For all of Android's benefits and awesome features, there are still some things that it can't do and would be nice additions to the OS basic features and functionality. Locking applications for example is one thing that can't be done within Android natively. That doesn't mean that it can't be done at all, as their are a handful of applications that can get this job done for any user who is looking to lock up their applications from use by others who they may let touch and use their device. This type of function can be especially useful if you have a shared device between family members. For someone who is looking to have a more native like feel of protecting and locking up applications, there's an Xposed module that help with that.
Since this an Xposed module, there are obvious pre-requisites to using it. One your phone or device has to be rooted. Second you will need the Xposed framework installed on your device before you can install any Xposed modules, and unfortunately that also means this one. Luckily though if you already run Xposed and have a rooted device this app called PortectedApps Xposed Module is compatible with any device that is running on the software builds of Android version Jelly Bean 4.2+. That opens up the list to a wide variety of different handsets so the only setbacks one should have is not having root access or Xposed installed.
The app comes with a list of useful features for anyone who may need to lock up specific apps or system functions. It even has the ability to set parameters for unlock time duration, as well as a minimal and maximal time frame for unlocking configurable. With ProtectedApps installed you could basically have your security for the device set with the slider bard or PIN lock, but ProtectedApps could use a pattern for specific apps when wanting to unlock and use them. ProtectedApps is free, but donating will allow you to pick more than 5 apps for the lock as well as no self promotion within the application. If you're running Xposed check out the free version of the app and see how it compares to others that you might have already tried.