Create Android App that reads csv file and searches! -- 2

This app will be very simple, two screens. 1 is the Main 1 is the Update. Main: - 1 Button, 1 Phone Number Box, 1 Dropdown (for area code of the phone number). - Button when pressed will use the imported csv file to scan and find the phone number inputted. - If phone number exists, pop up "Phone number exists", if not pop up "Phone number doesnt exist) - Dropdown will have only two options for the area code (613, and 343). - Phone number when tapped will pop up with a Numeric Keypad (not text keyboard). If user enters "1119999" the output should have a dash like "111-9999". Update: - 1 Progress bar, and 1 Button - Button when pressed will download the 2 csv files from a dropbox link, and import it in the program. If the user hits update again it will delete what the program already has imported and rewrite it in. - I plan on manually reuploading the csv files on dropbox so when someone hits update it will download from same link always because my dropbox link will be same folder and file name. Just be sure to overwrite if it is existing - No update needed notification is required. Simply hit the button , download csv file into program and be able to search - Progress bar appears when download has been pushed and shows progress of the download. NOTE: There are two csv files, They are VERY large files, almost 1million phone numbers in the csv file (each line is one phone number). SO ALGORITHM SEARCHING FOR NUMBER MUST BE VERY EFFICIENT AND FAST. Images attached of example product.