Android QR code checker against list of codes

Android app, functions: online: - enter validation code (authorise) and download list of valid codes from server - enter validation code (authorise) and synchronize the code list (on device: add new, mark deleted; on sevrer: mark processed) remember this list when offline, even after restart... offline: - scan QR code - type code manually (if QR is not readable or other problems) - verify read/typed code against the list downloaded earlier - if code is valid (exists in the list and was not processed yet): show additional info (included in the codes list) + button to mark code as processed. processed codes should not be used again (dont use for validatioin any more). - special "search" window to search through the list and see results - here also processed are visible (and marked). ----------------------------------------------- App will be used to verify QR codes in an entrance to the event. window one: - field to enter validation code for authorisation and download/synchronize button - button to open window two (SCAN) window two (SCAN) - verification window: - at all time open camera and read QR codes. If code is read, verify against list of non-processed codes, show - WRONG CODE - CORRECT CODE + details (name) + PROCESS button if there is problem with the camera/QR, be able to enter code manually (big letters only - intelligent search, if the code starts with unique sequence, dont wait for all other letters and show the code). window three - list window: search through the list of all codes and details (name) - processed and not processed. ----------------------------------------------- must be abe to run on older android devices. must be stable for many hours of checking and processing of tickets. we dont care much about design at this stage, as simple as possible.