getMacAddress() is returning null

Question

This is the code snippet that I use

public static String getMACAddressOfDevice(Context context){
        WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
        WifiInfo wifiInfo = wifiManager.getConnectionInfo();
        String macAddress = wifiInfo.getMacAddress();
        return macAddress;
    }

sometime it returns null.I don't understand why ! Can anybody explain me ?

Answer 1

When wifi is switched off , some android device returns null.

It's in current design.

If the device doesn't have wifi hardware , then this approach doesn't work.

There are some other alternatives for unique identification of devices

IMEI:

TelephonyManager TelephonyMgr = (TelephonyManager)getSystemService(TELEPHONY_SERVICE); 
String m_deviceId = TelephonyMgr.getDeviceId();

Drawbacks:

It is sim card dependent so

• If there is no sim card then we're doomed

• If there is dual sim then we're dommed

Bluetooth address:

BluetoothAdapter m_BluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); 
   String m_bluetoothAdd = m_BluetoothAdapter.getAddress();

Drawbacks:

• if there is no bluetooth hardware we're doomed.
• In future in some new devices we mightn't able to read it if its off.

Serial:

We can read the hardware serial number.It can be seen in the device settings.

 Build.SERIAL

Drawbacks:

• If the device doesn't have telephony,this can't be used.There are some wifi-only devices are available in market.

Android_ID:

You can try using the ANDROID_ID its good for unique identification of the devices since its not dependent on any hardware IMEI

String m_androidId = Secure.getString(getContentResolver(), Secure.ANDROID_ID);

Drawbacks:

• If OS version is upgraded then it may change
• If device is rooted it gets changed
• No guarantee that the device_id is unique there are some reports some manufacturers are having duplicate device_id

Suggestion:

The safest bet is to use Android_ID because it's not dependent on availability of any hardware

Reference