iOS+Android app to ask and save username+password then display a web page in a webview

Job ID: 32004448

Budget: €30 – €250 EUR

I need an app to facilitate website users accessing to a password-protected area of the website.
The requisites are mandatory:

- target at least iOS and Android platforms;
- have a login form, with option to save credentials to user's device;
- have a webview to navigate pages, opened after the login form;
- have an option to forget credentials;
- give full source code and instructions to build for the two target OSes.
- localize the app to one language of my choice, I will give you the translations.

More details on how the app should work:
1) initially, credentials are not saved;
2) if credentials are not saved, the app displays a login form with 3 fields: "username" input, "password" input, "remember credentials" checkbox, and the "login" button;
3) if clicking the login button, and "remember credentials" is checked, then credentials are saved to user's device;
4) in both cases ("remember credentials" checked or not), clicking the "login" button would open the webview with an URL like https://example.com/private/username/passwordmd5hash which is generated from the provided username and passwords, the exact format and algorithm will be told later; it should be possible to navigate additional links while remaining in the webview;
5) there should be some way for the webpage to tell the webview the credentials are incorrect (redirecting to a special URL, javascript function... you name it) so that the app will show again the login form of point 2);
6) if opening the app and credentials are saved, the app displays the webview of point 4);
7) while on the webview, there should also be an easy way to remove those, e.g. via a menu, button or dialog; removing the credentials would switch back to the login form.

This is my idea for providing an app to an already existing password-protected area of a friend's website. (I programmed the password protected area in PHP).

If you have ideas to simplify the app further, at the cost of adding some more functionality to the webpage (e.g. saving cookies, calling JS functions, etc) suggestions are welcome. I'm doing this for a friend, but I just don't have time to learn an app framework just for this task.