Block unwanted call and sms from your android app

We all get those calls we wish we didn’t, whether they are cold sales calls, SPAM, exes, or any other unwanted voice. It’s easy to see the number and then manually deny the number, but it would be nice to have an application to handle that task automatically.
TechRepublic reader Rijus asked me to how to block a call programatically in Android 2.3 (Gingerbread). Read my answer below, and then post in the comments how you block unwanted calls on Android devices.
I would quote the saying, but Apple might sue. The application I’ve used and had great success with is Call Blocker from NQ Mobile. This free application allows you to block with blacklists, allow with whitelists, block SPAM SMS, create private contacts, clear calling history, and much more. You can even block unknown calls or calls with withheld IDs.
Call Blocker will also run on phones with Eclair, Froyo, and Honeycomb. There is a premium version of the app.