Simple iOS and Android app, editable later (full source code should be included) that counts down and displays a message from a site (obtained from an API POST call)

Hello, I need an app for iOS and Android to be published in Stores, that gets a message (like "Hello") from a site and displays a button with a message ("Start task") that starts a countdown (like 02:00:00 hrs). After pressing the button, the countdown starts running and the button becomes disabled. When it gets to 00:00:00, it stops and the button becomes enabled again. Another button at the bottom - also with a configurable message from the site - asks (in a prompt window) an Employer ID and a numeric code, that sends it to the site (via an API call). I need the source code and an easy to change and maintain app. All the values above should be configurable (in a file at the start of app, at least the URL of the site) and via an API call to the site (when the device is online). So, the app will have 2 screens: 1. a screen with header, footer, a countdown timer + 2 buttons 2. a screen with a prompt dialog box that asks 2 values from the user The app will read a JSON file from a site (which URL would be in a config file, not hardcoded) with: In screen 1. - 1 static text in header - 1 message - 2 button labels + In screen 2. - 2 textbox labels - 1 submit button label - 1 cancel button label Upon pressing submit button in the dialog box, the app sends a message to the site with Device ID + the 2 values. Please see the screenshot attached. IMPORTANT: The site (API endpoint) is NOT in scope for this project.