(Android 9) habe gibt die Funktion wifi.wifissid nur mehr <unknown ssid> zurück
Das geschieht, wenn Du nicht die Berechtigung hast.
Neben den poermissions im Manifest MUSS die Berechtigung zur Laufzeit ebenfalls mit Runtimepermission abgefragt werden.
https://developer.android.com/about/versions/pie/android-9.0-changes-all
Restricted access to Wi-Fi location and connection information
In Android 9, the permission requirements for an app to perform Wi-Fi scans are more strict than in previous versions. For details, see
Wi-Fi scanning restrictions.
Similar restrictions also apply to the
getConnectionInfo() method, which returns a
WifiInfo object describing the current Wi-Fi connection. You can only use this object's methods to retrieve SSID and BSSID values if the calling app has the following permissions:
- ACCESS_FINE_LOCATION or ACCESS_COARSE_LOCATION
- ACCESS_WIFI_STATE
Retrieving the SSID or BSSID also requires location services to be enabled on the device (under
Settings > Location).
Information removed from Wi-Fi service methods
In Android 9, the following events and broadcasts don't receive information about the user's location or personally identifiable data:
The
NETWORK_STATE_CHANGED_ACTION system broadcast from Wi-Fi no longer contains SSID (previously EXTRA_SSID), BSSID (previously EXTRA_BSSID), or connection information (previously EXTRA_NETWORK_INFO). If your app needs this information, call
getConnectionInfo() instead.