Intercept Sent text messages android

I'm creati开发者_开发问答ng a Text Encryption app, but I don't want to make a whole new text app, I just want it to handle the encryption/decryption. So I was wondering, is there a way I can somehow intercept text messages sent from an app, encrypt it, and then send it?

I know I can get the received messages, that's the easy part. But does anybody have any ideas how to get the sent messages BEFORE they are sent?

Thanks for any help!

So I was wondering, is there a way I can somehow intercept text messages sent from an app, encrypt it, and then send it?

Fortunately, this is impossible, as it would be a massive security flaw.