Well basically the problem is that on android os phones anyone who takes control of that phone (ie. has any sort of access to it) has clear access to my email, messages, apps that cost money and apps that I just don't want them to use, without and request for a password or identification.
So essentially all that's needed is an app that asks you to enter an unlock pattern before you can use an app. Preferably there would also be a menu where you can see all the apps installed on your device and select which apps you would like locked.
The final package must be delivered in the apk format, along with source code. I'm unsure about what license to release the software, contact me if this is an issue.