Develop Reference

Why I am getting JsonSyntaxException Error

I am new to retrofit (I was using volley before), before this I was doing fine with retrofit until this error comes :-
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException:
Expected int but was Boolean at line 8 column 37 path
$.response.data.book_service_id
I tried with every solution provided in this site but could not help myself since I am new to retrofit.
I think it's because of the JSON parsing error. I don't know how to handle it.
This may be a duplicate question but please help.
Below is my code:
Request and fetching data:
private void makeBookingRequest(String position) {
final CustomProgressDialog dialog = new CustomProgressDialog();
dialog.show(getSupportFragmentManager(),"tag");
SharedPreferences preferences = getSharedPreferences("MYSharedPref",MODE_PRIVATE);
String sessionkey = preferences.getString("sessionkey",null);
System.out.println(sessionkey);
String serviceId = position;
System.out.println(position);
APIEndPoints endPoints = Url.getInstance().create(APIEndPoints.class);
Call<Book> call = endPoints.makeBookingRequest(serviceId,sessionkey);
call.enqueue(new Callback<Book>() {
#Override
public void onResponse(Call<Book> call, retrofit2.Response<Book> response) {
dialog.dismiss();
if (!response.isSuccessful()) {
Toast.makeText(HomeActivity.this, "server is not responding", Toast.LENGTH_SHORT).show();
}
else if(response.body() != null){
Book bookData = response.body();
String message = bookData.response.message;
Toast.makeText(HomeActivity.this, message, Toast.LENGTH_SHORT).show();
}
}
#Override
public void onFailure(Call<Book> call, Throwable t) {
dialog.dismiss();
Toast.makeText(HomeActivity.this, "Error" + t.getLocalizedMessage(),
Toast.LENGTH_SHORT).show();
System.out.println(t);
}
});
}
Model Class:
package com.medpal.medpal_client.Models;
import com.google.gson.annotations.SerializedName;
public class Book {
#SerializedName("response")
public ResponseEntity response;
public class ResponseEntity{
#SerializedName("data")
public DataEntity data;
#SerializedName("secondary_message")
public String secondary_message;
#SerializedName("message")
public String message;
#SerializedName("code")
public int code;
}
public class DataEntity {
#SerializedName("book_service_id")
public int book_service_id;
}
}
APIENDPOINTS
#FormUrlEncoded
#Headers({"apikey: testapikey", "Content-Type:application/x-www-form-urlencoded" })
#POST("service/accept?")
Call<Book> makeBookingRequest(
#Field("service_id") String ServiceId,
#Field("session_key") String sessionKey);
URL class
public class Url {
public static final String base_url = "http://www.medpal.net/api/v1/";
public static final String serviceUrl = "http://www.medpal.net/api/v1/services?";
public static Retrofit retrofit;
public static Retrofit getInstance() {
if (retrofit == null) {
retrofit = new Retrofit.Builder()
.baseUrl(base_url)
.addConverterFactory(GsonConverterFactory.create())
.build();
}
return retrofit;
}
}
Finallyy Response from server:
{
"response": {
"error": [],
"code": 200,
"message": "Service booked",
"secondary_message": "Service booked successfully",
"data": {
"book_service_id": 35
}
}
}

To detect the problem exactly, You need to use an interceptor to log the server response, to log the server responses you can use OkHttp3 here is an example of it.
private OkHttpClient provideOkhttpClient() {
OkHttpClient.Builder client = new OkHttpClient.Builder();
client.readTimeout(15000, TimeUnit.MILLISECONDS);
client.writeTimeout(70000, TimeUnit.MILLISECONDS);
HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
client.addInterceptor(interceptor);
return client.build();
}
And add this to your Retrofit.Builder
.client(provideOkhttpClient())
And these are for Gradle
implementation 'com.squareup.okhttp3:okhttp:3.12.0'
implementation 'com.squareup.okhttp3:logging-interceptor:3.5.0'
If you do this you will see everything you sent and got from the server at your Logcat.

Retrofit: Redirect to LoginActivity if response code is 401

How to start LoginActivity from the interceptor(non-activity class)? I have tried the code (Interceptor) below but not working for me.
Interceptor
OkHttpClient client = new OkHttpClient.Builder().addInterceptor(new Interceptor() {
#Override
public Response intercept(Chain chain) throws IOException {
Request newRequest = chain.request().newBuilder()
.addHeader("Authorization", "Bearer " + auth_token_string)
.build();
Response response = chain.proceed(newRequest);
Log.d("MyApp", "Code : "+response.code());
if (response.code() == 401){
Intent intent = new Intent(SplashActivity.getContextOfApplication(), LoginActivity.class);
startActivity(intent);
finish(); //Not working
return response;
}
return chain.proceed(newRequest);
}
}).build();
This is the current solution I'm using, is there any better solution than this? This solution has to keep repeat on every api call.
MainActivity
call.enqueue(new Callback<Token>() {
#Override
public void onResponse(Call<Token> call, Response<Token> response) {
if(response.isSuccessful())
{
//success
}
else
{
Intent intent = new Intent(MainActivity.this.getApplicationContext(), LoginActivity.class);
startActivity(intent);
finish();
}
}
#Override
public void onFailure(Call<Token> call, Throwable t) {
}
});

Personally, I would like to suggest using event bus pattern here. You can use greenrobot implementation or whatever you want, since it's more about an architecture approach rather than concrete implementation.
Create event model
public class UnauthorizedEvent {
private static final UnauthorizedEvent INSTANCE = new UnauthorizedEvent();
public static UnauthorizedEvent instance() {
return INSTANCE;
}
private UnauthorizedEvent() {
}
}
Implement custom Interceptor which disptaches event about unauthorized reqeusts
class UnauthorizedInterceptor implements Interceptor {
#Override
public Response intercept(#NonNull Chain chain) throws IOException {
Response response = chain.proceed(chain.request());
if (response.code() == 401) {
EventBus.getDefault().post(UnauthorizedEvent.instance());
}
return response;
}
}
Create BaseActivity class which handles UnauthorizedEvent
public class BaseActivity extends Activity {
#Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
#Override
public void onStop() {
super.onStop();
EventBus.getDefault().unregister(this);
}
#Subscribe
public final void onUnauthorizedEvent(UnauthorizedEvent e) {
handleUnauthorizedEvent();
}
protected void handleUnauthorizedEvent() {
Intent intent = new Intent(this, LoginActivity.class);
startActivity(intent);
}
}
Prevent launching LoginActivity from LoginActivity
public class LoginActivty extends BaseActivity {
#Override
protected void handleUnauthorizedEvent() {
//Don't handle unauthorized event
}
}
Another approach is to not extending BaseActivity here.
Register your interceptor
OkHttpClient client = new OkHttpClient.Builder()
.addInterceptor(new UnauthorizedInterceptor())
.build();
Pros:
Loose coupling between components
Easaly extending the logic by overriding handleUnauthorizedEvent
No need to rewrite code to use new types of callbacks
Reduce human factor about making mistakes (using Callback instead of BaseCallback)
Cons:
EventBus pattern makes debugging more complicated
One more dependency or own implementation which brings new code to the project
Also, please take into account, that this example doesn't cover multithreading issues. It solves your problem of handling unauthorized requests. Thus, if two requests receive 401 than it is possible that 2 instances of LoginActivity is started.

Consider introducing a custom implementation of retrofit2.Callback interface, e.g. BaseCallback:
public abstract class BaseCallback<T> implements Callback<T> {
private final Context context;
public BaseCallback(Context context) {
this.context = context;
}
#Override
public void onResponse(Call<T> call, Response<T> response) {
if (response.code() == 401) {
// launch login activity using `this.context`
} else {
onSuccess(response.body());
}
}
#Override
public void onFailure(Call<T> call, Throwable t) {
}
abstract void onSuccess(T response);
}
Now, from the caller site you should change new Callback<Token> with new BaseCallback<Token>:
call.enqueue(new BaseCallback<Token>(context) {
#Override
void onSuccess(Token response) {
// do something with token
}
});
Although, this approach doesn't fulfil your following statement:
so I don't have to keep repeat the same code over again for each api call
nevertheless, I cannot come up with a better approach.

The simplest way is to inject activity context in Interceptor instance.
If you are using some DI tools, like Dagger2 or Toothpick it will be very simple. I recommend to use toothpick)
https://github.com/stephanenicolas/toothpick
The most code near by will be in kotlin, because it's my boilerplate code. Those thinks, that you are need to solve your problem i will write in Java.
The solution will be like this:
#Qualifier
annotation class BackendUrl
class ActivityModule(activity: BaseActivity): Module() {
init {
bind(Activity::class.java).toInstance(activity)
}
}
class NetworkModule: Module() {
init {
bind(String::class.java).withName(BackendUrl::class.java).toInstance(Constants.URL)
bind(Gson::class.java).toInstance(GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ss").create())
bind(CacheHolder::class.java).toProvider(CacheProvider::class.java).singletonInScope()
bind(OkHttpClient::class.java).toProvider(OkHttpProvider::class.java).instancesInScope()
bind(BackendApi::class.java).toProvider(BackendApiProvider::class.java).instancesInScope()
bind(RedirectInterceptor::class.java).to(RedirectInterceptor::class.java)
}
}
Than you need to create Providers for injection dependency
class BackendApiProvider #Inject constructor(
private val okHttpClient: OkHttpClient,
private val gson: Gson,
#BackendUrl private val serverPath: String
) : Provider<BackendApi> {
override fun get() =
Retrofit.Builder()
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(okHttpClient)
.baseUrl(serverPath)
.build()
.create(BackendApi::class.java)
}
And your redirect interceptor:
public class RedirectInterceptor implements Interceptor {
private final Context context;
#Inject
public RedirectInterceptor(Activity context) {
this.context = context;
}
#Override
public Response intercept(Chain chain) throws IOException {
Request newRequest = chain.request().newBuilder()
.build();
Response response = chain.proceed(newRequest);
Log.d("MyApp", "Code : "+response.code());
if (response.code() == 401){
Intent intent = new Intent(context, LoginActivity.class);
context.startActivity(intent);
((Activity) context).finish();
return response;
}
return chain.proceed(newRequest);
}
}
Oh, yes. For Authorization header will be better to create new instance of another interceptor
class HeaderInterceptor(private val token: String?) : Interceptor {
#Throws(IOException::class)
override fun intercept(chain: Interceptor.Chain): Response {
val request = chain.request()
val newRequest = request.newBuilder()
Log.d(TAG, "token: $token")
if (token != null && token.isNotBlank()) {
newRequest.addHeader("Authorization", "Bearer $token")
}
return chain.proceed(newRequest.build())
}
companion object {
private val TAG = HeaderInterceptor::class.java.toString()
}
}
And your OkhttpProvder
class OkHttpProvider #Inject constructor(cacheHolder: CacheHolder, prefs: IPreferences, redirectInterceptor: RedirectInterceptor) : Provider<OkHttpClient> {
private val client: OkHttpClient
init {
val builder = OkHttpClient.Builder()
builder
.addNetworkInterceptor(redirectInterceptor)
.addNetworkInterceptor(HeaderInterceptor(prefs.getAuthToken()))
.readTimeout(30, TimeUnit.SECONDS)
.cache(cacheHolder.okHttpCache)
client = builder.build()
}
override fun get() = client
}
Thats all! Now, you just only need to place you modules in right scopes.
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.init_view)
Toothpick.openScopes("activity scope").apply {
installModules(ActivityModule(this#YourActivity))
Toothpick.inject(this#YourActivity, this)
}
Toothpick.openScopes("activity scope", "network scope").apply {
installModules(NetworkModule())
}
// your activity code
}

This is how interceptor worked for handling 401 globally
public class ResponseHeaderInterceptor implements Interceptor {
private final Context context;
public ResponseHeaderInterceptor(Context context) {
this.context = context;
}
#NotNull
#Override
public Response intercept(#NotNull Chain chain) throws IOException {
Response response = chain.proceed(chain.request());
if(response.code() == 401){
SharedPreferences pref = context.getSharedPreferences(Constants.PREFERENCES, 0);
String userName = pref.getString("key_user_email", "");
//clear shared preferences
pref.edit().clear().apply();
Bundle params = new Bundle();
params.putString("user", userName);
FirebaseAnalytics.getInstance(context).logEvent(Constants.USER_UNAUTHORIZED_EVENT, params);
Intent intent = new Intent(this.context, IntroActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
this.context.startActivity(intent);
}
return response;
}
}
adding to okhttp client of retrofit
var okHttpClient: OkHttpClient = OkHttpClient()
.newBuilder()
.addInterceptor(ResponseHeaderInterceptor(MyApplication.getMyApplicationContext()))//Header interceptor for logging network responses
.build()
private var retrofit: Retrofit? = null
val client: Retrofit?
get() {
if (retrofit == null) {
retrofit = Retrofit.Builder()
.client(okHttpClient)
.baseUrl(BuildConfig.SERVER)
.addConverterFactory(GsonConverterFactory.create())
.build()
}
return retrofit
}

Generalized Solution:
You can solve it by generalizing the error handling. You can use custom CallAdapterFactory to the Retrofit builder. Please refer below classes :
RxErrorHandlingCallAdapterFactory :
public class RxErrorHandlingCallAdapterFactory extends CallAdapter.Factory {
private static Context mContext = null;
private final RxJava2CallAdapterFactory original;
private RxErrorHandlingCallAdapterFactory() {
original = RxJava2CallAdapterFactory.create();
}
public static CallAdapter.Factory create(Context context) {
mContext = context;
return new RxErrorHandlingCallAdapterFactory();
}
#Override
public CallAdapter<?, ?> get(Type returnType, Annotation[] annotations, Retrofit retrofit) {
return new RxCallAdapterWrapper(retrofit, original.get(returnType, annotations, retrofit));
}
private static class RxCallAdapterWrapper<R> implements CallAdapter<R, Object> {
private final Retrofit retrofit;
private final CallAdapter<R,
Object> wrapped;
public RxCallAdapterWrapper(Retrofit retrofit, CallAdapter<R, Object> wrapped) {
this.retrofit = retrofit;
this.wrapped = wrapped;
}
#Override
public Type responseType() {
return wrapped.responseType();
}
#Override
public Object adapt(Call<R> call) {
Object result = wrapped.adapt(call);
if (result instanceof Single) {
return ((Single) result).onErrorResumeNext(new Function<Throwable, SingleSource>() {
#Override
public SingleSource apply(#NonNull Throwable throwable) throws Exception {
return Single.error(asRetrofitException(throwable));
}
});
}
if (result instanceof Observable) {
return ((Observable) result).onErrorResumeNext(new Function<Throwable, ObservableSource>() {
#Override
public ObservableSource apply(#NonNull Throwable throwable) throws Exception {
return Observable.error(asRetrofitException(throwable));
}
});
}
if (result instanceof Completable) {
return ((Completable) result).onErrorResumeNext(new Function<Throwable, CompletableSource>() {
#Override
public CompletableSource apply(#NonNull Throwable throwable) throws Exception {
return Completable.error(asRetrofitException(throwable));
}
});
}
return result;
}
private RetrofitException asRetrofitException(Throwable throwable) {
// We had non-200 http error
Log.v("log", "eror");
throwable.printStackTrace();
if (throwable instanceof HttpException) {
HttpException httpException = (HttpException) throwable;
final Response response = httpException.response();
//if ((mContext instanceof Activity)) {
String s = "Something went wrong."; //mContext.getString(R.string.something_went_wrong);
try {
s = new JSONObject(response.errorBody().string()).getString("message");
if (response.code() == 401) { // 401 Unauthorized
Intent intent = new Intent(mContext, LoginActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
mContext.startActivity(intent);
}
} catch (JSONException | IOException e) {
e.printStackTrace();
}
return RetrofitException.unexpectedError(s, response, retrofit);
//showErrorDialog(mContext, response);
//}
// return RetrofitException.httpError(response.errorBody().toString(), response, retrofit);
}
// A network error happened
if (throwable instanceof IOException) {
return RetrofitException.networkError((IOException) throwable);
}
// We don't know what happened. We need to simply convert to an unknown error
return RetrofitException.unexpectedError(throwable);
}
}
}
RetrofitException :
public class RetrofitException extends RuntimeException {
private final String url;
private final Response response;
private final Kind kind;
private final Retrofit retrofit;
RetrofitException(String message, String url, Response response, Kind kind, Throwable exception, Retrofit retrofit) {
super(message, exception);
this.url = url;
this.response = response;
this.kind = kind;
this.retrofit = retrofit;
}
public static RetrofitException httpError(String url, Response response, Retrofit retrofit) {
String message = response.code() + " " + response.message();
return new RetrofitException(message, url, response, Kind.HTTP, null, retrofit);
}
public static RetrofitException networkError(IOException exception) {
return new RetrofitException(exception.getMessage(), null, null, Kind.NETWORK, exception, null);
}
public static RetrofitException unexpectedError(Throwable exception) {
return new RetrofitException(exception.getMessage(), null, null, Kind.UNEXPECTED, exception, null);
}
public static RetrofitException unexpectedError(String s, Response response, Retrofit retrofit) {
return new RetrofitException(s, null, null, Kind.UNEXPECTED, null, null);
}
/**
* The request URL which produced the error.
*/
public String getUrl() {
return url;
}
/**
* Response object containing status code, headers, body, etc.
*/
public Response getResponse() {
return response;
}
/**
* The event kind which triggered this error.
*/
public Kind getKind() {
return kind;
}
/**
* The Retrofit this request was executed on
*/
public Retrofit getRetrofit() {
return retrofit;
}
/**
* HTTP response body converted to specified {#code type}. {#code null} if there is no
* response.
*
* #throws IOException if unable to convert the body to the specified {#code type}.
*/
public <T> T getErrorBodyAs(Class<T> type) throws IOException {
if (response == null || response.errorBody() == null) {
return null;
}
Converter<ResponseBody, T> converter = retrofit.responseBodyConverter(type, new Annotation[0]);
return converter.convert(response.errorBody());
}
/**
* Identifies the event kind which triggered a {#link RetrofitException}.
*/
public enum Kind {
/**
* An {#link IOException} occurred while communicating to the server.
*/
NETWORK,
/**
* A non-200 HTTP status code was received from the server.
*/
HTTP,
/**
* An internal error occurred while attempting to execute a request. It is best practice to
* re-throw this exception so your application crashes.
*/
UNEXPECTED
}
}
Retrofit Builder :
Retrofit retrofit = new Retrofit.Builder()
.addCallAdapterFactory(RxErrorHandlingCallAdapterFactory.create(context))
.addConverterFactory(GsonConverterFactory.create())
.baseUrl(API_URL)
.client(client)
.build();
You can handle 401 in RxErrorHandlingCallAdapterFactory and other errors through Throwable.

How to change the Boolean value from Retrofit onResponse method

public Boolean getOtp(String mobile, String otp, String accessToken){
Boolean success = false;
progress.setVisibility(View.VISIBLE);
progress.animate();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(getResources().getString(R.string.baseURL))
.addConverterFactory(GsonConverterFactory.create())
.build();
APIService apiService = retrofit.create(APIService.class);
Call<statusResponse> call = apiService.checkOtp(mobile,accessToken , otp);
call.enqueue(new Callback<statusResponse>() {
#Override
public void onResponse(Response<statusResponse> response, Retrofit retrofit) {
progress.setVisibility(View.INVISIBLE);
statusResponse sp = response.body();
if (sp.getStatus().equals("1")) {
success = true;
Log.e("Response ", sp.getText() + valueOf(success);
} else {
Log.e("Response Failed", String.valueOf(sp));
/*Snackbar.make(cl, "Failed to update, please try again", Snackbar.LENGTH_LONG).show();*/
}
}
#Override
public void onFailure(Throwable t) {
}
});
return success;
}
Boolean was showing error to declare it as final
final Boolean[] success = {false};
return success[0]
Then it is returning false every time.
response is
{"status":"1","text":"OTP successfull"}

You are making an asynchronous call. The onResponse method will be executed only when the call is finished. Your return success statement is executed long before that and therefore returns false.

Android, how to initiate realm in AsyncTask?

I have an asyncTask in my application as below. I have to fetch data from realm(which is successfully stored in another activity) into this AsyncTask. Below is my AsyncTask code:
public class MakeAsyncRequest extends AsyncTask<Object, String, MakeAsyncRequest.ResponseDataType>{
public Context asyncContext;
private MakeAsyncRequest(Context context){
asyncContext = context;
}
private static final OkHttpClient client = new OkHttpClient();
private static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");
private MakeRequest.ResponseHandler handler;
private String method;
private User user;
private Realm realm;
class ResponseDataType
{
InputStream inputStream;
String string;
String cookie;
}
MakeAsyncRequest(MakeRequest.ResponseHandler responseHandler, String type)
{
method = type;
handler = responseHandler;
}
#Override
protected ResponseDataType doInBackground(Object... params) {
try {
Requests requests = new Requests((Context) params[0]);
String url = params[1].toString();
String bodyJson = null;
if(method.equals("PUT") || method.equals("POST")) {
bodyJson = params[2].toString();
}
final Request.Builder builder;
Response response;
RequestBody body;
switch (method) {
case "GET": builder = new Request.Builder().url(url);
break;
case "DOWNLOAD": builder = new Request.Builder().url(url);
break;
case "POST": body = RequestBody.create(JSON, bodyJson);
builder = new Request.Builder()
.url(url)
.post(body)
.addHeader("Cookie", "key=value");
break;
case "PUT": body = RequestBody.create(JSON, bodyJson);
builder = new Request.Builder()
.url(url)
.put(body);
break;
default: builder = new Request.Builder().url(url);
}
builder.addHeader("Accept", "application/json");
realm = RealmController.initialize(this).getRealm();
final RealmResults<User> users = realm.where(User.class).findAllAsync();
user = users.first();
if(user.getCookie() !== null && !user.getCookie().isEmpty()){
builder.addHeader("cookie", "user.getCookie()");
}
response = client.newCall(builder.build()).execute();
ResponseDataType responseDataType = new ResponseDataType();
if(method.equals("DOWNLOAD")) { responseDataType.inputStream = response.body().byteStream(); }
else {
responseDataType.string = response.body().string();
responseDataType.cookie = response.headers().get("set-cookie");
CookieManager cManager = new CookieManager(null, CookiePolicy.ACCEPT_ALL);
cManager.getCookieStore().getCookies();
}
return responseDataType;
} catch (IOException e) {
return null;
}
}
#Override
protected void onPostExecute(ResponseDataType response) {
try {
if (method.equals("DOWNLOAD")) {
handler.onFinishCallback(response.inputStream);
}else {
handler.onFinishCallback(response.string, response.cookie);
CookieManager cManager = new CookieManager(null, CookiePolicy.ACCEPT_ALL);
cManager.getCookieStore().getCookies();
}
}catch (Exception e){
Log.d("hExceptionError", e.toString());
handler.onFinishCallback("{\n" +
" \"error\": \"error\"\n" +
"}","");
}
}
I am received the access error - "Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created." whenever the control tries to execute the Realm results or to get the first object from Realm.
Below is my RealmController which i created to control the realm instance:
public class RealmController {`public static RealmController initialize(Activity activity) {
if (instance == null) {
instance = new RealmController(activity.getApplication());
}
return instance;
}
public static RealmController initialize(MakeAsyncRequest activity) {
if (instance == null) {
instance = new RealmController(activity.);
}
return instance;
}
}`
I have my user model(Realm object) with setters and getters.

The point is - you cannot create and access Realm on different threads, i.e. create Realm instance in Activity and use it in .doInBackground() method. Create and release Realm immediately before and after transaction.
There may be another issue - don't register quer observer on background thread in AsyncTask - it doesn't have Looper initialized - use main thread or HandlerThread.
Release realm after it is no longer needed (you didn't in your code), because Realm has limited number of instances.

You can initiate a Realm instance in the doInBackground method of your AsyncTask like this:
private class MyAsyncTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... voids) {
Realm realm = Realm.getDefaultInstance();
// Do your Realm work here
realm.close();
return null;
}
}
It's important to note that you should always open and close a Realm instance in the same thread. In this case, since the AsyncTask is running in a background thread, you can open and close the Realm instance within the doInBackground method.

GCM Notification Receiver/Token Registration

EDIT: Figured it out -- see answer below
I'm attempting to generate registration tokens, store them in a server, and then use the tokens to send push notifications. At this point, I've successfully sent and stored registration tokens and am sending notifications from a web API, but they aren't arriving to my device. I was wondering if/what I should replace R.string.gcm_defaultSenderId with (i.e. the sender key from GCM?) I'm including my code for token registration as well as my notification listener below.
public class GCMRegistrationIntentService extends IntentService {
//Constants for success and errors
public static final String REGISTRATION_SUCCESS = "RegistrationSuccess";
public static final String REGISTRATION_ERROR = "RegistrationError";
private Context context;
private String sessionGUID = "";
private String userGUID = "";
//Class constructor
public GCMRegistrationIntentService() {
super("");
}
#Override
protected void onHandleIntent(Intent intent) {
context = getApplicationContext();
sessionGUID = RequestQueueSingleton.getInstance(context).getSessionGUID();
userGUID = RequestQueueSingleton.getInstance(context).getUserGUID();
//Registering gcm to the device
registerGCM();
}
//Registers the device to Google Cloud messaging and calls makeAPICall to send the registration
//token to the server
private void registerGCM() {
//Registration complete intent initially null
Intent registrationComplete;
//declare a token, try to find it with a successful registration
String token;
try {
//Creating an instanceid
InstanceID instanceID = InstanceID.getInstance(this);
//Getting the token from the instance id
token = instanceID.getToken(getString(R.string.gcm_defaultSenderId),
GoogleCloudMessaging.INSTANCE_ID_SCOPE, null);
//Display the token, need to send to server
Log.w("GCMRegIntentService", "token:" + token);
String android_id = Settings.Secure.getString(context.getContentResolver(),
Settings.Secure.ANDROID_ID);
int osTypeCode = Constants.OST_ANDROID;
JSONObject parms = new JSONObject();
try {
parms.put("deviceID", android_id);
parms.put("OSTypeCode", osTypeCode);
parms.put("token", token);
} catch (JSONException e) {
e.printStackTrace();
}
Transporter oTransporter = new Transporter(Constants.TransporterSubjectUSER,
Constants.REGISTER_NOTIFICATION_TOKEN, "", parms, userGUID, sessionGUID);
oTransporter.makeAPICall(getApplicationContext(), "");
//on registration complete. creating intent with success
registrationComplete = new Intent(REGISTRATION_SUCCESS);
//Putting the token to the intent
registrationComplete.putExtra("token", token);
} catch (Exception e) {
//If any error occurred
Log.w("GCMRegIntentService", "Registration error");
registrationComplete = new Intent(REGISTRATION_ERROR);
}
//Sending the broadcast that registration is completed
LocalBroadcastManager.getInstance(this).sendBroadcast(registrationComplete);
}
}
And the listener service:
public class GCMPushReceiverService extends GcmListenerService {
private static final String TAG = "GCMPushReceiverService";
//with every new message
#Override
public void onMessageReceived(String from, Bundle data){
System.out.println("WE'VE RECIEVED A MESSAGE");
String message = data.getString("message");
Log.d(TAG, "From: " + from);
Log.d(TAG, "Message: " + message);
sendNotification(message);
}
private void sendNotification(String message) {
Intent intent = new Intent(this, LogInPage.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
int requestCode = 0;
PendingIntent pendingIntent =
PendingIntent.getActivity(this, requestCode, intent, PendingIntent.FLAG_ONE_SHOT);
Uri sound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
NotificationCompat.Builder noBuilder = new NotificationCompat.Builder(this);
noBuilder.setContentTitle("title");
noBuilder.setContentText(message);
noBuilder.setContentIntent(pendingIntent);
noBuilder.setSound(sound);
NotificationManager notificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(0, noBuilder.build()); //0 = ID of notification
}
}
Lastly, as it may be of some assistance, the information transporter/networking class:
public class Transporter {
private String subject;
private String request;
private String key;
private Date lastUpdateDate;
private boolean forceLoad = false;
private Date requestDate;
private Date responseDate;
private int status;
private String statusMsg = "";
private String tempKey = "";
private JSONObject additionalInfo = null;
private JSONObject parameters;
public static String sessionGUID = "";
public static String userGUID = "";
public static String SERVER = Constants.qa_api;
//transporter object to interact with the server, containing information about the request
//made by the user
public Transporter(String pSubject, String pRequest, String pKey,
JSONObject parms, String userGUID, String sessionGUID)
{
subject = pSubject;
request = pRequest;
key = pKey;
parameters = parms;
setUserGUID(userGUID);
setSessionGUID(sessionGUID);
}
//implements an API call for a given transporter, takes 2 arguments:
//the application context (call getApplicationContext() whenever it's called)
//and a String that represents the field that we are trying to update (if there is one)
//i.e. if we are calling getUserFromSession(), we want the user guid so jsonID = "userGUID"
public void makeAPICall(final Context context, final String jsonID) {
RequestQueue mRequestQueue =
RequestQueueSingleton.getInstance(context).getRequestQueue();
String targetURL = getServerURL() + "/Transporter.aspx";
StringRequest postRequest = new StringRequest(Request.Method.POST, targetURL,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
String parseXML= parseXML(response);
System.out.println("response: " + parseXML);
JSONObject lastResponseContent = null;
try {
lastResponseContent = new JSONObject(parseXML);
} catch (JSONException e) {
e.printStackTrace();
}
try {
if (lastResponseContent != null && !jsonID.equals("")) {
String info = lastResponseContent.getString(jsonID);
if (jsonID.equals("userGUID")) {
userGUID = info;
RequestQueueSingleton.getInstance(context).setUserGUID(userGUID);
}
}
//put other things in here to pull whatever info
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
}) {
#Override
public byte[] getBody() throws AuthFailureError {
String body = getXML(subject,
request, "",
sessionGUID, userGUID, null, parameters);
return body.getBytes();
}
};
postRequest.setTag("POST");
mRequestQueue.add(postRequest);
}

you need to send a post to the url "https://android.googleapis.com/gcm/send":
private void sendGCM() {
StringRequest strReq = new StringRequest(Request.Method.POST,
"https://android.googleapis.com/gcm/send", new Response.Listener<String>() {
#Override
public void onResponse(String response) {
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
NetworkResponse networkResponse = error.networkResponse;
Log.e(TAG, "Volley error: " + error.getMessage() + ", code: " + networkResponse);
Toast.makeText(getApplicationContext(), "Volley error: " + error.getMessage(), Toast.LENGTH_SHORT).show();
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<>();
params.put("data", "message that you send");
params.put("to", "token gcm");
Log.e(TAG, "params: " + params.toString());
return params;
}
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String,String> headers = new HashMap<String, String>();
headers.put("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
headers.put("Authorization", "key="google key");
return headers;
}
};
}

So the Volley calls are non-sequential so the first call (to get a userGUID) didn't return before the second call (to register for notifications), so while the token registration was "successful," there was no corresponding user information so it didn't know how/where to send the push notification. To resolve, I made a special case in the makeAPICall class which created another StringRequest which first basically did the normal getUserFromSession but then recursively called MakeAPICall with the new userGUID information. To avoid an infinite loop, I used an if else statement: (if userGUID == null || userGUID.equals("")) then I did the recursive call, so when the first call returned that conditional was always false and it would only make one recursive call. This answer may be a rambling a bit, but the key take away is using onResponse to make another Volley call for sequential requests. See: Volley - serial requests instead of parallel? and Does Volley library handles all the request sequentially