So I've research this subject and I didn't get much information, even though I did read a few threads here like Check SIM PIN with SDK Android and Ask user for SIM Card PIN but neither of them really answer the question - the app I'm trying to write is based on USSD and will run on devices with SIMCards.
I also read the thread Use system PIN dialog in Android application, but I'm not trying to overwrite the OS, I'm just trying to write a simple app that can check an entered String against the SIMCard PIN. On this last thread, a user (a.ch.) said that trying to access or even check the SIMCard PIN number is not allowed by the OS (at least without modifications, I suppose). Can you guys confirm or give me a link that mentions this prohibition?
Also, is it possible to, using only USSD, check the PIN? For example, I only know the MMI code to change PIN: **04*Current PIN * New PIN * New PIN#. And this actually returns fail or sucess messages, and if I make Current PIN = New PIN, I can actually identify if the PIN I introduced is correct or not, but I see this on a text message. Does the smartphone return this info in a attribute that I can check? How can I access the return code?
I need all the help I can get :)