Expected BEGIN_ARRAY but was BEGIN_OBJECT in Retrofit

Question

I am new to android programming and can anyone help me or point out why its giving me this error I want to fetch some data from the server such as under the Hardware json and get the names and status, but when i call api its shows me this.

@MuhannadFakhouri I've edited my post kindly check it above. — Yen Bico, Nov 19 '19 at 07:05
Possible duplicate of [Retrofit2 Android: Expected BEGIN\_ARRAY but was BEGIN\_OBJECT at line 1 column 2 path $](https://stackoverflow.com/questions/36177629/retrofit2-android-expected-begin-array-but-was-begin-object-at-line-1-column-2) — Saurabh Thorat, Nov 19 '19 at 07:05
There you go ... your response starts with {, but you're considering it to be an array — Muhannad Fakhouri, Nov 19 '19 at 07:06

Md. Asaduzzaman · Answer 1 · 2019-11-19T07:21:06.193

Your response return an object instead of array.

Instead of

@GET("system_monitor")
Call<List<ObjectList>> getHardware();

use

@GET("system_monitor")
Call<ObjectList> getHardware();

And then use it like below:

Call<ObjectList> call = webRequestAPI.getHardware();

call.enqueue(new Callback<ObjectList>() {
    @Override
    public void onResponse(Call<ObjectList> call, Response<ObjectList> response) {

        if (!response.isSuccessful()) {
            textViewHardwareName.setText("Code: " + response.code());
            return;
        }

        ObjectList system_monitor = response.body();

        ...
    }

    @Override
    public void onFailure(Call<ObjectList> call, Throwable t) {
        textViewHardwareName.setText(t.getMessage());

    }
});

@YenBiko, Here the solution. Check and let me know – Md. Asaduzzaman Nov 19 '19 at 07:11 — Md. Asaduzzaman, Nov 19 '19 at 07:11

score 0 · Answer 2 · answered Nov 19 '19 at 07:09

0

Change the line

public void onResponse(Call<List<ObjectList>> call, Response<List<ObjectList>> response) {

to

public void onResponse(Call<List<ObjectList>> call, Response<ObjectList> response) {

answered Nov 19 '19 at 07:09

Muhannad Fakhouri

1,468
11
14

score 0 · Answer 3 · answered Nov 19 '19 at 07:10

As per your code, you are expecting response as List. But Actual response is object. So, you need to generate model class based on your response and set in code for output.

Your Model should be like :

public class Application {
  ArrayList<Object> hardware = new ArrayList<Object>();
  Header HeaderObject;
  ArrayList<Object> software = new ArrayList<Object>();


 // Getter Methods 

  public Header getHeader() {
    return HeaderObject;
  }

 // Setter Methods 

  public void setHeader( Header headerObject ) {
    this.HeaderObject = headerObject;
  }
}
public class Header {
  Stamp StampObject;
  private String frame_id;
  private float seq;


 // Getter Methods 

  public Stamp getStamp() {
    return StampObject;
  }

  public String getFrame_id() {
    return frame_id;
  }

  public float getSeq() {
    return seq;
  }

 // Setter Methods 

  public void setStamp( Stamp stampObject ) {
    this.StampObject = stampObject;
  }

  public void setFrame_id( String frame_id ) {
    this.frame_id = frame_id;
  }

  public void setSeq( float seq ) {
    this.seq = seq;
  }
}
public class Stamp {
  private float secs;
  private float nsecs;


 // Getter Methods 

  public float getSecs() {
    return secs;
  }

  public float getNsecs() {
    return nsecs;
  }

 // Setter Methods 

  public void setSecs( float secs ) {
    this.secs = secs;
  }

  public void setNsecs( float nsecs ) {
    this.nsecs = nsecs;
  }
}

Then change below line :

public void onResponse(Call<List<ObjectList>> call, Response<Application> response) {

score 0 · Answer 4 · answered Nov 19 '19 at 07:10

0

Change this:

@GET("system_monitor")
Call<List<ObjectList>> getHardware();

to

@GET("system_monitor")
Call<ObjectList> getHardware();

answered Nov 19 '19 at 07:10

faranjit

1,567
1
15
22

Ashish srivastava · Answer 5 · 2019-11-19T07:29:43.460

The best thing for your scenario hardware and Software are as objects , which have two property 1.Name 2. Object status.

So I recommend you to create a class name as System and put there these two variables so finally your class looks like :

Class System 
 {
String object_name;
boolean object_status; 
 }

and your getter setter . And update your model class like this

@SerializedName("hardware")
@Expose
public List<System> hardware;

@SerializedName("software")
@Expose
public List<System> software;

and change your retrofit response holder as.

public void onResponse(Call<List<ObjectList>> call, Response<ObjectList> 
response) {

Expected BEGIN_ARRAY but was BEGIN_OBJECT in Retrofit

5 Answers5