saveemailinshared.java

// make listEmails global and also initialise this in onCreate so you get already saved emails when you come to this screen
ArrayList<String> listEmails;

public void getDataForId() {

    SharedPreferences authToken = getSharedPreferences("authToken", Context.MODE_PRIVATE);
    String token = authToken.getString("token", "");

    apiInterface = ApiClient.getApiClient().create(ApiInterface.class);
    Call<UserResponse> call = apiInterface.getData("Bearer " + token);
    call.enqueue(new Callback<UserResponse>() {
        @Override
        public void onResponse(Call<UserResponse> call, Response<UserResponse> response) {

            if (response.isSuccessful()) {

                String emp_email = response.body().getUser().getEmail();

                listEmails = getFromPrefs(this);

                if(listEmails == null){
                   listEmails = new ArrayList<>();
                   listEmails.add(emp_email);
                }else{
                  if(!listEmails.contains(emp_email)){
                     listEmails.add(emp_email);
                  }
                }
                

                saveToPrefs(this, listEmails);

                /*Log.i("MainActivity", "onCreate: " + getFromPrefs(this).toString());

                if(!listEmails.contains(emp_email)){
                   listEmails.add("b@b.b");
                }

                saveToPrefs(this, listEmails);

                Log.i("MainActivity", "onCreate: " + getFromPrefs(this).toString());*/


            } else {
            }
        }

        @Override
        public void onFailure(Call<UserResponse> call, Throwable t) {
        }
    });
}