I'm currently looking into ways to implement an Android app using Host Card Emulation in such a way that the emulated card is only active while the app is being displayed in foreground.

The default behavior seems to be that Android automatically launches the HCE service in background when it receives a SELECT command for the AID. The service can then of course just decline the SELECT however this is problematic, because if the service is not already running in background the devices take multiple seconds to respond to the SELECT.

In our scenario the user presents his device to a validator. The validator polls for the HCE AID but also for EMV Payment cards. The SELECT for the HCE app may only be successful while the app is open because otherwise it prevents using Payment cards in the Google Wallet - a multiple second delay is not really acceptable.

Any ideas how completely disabling HCE for an app in the background could be achieved?