question: private void cancelNotifications ( ) { final NotificationManager nm = ( NotificationManager ) getSystemService ( NOTIFICATION_SERVICE ) ; nm . cancel ( NOTIFICATION_ID ) ; final List < BluetoothDevice > managedDevices = getManagedDevices ( ) ; for ( final BluetoothDevice device : managedDevices ) { nm . cancel ( device . getAddress ( ) , NOTIFICATION_ID ) ; } }
target:  Cancels the existing notification. If there is no active notification this method does nothing