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how to send POST using retrofit, await process and receive response JSON?

In my app, I send a json with information to the server, which is processed and after having a result, it returns another Json response. I don't know how to read that response Json.
this is part of code:
`
private void sendData(String tipo, String dni, String instrucciones, String video) {
progressDialog.setMessage("wait ...");
progressDialog.setCancelable(false);
progressDialog.show();
ApiInterface apiInterface = SendDeviceDetails.getRetrofit().create(ApiInterface.class);
final PostModel postModel= new PostModel(tipo, dni, instrucciones, video);
Call<PostModel> call = apiInterface.PostData(postModel);
call.enqueue(new Callback<PostModel>() {
#Override
public void onResponse(Call<PostModel> call, Response<PostModel> response) {
progressDialog.dismiss();
if (response.isSuccessful()) {
Toast.makeText(MainActivity3.this, response.body().getStatus(), Toast.LENGTH_LONG).show();
}
}
#Override
public void onFailure(Call<PostModel> call, Throwable t) {
progressDialog.dismiss();
Toast.makeText(MainActivity3.this, "error in conexion", Toast.LENGTH_SHORT).show();
}
});
`
It runs fine on submit, process, I can read the result of the service, but I don't know how to read the response json
The server sends me this json:
results JSON :{"status":"1","message":"ok","ID":"609691","NAME":"xxxxxxxxx"}

you declare model class look like this
public class PostModel {
// request
..................
........
// response
#SerializedName("status")
public String status;
#SerializedName("message")
public String message;
#SerializedName("ID")
public String ID;
#SerializedName("NAME")
public String NAME;
}
read response
PostModel postModel = response.body();
String message = postModel.message;
Toast.makeText(context, "message", Toast.LENGTH_SHORT).show();

Let's say you want to send the PostModel model as a request object and receive the PostResultModel object as a response. Then you create the interface with the method:
public interface ApiInterface {
Call<PostResultModel> postData(#Body PostModel request);
}
public class PostResultModel {
#SerializedName("status")
private String status;
#SerializedName("message")
private String message;
#SerializedName("ID")
private String id;
#SerializedName("NAME")
private String name;
// getters and setters
}
You can use this method like this:
ApiInterface apiInterface = SendDeviceDetails.getRetrofit().create(ApiInterface.class);
final PostModel postModel= new PostModel(tipo, dni, instrucciones, video);
Call<PostResultModel> call = apiInterface.postData(postModel);
call.enqueue(
new Callback<PostResultModel>() {
#Override
public void onResponse(Call<PostResultModel> call, Response<PostResultModel> response) {
if (response.isSuccessful()) {
final PostResultModel postResultModel = response.body();
// todo some logic with reponse
}
}
#Override
public void onFailure(Call<PostResultModel> call, Throwable t) {
// todo some logic when request failed
}
}
);
See this article to get more information

How to get only certain fields from JSON with retrofit

I have a problem with Retrofit. I am working on an Android app which needs to get information about a product from Open Food Facts API. I tried with Retrofit, I created a class with the information I want from JSON (I only need a few fields and I didn't want to make a class with all the JSON fields, because there are over 50 I think)
public class Product {
#SerializedName("product_name_en")
private String name;
#SerializedName("brands")
private String company;
#SerializedName("update_key")
private int key;
public String getName() {
return name;
}
public String getCompany() {
return company;
}
public int getKey() {
return key;
}
}
Then I created an interface with the #GET method and the relative URL to the API endpoint
public interface OpenFoodFactsAPI {
#Headers("User-Agent: Fooducate - Android - Version 1.0")
#GET("/api/v0/product/01223004")
Call<Product> getProducts();
}
And inside my fragment I did this
TextView text = view.findViewById(R.id.txt);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://us.openfoodfacts.org")
.addConverterFactory(GsonConverterFactory.create())
.build();
OpenFoodFactsAPI jsonPlaceHolderApi = retrofit.create(OpenFoodFactsAPI.class);
Call<Product> call = jsonPlaceHolderApi.getProducts();
call.enqueue(new Callback<Product>() {
#Override
public void onResponse(Call<Product> call, Response<Product> response) {
if (!response.isSuccessful()) {
text.setText("Code: " + response.code());
return;
}
Product product = response.body();
String content = "";
content += "NAME: " + product.getName() + "\n";
content += "COMPANY: " + product.getCompany() + "\n";
content += "KEY: " + product.getKey() + "\n";
text.append(content);
}
#Override
public void onFailure(Call<Product> call, Throwable t) {
text.setText(t.getMessage());
}
});
I tried the get request on a website and it works. However, in my app an empty response is returned.
You can view the JSON from the api here
If you have any idea about this problem, please answer. Thank you!

From the API you are not getting exactly the Product as response. You are getting another object which is Product is a child object.
You need to create a response Like below,
public class ResponseObject{
#SerializedName("status")
private int status;
#SerializedName("status_verbose")
private String status_verbose;
#SerializedName("product")
private Product product;
//getters and setters goes here
}
then your interface should be like below as you are expecting ResponseObject here.
public interface OpenFoodFactsAPI {
#Headers("User-Agent: Fooducate - Android - Version 1.0")
#GET("/api/v0/product/01223004")
Call<ResponseObject> getProducts();
}
This will solve your problem. Update me If you have any problem with this.

After using
public class ResponseObject{
#SerializedName("status")
private int status;
#SerializedName("status_verbose")
private String status_verbose;
#SerializedName("product")
private Product product;
}
Just change
public int getKey() {return key;}
to
public String getKey() {
return key;
}
Otherwise
Error: java.lang.NumberFormatException: For input string: "ecoscore20210127"
because in json it exists like "update_key": "ecoscore20210127"

Method always return empty list

I am using mvp Design pattern in android development and i am using retrofit2 with it ... when i run the function to get me information from a the web it get the information but returns null list
the Response.Body come with response that mean that the code works
the model function
List<SearchDdb> searchResult;
private Context context;
public MainModel(Context context){this.context=context;}
public List<SearchDdb> searchUser(String name) {
final MainPresenter presenter = new MainPresenter(context);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://jsonplaceholder.typicode.com/")
.addConverterFactory(GsonConverterFactory.create())
.build();
Db db = retrofit.create(Db.class);
Call<List<SearchDdb>> call = db.getUsers(name);
call.enqueue(new Callback<List<SearchDdb>>() {
#Override
public void onResponse(Call<List<SearchDdb>> call, Response<List<SearchDdb>> response) {
if(!response.isSuccessful()){
presenter.showDialog();
}
searchResult = response.body();
}
#Override
public void onFailure(Call<List<SearchDdb>> call, Throwable t) {
}
});
return searchResult;
}
the SearchDdb file
private int id;
private String name;
private String grade;
private String age;
private String address;
public int getId() {
return id;
}
public String getName() {
return name;
}
public String getGrade() {
return grade;
}
public String getAge() {
return age;
}
public String getAddress() {
return address;
}
}
How i call the function
List<SearchDdb> ressult = presenter.searchUser("1");

You cant call it like List<SearchDdb> ressult = presenter.searchUser("1"); because searchUser method makes an async request via retrofit. This way searchUse returns null searchResult because response has not come yet.
Define a LiveData in your viewmodel class and observe it in your activity/fragment. When response comes from api in
onResponse in searchUser post that response to live data and use it where you observe.
If you want to see a tutorial you can look at this article.
Here is another example.

Retrofit parse Json with array of parameter

I have a problem when parsing json by using Retrofit can't get any of data , This URL request array of parameter
https://lao.busnavi.asia/api/location.php?ids%5B%5D=132&ids%5B%5D=133&ids%5B%5D=131
JSON from server that looks like this
json data
My code
LatestBusLocation.java
#SerializedName("id") private int id;
#SerializedName("status") private int status;
#SerializedName("route_id") private String routeId;
#SerializedName("lng") private double lng;
#SerializedName("lat") private double lat;
#SerializedName("accuracy") private double accuracy;
#SerializedName("speed") private double speed;
#SerializedName("heading") private float heading;
#SerializedName("date") private Date date;
Interface class
public interface ApiService {
#POST("location.php")
Call<LatestBusLocation> loadLatestBusLocation(#Query("ids[]") int[] ids);
}
MainActivity.java
int[] ids = {131, 132, 133};
Call<LatestBusLocation> call = HttpManager.getInstance()
.getService().loadLatestBusLocation(ids);
call.enqueue(new Callback<LatestBusLocation>() {
#Override
public void onResponse(Call<LatestBusLocation> call, Response<LatestBusLocation> response) {
Log.e("WorkOrNote1", "Working");
if (response.isSuccessful()) {
dao = response.body();
Log.d("daoResponse", String.valueOf(dao.getId()));
} else {
try {
Log.e("LatestBusLocation", response.errorBody().string());
} catch (IOException e) {
e.printStackTrace();
}
}
}
#Override
public void onFailure(Call<LatestBusLocation> call, Throwable t) {
Log.e("onFailure", t.toString());
}
});

Retrofit fails to map your object because you have specified an LatestBusLocation in the Call. This should be a List<LatestBusLocation>.
Aditionally, you will have to add a deserializer to map correctlly because you are getting an object (with ids keys) instead of a proper array. Look at this relationed answer

Retrofit Android Application GET JSON from Node.js Server

I solved the problem.
I was sending plain-text in the server.
Changed the line to read:
response.writeHead(200, {'Content-Type': 'application/json'});
Quick question. My friend recommended looking into Retrofit rather than using my ASync task for my REST android application. I am having one small problem since I am new to the system. The server runs using Node.js to send JSON objects by means of .stringify() and so when I retrieve an object it is a String rather than a JSON, and I cannot convert it to my List of the appropriate objects. I am guessing the error is due to a cast exception because it is sending a string because I get the exception:
com.google.gson.JsonSyntaxException
Any help would be great. Here is the code I thought would be appropriate.
Android Client Code Example below:
private void requestData() {
RestAdapter adapter = new RestAdapter.Builder().setEndpoint(ENDPOINT).build();
UnitAPI unit_api = adapter.create(UnitAPI.class);
unit_api.getUnits(new Callback<List<Unit>>() {
#Override
public void success(List<Unit> t, Response response) {
units = t;
updateDisplay();
}
#Override
public void failure(RetrofitError error) {
Log.d("Failure UnitGet()", error.getMessage());
}
});
}
Android Unit.class:
public class Unit {
private String ID;
private long bearing;
private long lat;
private long lng;
private String type;
public String getID() {
return ID;
}
public void setID(String ID){
this.ID = ID;
}
public long getBearing() {
return bearing;
}
public void setBearing(long bearing){
this.bearing = bearing;
}
public void setLat(long lat){
this.lat = lat;
}
public long getLat(){
return lat;
}
public void setLng(long lng){
this.lng = lng;
}
public long getLng(){
return lng;
}
public void setType(String type){
this.type = type;
}
public String getType(){
return type;
}
}
The server sends the .json file via the command:
if (method == "GET") {
response.write(JSON.stringify(unitsJSON));
}
Any thoughts on how I can convert it to a list of units from the string on the client side or a json object on the server side?
Thanks!

I solved the problem. I was sending plain-text in the server. Changed the line to read:
response.writeHead(200, {'Content-Type': 'application/json'});

I think you must add json-parser to package using npm
then
in response write
res.end(JSON.stringfy('your resp0onse here'));