I think the title is pretty self-explanatory: I want to know when the fingerprint sensor on my device is being activated (usually this mean the user is now tapping his/her finger on the sensor).
I've tried looking at the list of system-wide broadcast on API 23 (in android/sdk/platforms/android-23/data/broadcast_actions.txt as specified by this question) but I didn't find any that is related to fingerprint or FingerprintManager on that matter.
The main reason why I think this feat is possible is you can actually wake-up a Nexus Imprint equipped device just by tapping on the sensor. That basically implies the device is listening for any input on the sensor at any given time, right?
I'm only interested at touch events regarding the sensor – not the fingerprint data itself.
For those who wondering, here are all API 23's system-wide broadcast as specified by the file I mentioned above:
android.app.action.ACTION_PASSWORD_CHANGED
android.app.action.ACTION_PASSWORD_EXPIRING
android.app.action.ACTION_PASSWORD_FAILED
android.app.action.ACTION_PASSWORD_SUCCEEDED
android.app.action.DEVICE_ADMIN_DISABLED
android.app.action.DEVICE_ADMIN_DISABLE_REQUESTED
android.app.action.DEVICE_ADMIN_ENABLED
android.app.action.DEVICE_OWNER_CHANGED
android.app.action.INTERRUPTION_FILTER_CHANGED
android.app.action.LOCK_TASK_ENTERING
android.app.action.LOCK_TASK_EXITING
android.app.action.NEXT_ALARM_CLOCK_CHANGED
android.app.action.NOTIFICATION_POLICY_ACCESS_GRANTED_CHANGED
android.app.action.NOTIFICATION_POLICY_CHANGED
android.app.action.PROFILE_PROVISIONING_COMPLETE
android.app.action.SYSTEM_UPDATE_POLICY_CHANGED
android.bluetooth.a2dp.profile.action.CONNECTION_STATE_CHANGED
android.bluetooth.a2dp.profile.action.PLAYING_STATE_CHANGED
android.bluetooth.adapter.action.CONNECTION_STATE_CHANGED
android.bluetooth.adapter.action.DISCOVERY_FINISHED
android.bluetooth.adapter.action.DISCOVERY_STARTED
android.bluetooth.adapter.action.LOCAL_NAME_CHANGED
android.bluetooth.adapter.action.SCAN_MODE_CHANGED
android.bluetooth.adapter.action.STATE_CHANGED
android.bluetooth.device.action.ACL_CONNECTED
android.bluetooth.device.action.ACL_DISCONNECTED
android.bluetooth.device.action.ACL_DISCONNECT_REQUESTED
android.bluetooth.device.action.BOND_STATE_CHANGED
android.bluetooth.device.action.CLASS_CHANGED
android.bluetooth.device.action.FOUND
android.bluetooth.device.action.NAME_CHANGED
android.bluetooth.device.action.PAIRING_REQUEST
android.bluetooth.device.action.UUID
android.bluetooth.devicepicker.action.DEVICE_SELECTED
android.bluetooth.devicepicker.action.LAUNCH
android.bluetooth.headset.action.VENDOR_SPECIFIC_HEADSET_EVENT
android.bluetooth.headset.profile.action.AUDIO_STATE_CHANGED
android.bluetooth.headset.profile.action.CONNECTION_STATE_CHANGED
android.bluetooth.input.profile.action.CONNECTION_STATE_CHANGED
android.bluetooth.pan.profile.action.CONNECTION_STATE_CHANGED
android.hardware.action.NEW_PICTURE
android.hardware.action.NEW_VIDEO
android.hardware.hdmi.action.OSD_MESSAGE
android.hardware.input.action.QUERY_KEYBOARD_LAYOUTS
android.intent.action.ACTION_POWER_CONNECTED
android.intent.action.ACTION_POWER_DISCONNECTED
android.intent.action.ACTION_SHUTDOWN
android.intent.action.AIRPLANE_MODE
android.intent.action.APPLICATION_RESTRICTIONS_CHANGED
android.intent.action.BATTERY_CHANGED
android.intent.action.BATTERY_LOW
android.intent.action.BATTERY_OKAY
android.intent.action.BOOT_COMPLETED
android.intent.action.CAMERA_BUTTON
android.intent.action.CONFIGURATION_CHANGED
android.intent.action.CONTENT_CHANGED
android.intent.action.DATA_SMS_RECEIVED
android.intent.action.DATE_CHANGED
android.intent.action.DEVICE_STORAGE_LOW
android.intent.action.DEVICE_STORAGE_OK
android.intent.action.DOCK_EVENT
android.intent.action.DOWNLOAD_COMPLETE
android.intent.action.DOWNLOAD_NOTIFICATION_CLICKED
android.intent.action.DREAMING_STARTED
android.intent.action.DREAMING_STOPPED
android.intent.action.EXTERNAL_APPLICATIONS_AVAILABLE
android.intent.action.EXTERNAL_APPLICATIONS_UNAVAILABLE
android.intent.action.FETCH_VOICEMAIL
android.intent.action.GTALK_CONNECTED
android.intent.action.GTALK_DISCONNECTED
android.intent.action.HEADSET_PLUG
android.intent.action.HEADSET_PLUG
android.intent.action.INPUT_METHOD_CHANGED
android.intent.action.LOCALE_CHANGED
android.intent.action.MANAGE_PACKAGE_STORAGE
android.intent.action.MEDIA_BAD_REMOVAL
android.intent.action.MEDIA_BUTTON
android.intent.action.MEDIA_CHECKING
android.intent.action.MEDIA_EJECT
android.intent.action.MEDIA_MOUNTED
android.intent.action.MEDIA_NOFS
android.intent.action.MEDIA_REMOVED
android.intent.action.MEDIA_SCANNER_FINISHED
android.intent.action.MEDIA_SCANNER_SCAN_FILE
android.intent.action.MEDIA_SCANNER_STARTED
android.intent.action.MEDIA_SHARED
android.intent.action.MEDIA_UNMOUNTABLE
android.intent.action.MEDIA_UNMOUNTED
android.intent.action.MY_PACKAGE_REPLACED
android.intent.action.NEW_OUTGOING_CALL
android.intent.action.NEW_VOICEMAIL
android.intent.action.PACKAGE_ADDED
android.intent.action.PACKAGE_CHANGED
android.intent.action.PACKAGE_DATA_CLEARED
android.intent.action.PACKAGE_FIRST_LAUNCH
android.intent.action.PACKAGE_FULLY_REMOVED
android.intent.action.PACKAGE_INSTALL
android.intent.action.PACKAGE_NEEDS_VERIFICATION
android.intent.action.PACKAGE_REMOVED
android.intent.action.PACKAGE_REPLACED
android.intent.action.PACKAGE_RESTARTED
android.intent.action.PACKAGE_VERIFIED
android.intent.action.PHONE_STATE
android.intent.action.PROVIDER_CHANGED
android.intent.action.PROXY_CHANGE
android.intent.action.REBOOT
android.intent.action.SCREEN_OFF
android.intent.action.SCREEN_ON
android.intent.action.TIMEZONE_CHANGED
android.intent.action.TIME_SET
android.intent.action.TIME_TICK
android.intent.action.UID_REMOVED
android.intent.action.USER_PRESENT
android.intent.action.WALLPAPER_CHANGED
android.media.ACTION_SCO_AUDIO_STATE_UPDATED
android.media.AUDIO_BECOMING_NOISY
android.media.RINGER_MODE_CHANGED
android.media.SCO_AUDIO_STATE_CHANGED
android.media.VIBRATE_SETTING_CHANGED
android.media.action.CLOSE_AUDIO_EFFECT_CONTROL_SESSION
android.media.action.HDMI_AUDIO_PLUG
android.media.action.OPEN_AUDIO_EFFECT_CONTROL_SESSION
android.net.conn.BACKGROUND_DATA_SETTING_CHANGED
android.net.conn.CONNECTIVITY_CHANGE
android.net.nsd.STATE_CHANGED
android.net.scoring.SCORER_CHANGED
android.net.scoring.SCORE_NETWORKS
android.net.wifi.NETWORK_IDS_CHANGED
android.net.wifi.RSSI_CHANGED
android.net.wifi.SCAN_RESULTS
android.net.wifi.STATE_CHANGE
android.net.wifi.WIFI_STATE_CHANGED
android.net.wifi.p2p.CONNECTION_STATE_CHANGE
android.net.wifi.p2p.DISCOVERY_STATE_CHANGE
android.net.wifi.p2p.PEERS_CHANGED
android.net.wifi.p2p.STATE_CHANGED
android.net.wifi.p2p.THIS_DEVICE_CHANGED
android.net.wifi.supplicant.CONNECTION_CHANGE
android.net.wifi.supplicant.STATE_CHANGE
android.nfc.action.ADAPTER_STATE_CHANGED
android.os.action.DEVICE_IDLE_MODE_CHANGED
android.os.action.POWER_SAVE_MODE_CHANGED
android.provider.Telephony.SIM_FULL
android.provider.Telephony.SMS_CB_RECEIVED
android.provider.Telephony.SMS_DELIVER
android.provider.Telephony.SMS_EMERGENCY_CB_RECEIVED
android.provider.Telephony.SMS_RECEIVED
android.provider.Telephony.SMS_REJECTED
android.provider.Telephony.SMS_SERVICE_CATEGORY_PROGRAM_DATA_RECEIVED
android.provider.Telephony.WAP_PUSH_DELIVER
android.provider.Telephony.WAP_PUSH_RECEIVED
android.speech.tts.TTS_QUEUE_PROCESSING_COMPLETED
android.speech.tts.engine.TTS_DATA_INSTALLED
