Android programming auto sms

I have an application which sends an auto SMS when I receive an SM开发者_C百科S, or missed cal etc. So, if the same application is there in the opposite person's phone, then the the process of sending SMS continues, which should not happen. How to avoid this?

In fact, how to detect an SMS, which is sent by user or auto replied?

Please try to explain programmatically as clearly as possible..

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SmsManager sm = SmsManager.getDefault();
sm.sendTextMessage(phoneno, null,"sam", null, null);