I want to get the retrofit response list and use it outside the OnResponse function, but went I try to do it I'm always getting a null object.
Here is my source code
ApiInterface apiService = ApiClient.getClient().create(ApiInterface.class);
Call<ActivitiesResponse> call = apiService.getUserActivities(id);
call.enqueue(new Callback<ActivitiesResponse>() {
// If success
#Override
public void onResponse(Call<ActivitiesResponse>call, Response<ActivitiesResponse> response) {
list = response.body().getActivities();// I'm getting a not null response
}
// If failed
#Override
public void onFailure(Call<ActivitiesResponse>call, Throwable t) {
// Log error here since request failed
Log.e(TAG, t.toString());
}
});
//When I try to use the list here I'm getting a null object
Requests are async, so when you try to return a value, the request is likely not done yet so you cannot use it outside of the request. If you want to return values from the request use callback interfaces.
Change your code to a method and pass a callback parameter
Example
public void doRequest(final ApiCallback callback) {
ApiInterface apiService = ApiClient.getClient().create(ApiInterface.class);
Call<ActivitiesResponse> call = apiService.getUserActivities(id);
call.enqueue(new Callback<ActivitiesResponse>() {
// If success
#Override
public void onResponse(Call<ActivitiesResponse>call, Response<ActivitiesResponse> response) {
list = response.body().getActivities();
callback.onSuccess(list); // pass the list
}
// If failed
#Override
public void onFailure(Call<ActivitiesResponse>call, Throwable t) {
// Log error here since request failed
Log.e(TAG, t.toString());
}
});
}
public interface ApiCallback{
void onSuccess(ArrayList<YOURTYPE> result);
}
Example usage in onResume(), basically you can do this anywhere you want:
public void onResume(){
super.onResume();
doRequest(new ApiCallback(){
#Override
public void onSuccess(ArrayList<YOURTYPE> result){
//do stuff here with the list from the request
}
});
}
Let me know if this fits your needs
Because onResponse() runs asynchronously. You can not get its value like that.
You should call the method which uses list value inside onResponse().
For example.
call.enqueue(new Callback<ActivitiesResponse>() {
// If success
#Override
public void onResponse(Call<ActivitiesResponse>call, Response<ActivitiesResponse> response) {
list = response.body().getActivities();// I'm getting a not null response
yourMethod();
}
// If failed
#Override
public void onFailure(Call<ActivitiesResponse>call, Throwable t) {
// Log error here since request failed
Log.e(TAG, t.toString());
}
});
private void yourMethod() {
// list is used somewhere here
}
Related
I am working with retrofit to get some statistics. They arrive at the app. When I try to set some TextView's text to the values they throw a NullPointerException. Is there something I should know?
public void init() {
getStatistics();
txtNrCompleted.setText(String.format("%s", statistics.getTask()));
}
private void getStatistics(){
endpoints = RetrofitJsonCaller.call(APIEndpoints.class);
callStatistics = endpoints.getStatistics(URLEndpoints.getStatistics());
callStatistics.enqueue(new Callback<STATISTIC>() {
#Override
public void onResponse(Call<STATISTIC> call, Response<STATISTIC> response) {
if(response.isSuccessful()) {
setStatistics(response.body());
}else{
Log.d("STATISTICS", "Error: " + response.code());
}
}
#Override
public void onFailure(Call<STATISTIC> call, Throwable t) {
Timber.d(t.getMessage());
}
});
}
public void setStatistics(STATISTIC statistics){
this.statistics = statistics;
}
LOGS:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Integer com.example.taskmanagement.model.STATISTIC.getTaskComplet()' on a null object reference
at com.example.taskmanagement.MainActivity.onCreate(MainActivity.java:111)
at android.app.Activity.performCreate(Activity.java:6948)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1126)
Retrofit is making the call to get the statistics asynchronously, but you are setting the text in the TextView synchronously. You call getStatistics() which triggers the call to get the new statistics but doesn't wait for it to finish. You then set the text immediately after, at which point the statistics object is still null. You need to update the TextView after you get a successful response. For example:
public void init() {
getStatistics();
}
private void getStatistics() {
...
#Override
public void onResponse(Call<STATISTIC> call, Response<STATISTIC> response) {
if (response.isSuccessful()) {
setStatistics(response.body());
// Call the code to update your UI here, as we have now received the stats
updateUI();
} else {
...
}
}
...
}
...
private void updateUI() {
textNrCompleted.setText(String.format("%s", statistics.getTask()));
}
I am having problem while calling two different APIs. There is no problem while calling first API using retrofit but when it reaches second retrofit call, there occurs error. Following is my code.
//for first retrofit call:
apiInterface = ApiClient.getApiClient().create(LekhaDrillInterface.class);
Call<LekhaDrillModel> call = apiInterface.getData(id, memberId);
call.enqueue(new Callback<LekhaDrillModel>() {
#Override
public void onResponse(Call<LekhaDrillModel> call, Response<LekhaDrillModel> response) {
posts = Collections.singletonList(response.body());
adapter = new LekhaBolpatraDrillAdapter(posts, getApplicationContext());
rvLekhaDrill.setAdapter(adapter);
progressBar.setVisibility(View.GONE);
}
#Override
public void onFailure(Call<LekhaDrillModel> call, Throwable t) {
Log.e("error", t.getMessage());
}
});
here is no error and data is set in adapter
//2nd retrofit call
private void callRetrofitListData(){
pariyojanaInterfaces = ApiClient.getApiClient().create(PariyojanaInterface.class);
Log.e("memberIDIDID", String.valueOf(memberId));
Call <Data> call1 = pariyojanaInterfaces.getData(memberId);
call1.enqueue(new Callback<Data>() {
#Override
public void onResponse(Call<Data> call, Response<Data> response) {
datas = (List<Data>) response.body();
if (response.body()!=null){
Log.d("jchhec","chekc");
}
itemListAdapter = new ItemListAdapter(getApplicationContext(), datas);
rv.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
rv.setAdapter(itemListAdapter);
}
#Override
public void onFailure(Call<Data> call1, Throwable t) {
Log.e("error", t.getMessage());
}
});
}
the error is in the line
Call <Data> call1 = pariyojanaInterfaces.getData(memberId);
and the error is
Unable to create call adapter for interface retrofit2.Call for method PariyojanaInterface.getData
PariyojanaInterface.java
public interface PariyojanaInterface { #POST("projectBudget/pariyojanaListForMobile") Call getData(#Query("memberId") int memberId);
Can anybody please help me fix this problem?
First you must change PariyojanaInterface.java to
public interface PariyojanaInterface {
#POST("projectBudget/pariyojanaListForMobile") Call<List<Data>> getData(#Query("memberId") int memberId);
}
I Dont khow what your Data is, so you must replace List<Data> with List<yourData>
And you must change new Callback<Data> To new Callback<List<Data>
I'm using Retrofit 2.0. To get some data from RESTFull services I use procedures like this:
public Call downloadUser() {
// Create RetrofitService
Call<User> call = service.getUser();
call.enqueue(new Callback<User>() {
#Override
public void onResponse(Response<User> response, Retrofit retrofit) {
// Do some operations with User obj if response.isSuccess()
}
#Override
public void onFailure(Throwable t) {
// Failure
}
});
return call;
}
In some cases, I need to cancel my request. I use call.cancel(), but even if I call this procedure Callback.onResponse(...) or Callback.onFailure(...) triggered anyway, so using Call.cancel() doesn't cancel my request and it keeps on going until failure or response.
To know if a call was canceled or if it was truly successful you'll need to two a few things.
First it looks like the version of Retrofit2 you are using needs to be updated
Second you can check if a call was canceled based on the code below. Note that this will deal with cancels from the Call<> or the Dispatcher.class in OKHttp3
#Override
public void onResponse(Response<User> response, Response response) {
if(response != null && response.isSuccessful()) {
//Do Stuff with the response
}
}
#Override
public void onFailure(Call<User> user, Throwable t) {
if(user.isCanceled() || "Canceled".equals(t.getMessage())) {
//Call was canceled
} else {
//Call failed
}
}
I need make POST request with parameters "guid=1" in Body. i use Retrofit2
I try :
#POST("/api/1/model")
Call<ApiModelJson> getPostClub(#Body User body);
User Class:
public class User {
#SerializedName("guid")
String guid;
public User(String guid ) {
this.guid = guid;
}
MailActivity:
User user =new User ("1");
Call<ApiModelJson> call = service.getPostClub(user);
call.enqueue(new Callback<ApiModelJson>() {
#Override
public void onResponse(Response<ApiModelJson> response) {
}
#Override
public void onFailure(Throwable t) {
dialog.dismiss();
}
How make this request?
you have to call call.enqueue, providing an instance of Callback< ApiModelJson>, where you will get the response. enqueue executes your backend call asynchronously. You can read more about call.enqueue here
With code below, you can make the request synchronously:
ApiModelJson responseBody = call.execute();
If you want it to be asynchronous:
call.enqueue(new Callback<ApiModelJson>() {
#Override
public void onResponse(Response<ApiModelJson> response, Retrofit retrofit) {
}
#Override
public void onFailure(Throwable t) {
}
});
I want to implement a error handling mechanism using Retorfit 2.
The solutions that are available are using RetrofitError class which I can't find in the current repo.
If you are making synchronous request, you define your request method in the interface as Call<List<Car>>.
Once you execute the request you receive response and deserialized data wrapped in Response<T> as Response<List<Car>>. This wrapped gives you access to headers, http codes and raw response body.
You can access error body as:
Call<List<Car>> carsCall = carInterface.loadCars();
try {
Response<List<Car>> carsResponse = carsCall.execute();
} catch (IOException e) {
e.printStackTrace();
//network Exception is throw here
}
if(carsResponse != null && !carsResponse.isSuccess() && carsReponse.errorBody() != null){
// handle carsResponse.errorBody()
}
For async calls, you receive Throwable, if I/O exception is thrown during the network call:
Call<List<Car>> call = service.loadCars();
call.enqueue(new Callback<List<Car>>() {
#Override
public void onResponse(Response<List<Car>> response) {
// Get result from response.body(), headers, status codes, etc
}
#Override
public void onFailure(Throwable t) {
//handle error
}
});
Call<List<data>> call = MyService.loadData();
call.enqueue(new Callback<List<data>>() {
#Override
public void onResponse(Call<List<data>> call, Response<List<data>> response) {
if (response.isSuccessful()) {
//Response success. Handle data here
}
else{
//For getting error message
Log.d("Error message",response.message());
//For getting error code. Code is integer value like 200,404 etc
Log.d("Error code",String.valueOf(response.code()));
}
}
#Override
public void onFailure(Call<List<data>> call, Throwable t) {
if (t instanceof IOException){
//Add your code for displaying no network connection error
}
});
The simple method:
int code = response.raw().code();
String message = response.raw().message();