Java tutorial
import android.app.IntentService; import android.content.Intent; import android.content.SharedPreferences; import android.preference.PreferenceManager; import android.util.Log; import com.google.android.gms.gcm.GoogleCloudMessaging; import com.google.android.gms.iid.InstanceID; public class GCMRegistrationService extends IntentService { private final String SENT_TOKEN = "SENT_TOKEN"; public GCMRegistrationService() { super("GCMRegistrationService"); } @Override protected void onHandleIntent(Intent intent) { super.onCreate(); SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this); try { InstanceID instanceID = InstanceID.getInstance(this); String token = instanceID.getToken(getString(R.string.gcm_defaultSenderId), GoogleCloudMessaging.INSTANCE_ID_SCOPE, null); Log.i("GCMRegistrationService", "GCM Registration Token: " + token); //sendTokenToServer(token); sharedPreferences.edit().putBoolean(SENT_TOKEN, true).apply(); } catch (Exception e) { sharedPreferences.edit().putBoolean(SENT_TOKEN, false).apply(); } } }