A major design flaw in the Android OS (and really virtually any OS out there) is that you cannot keep people entirely out of your device(s). While it is entirely possible that you do not care about those silly cat meme pictures that you have been downloading from the web, there are others who have more sensitive information that wandering eyes should not easily find. This is the case, for instance, when a friend asks you to borrow your phone. Now, the person likely has no time to sit around until your reorganize your device trying to keep it tidy and evidence free. Moreover, you likely don’t want to look like you are making sure your friend does not start snooping around in an attempt to keep your friendship intact. So, how do you deal with this issue?
Obstructer by XDA Forum Member obstructer is a tool that allows a user to use an Android smartphone as a (get ready) phone. Virtually every single soft/hardware button gets disabled, which prevents anyone (other than yourself of course) to get out of the dialer application. This means that no one can see your notification bar, your other apps, your menus, or even attempt at making your home screen look better. The app will work until you no longer need it to, as it requires a password to disable it, thus making your phone normal again. The dialer is a simple to use dialer (not the stock Android one), which means that none of your contacts will be displayed either.
The app seems to be a bit of a hit-or-miss according to several reviews in the Play Store. Many people are claiming that the app does not work on their devices. However, this does not mean that the app does not work at all. So, please lend the dev a helping hand and let him know your thoughts, feedback, and bugs. Also, please make sure to specify both the device and OS version that you are using in order to properly assess your scenario. You can find more information in the original thread._________