Android: "No such instance field" using retrofit enqueue

Question

I am trying to make an API call to register users for push notifications.

I have read in other posts that using .execute() instead of .enqueue may work better? But when debugging, it jumped from call.execute() to the catch block.

In my interface file for API calls, jsonPlaceHolderApi:

@FormUrlEncoded
@POST("RegisterPushNotification")
Call<String> registerPushNotification(@Field("accessToken") String accessToken, @Field("deviceToken") String deviceToken, @Field("platform") String platform, @Field("phone_number") String phone_number);

In SettingsActivity, where the sendRegistrationToServer is called:

public void onClick(DialogInterface d, int which) {
     if (which == -1) {
            phoneNumberFromInput = input.getText().toString();
            //actually make the API call to register for push notifications
            MyFirebaseMessagingService firebase = new MyFirebaseMessagingService(accessToken, deviceToken, phoneNumberFromInput);
            firebase.sendRegistrationToServer();
      }
}

In MyFirebaseMessagingService

public void sendRegistrationToServer() {

        Retrofit retrofit = new Retrofit.Builder()
           .baseUrl("https://fakelinktomyapi.com/api/")
           .addConverterFactory(GsonConverterFactory.create())
           .build();
        JsonPlaceHolderApi jsonPlaceHolderApi = retrofit.create(JsonPlaceHolderApi.class);
        Call<String> call = jsonPlaceHolderApi.registerPushNotification(accessToken, deviceToken, "Android", phoneNumber);

        call.enqueue(new Callback<String>() {
            @Override
            public void onResponse(Call<String> call, Response<String> response) {
                if (response.isSuccessful()){
                    String message = "You're all set up to receive push notifications on this device. You may opt out at any time.";
                    Toast toast = Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT);
                    toast.setGravity(Gravity.TOP|Gravity.CENTER_HORIZONTAL, 0, 0);
                    toast.show();
                }
                else {
                    String message = "We're having trouble setting up push notifications for that number. Please try again.";
                    Toast toast = Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT);
                    toast.setGravity(Gravity.TOP|Gravity.CENTER_HORIZONTAL, 0, 0);
                    toast.show();
                }
            }
            @Override
            public void onFailure(Call<String> call, Throwable t) {
                Log.i("failure", "could not register for push");
            }
        });
    }

Even though the phone number, access token, and device token were all NOT null (I printed their values and the debugger showed them too), once I step INTO the line "call.enqueue(new Callback)", the debugger shows this error:

phoneNumber = No such instance field: 'phoneNumber'

jsonPlaceHolderApi = No such instance field: 'jsonPlaceHolderApi'

accessToken = No such instance field: 'accessToken'

deviceToken = no such instance field 'deviceToken'

your `onFailure` should be something like : `Log.e("failure",t.toString() )` or `public void onFailure(Call call, Throwable t) { t.printStackTrace(); }` — a_local_nobody, Sep 06 '19 at 05:01
that's not the solution to your problem, but will actually give useful info if there's anything wrong with the call — a_local_nobody, Sep 06 '19 at 05:02
might just be this https://stackoverflow.com/questions/28646999/no-such-instance-field — a_local_nobody, Sep 06 '19 at 05:16
@a_local_nobody what is that person actually suggesting the solution is? it's not clear — Vanessa, Sep 06 '19 at 20:13
well, the answer said you should maybe just try to restart your android studio, it's potentially just a bug with android studio — a_local_nobody, Sep 10 '19 at 06:38

score 0 · Answer 1 · answered Sep 05 '19 at 21:05

0

I think the problem is happening because you are not using any retrofit object to get access to the interface you wrote.

You can resolve this by adding this two lines at the beginning of your sendRegistrationToServer() function

Retrofit retrofit = RetrofitFactory.getRetrofit();
JsonPlaceHolderApi jsonPlaceHolderApi = retrofit.create(JsonPlaceHolderApi.class);

answered Sep 05 '19 at 21:05

Fahim Al Mahmud Ashik

1,083
10
26

Actually I did use a retrofit object-- I will update my post with that code. – Vanessa Sep 05 '19 at 21:44

Android: "No such instance field" using retrofit enqueue

1 Answers1