions/4842112/when-to-close-db-connection-on-android-every-time-after-your-operation-finished