Currently I am a student pilot in Spain (Barcelona) and I am 2 days away from my solo. I wanted to ask if there is any good application that will help me on VFR navigation since I'm allowed to go to all Barcelona in my solo, but I am afraid if I get lost I see my self weak in VFR flights and specially to locate my position so any good app in the iPhone device that will help me in navigation because I want to visit the whole Barcelona and not just staying at places that I know because I will get bored for sure.
No, there is no "app" you should be seeking at this stage of your training to do what you're asking about.
First, if you have questions about what you'll be doing while you're flying solo and how you'll be navigating, you should be discussing this with your instructor, not on an internet message board.
Second, whatever tools you'll use in flight need to be ones that you've used under supervision of an instructor, so that you understand how to use them, and what their limitations are. Student solo flying is NOT the time to go exploring technology and apps you've not used before, in addition to the full-time tasks of maintaining aircraft control, aviating, navigating, and communicating. Too many dead pilots got focused on some technological toy and, without realizing it, lost situational awareness and/or control of their aircraft.
Third, before you are navigating anywhere solo, you need to be able to (and demonstrate to your instructor that you can) navigate successfully with the tools you have -- a map, compass, stopwatch, and the pre-flight planning you've done. If you don't feel up to that task (which has been all of us early on in our training -- nobody is born with a built-in INS), work on those skills with an instructor. Navigation apps are fine, but they supplement, rather than substitute for, your own skills when it comes to VFR navigation.
Fourth, the fact that you would come here to pose such a question, rather than to your instructor, is troublesome: you want an app that can enable you to go off on adventures sightseeing all of Barcelona, but you aren't discussing these plans with your instructor... perhaps he might not approve of all that you're planning? Perhaps, maybe, you should limit your expectations of how much adventuring & exploring you'll undertake initially, and have a more complete discussion with your instructor of what you are, and are not, expected to do when, or if, you are signed off to solo. (As stated in comments, the initial solo is typically pattern work only, rather than navigation.)
Flying is about far more than aircraft control; it is a matter of judgement as well, and the difference between sound judgement and the lack of same can make the difference between a successful or a catastrophic outcome of a flight, at least as much as the difference between great and mediocre "stick & rudder" skills.
Please don't do something that you are not used to do at your first solo. First solo is always something you are waiting for, may be from the first day of your flying. So,I hope, it will not be that boring. It is not a good idea at all to depend upon a app when you are flying your 1st VFR solo. Please take enough preparation considering the terrain around your flying areas/routes. Search in Google map/earth to be very specific. Take enough preparation on the use of radio aids and diversion procedures. Be confident about emergencies. And, enjoy your solo. Good luck!!! Have a safe flight.