2014-03-06 12:26 GMT+01:00 Andreas Schildbach <andreas@schildbach.de>:


> In current phone implementations, the screen must be on already for NFC
> to be active. Also it must be unlocked, although I certainly hope future
> OSes will allow payment apps on the lock screen, just like they allow
> music players.


Just a small input to this point:
On Android 4.4 the new host card emulation (HCE) feature (aka: the phone
emulates a ISO-DEP Smartcard and processes ISO7816-4 APDU commands like a
Smartcard would do) only works when the display is on, but even when the
screen is locked (can be changed with "android:requireDeviceUnlock" in
Manifest). See here for detailled specification:
http://developer.android.com/guide/topics/connectivity/nfc/hce.html

Using the HCE API on Android 4.4 also has the beauty that any app that
registers itself for HCE and sets its category to CATEGORY_PAYMENT in the
Manifest automatically shows up in Adroid's system settings under "Tap &
Pay" (where a user would expect payment applications).