Password Protected App

I have created an android application but I don't want una开发者_运维技巧uthorized persons to access and use my application. How can I make my application a password protected?

One solution you can use is, give your users an user id and password after registering them and let them login the first time they start your app. Associate the device id (unique) with the user id (during the registration phase) and check for this device id when the user is logging in. For the authentication you will need a web service.