This one won’t be root-only for long. I remember about a year ago there was an explosion of call-blocking apps for BlackBerry. They all functioned differently in terms of specifics, but they all accomplished the same end, which was to prevent unwanted callers from reaching your phone. That influx will likely come for Android phones soon enough. Over the weekend I saw one at xda. It’s root only, so it won’t be available to everyone. But for those with rooted phones who want to keep away unwanted calls, this one is a must-install.
The difference between this app and others is in the first line of the marketing material: “calls are rejected before your phone connects!” Apparently, then, other call-rejecting apps only work after the call connects and your phone starts ringing. Not being an expert on this particular app niche for Android, I’m not sure how true that is, so I’ll refrain from comment. I will say that this is the only worthwhile way a call-rejecting app can work. Maybe you can find marginal value in rejecting a call once it connects, but the bulk of the value is in cutting it off before it even starts.
If you so choose, the app can completely block unknown or blocked numbers. Again, you can just not pick these up, but Root Call Blocker cuts them off even before that point. I never want to pick up calls like that, but sometimes curiosity gets the better of me. In that way, this app acts like automated self control. You can see the calls later, of course, but if they’re blocked or unknown, it won’t make much of a difference.
To make ti even more user-friendly, the app has the ability to create white and black lists. That is, you can add unwanted contacts to a blacklist, and they’ll be sent to the rejection pile. Alternatively, you can create a white list of allowed callers, sending everyone else to the scrap heap. You can choose a reply to these rejected numbers, though there is the always simple “don’t answer.” I like that one plenty. That is, unless you have a specific blacklist of people you don’t want calling, but you still want to give the courtesy of an explanation.
The app is still in beta, so there are bugs. If you check out the xda thread, you can see that plenty of work has gone into correcting these issues. If you’re rooted and want to give this one a try, you can download Root Call Blocker for free from the Market.