bitcoin transfer without creating wallet My question is about transferring bitcoin between two addresses without having a wallet.

Here is my idea of transferring bitcoins in following way:

Idea:

I have my own Android Application. I am willing to send/receive bitcoin using blockcypher Apis

I will keep private and public keys generated from above apis in my own database by encrypting it.

Does it make sense? 

This might be a stupid question to experts, but as a newbie in block-chain technology I am curious to know the right direction of the concept.
Sure, this would work.

That said, you are essentially building your own wallet - A wallet is simply a program that hold private keys, keeps track of spendable inputs, and signs transactions.

Your system achieves all of the above, so you are essentially building your own wallet.