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To change the appearance of those various functions, you're probably best off searching for alternate apps that allow you to do so. Search Google Play for dialer, contacts, and calculator apps, and see if you like them better.
If you installed Exdialer and then didn't like it, you could uninstall it easily, and the phone would revert back to the stock dialer.
Google Play is generally very safe, and Google scans all apps that you install, which adds an extra layer of protection. But it's true, sometimes shady apps sneak into Google Play--so read through the reviews first, and see if there are any warning signs from other users. Be cautious about apps that have very few downloads, or overly rosy reviews (which might be fake). And if an app sounds too good to be true (like an app that promises free movies or something like that), then it probably is.
06-22-2014 12:38 PM