GSON throwing "Expected BEGIN_OBJECT but was BEGIN_ARRAY"?
Alternative could be
to make your response look like
myCustom_JSONResponse
{"master":[
{
"updated_at":"2012-03-02 21:06:01",
"fetched_at":"2012-03-02 21:28:37.728840",
"description":null,
"language":null,
"title":"JOHN",
"url":"http://rus.JOHN.JOHN/rss.php",
"icon_url":null,
"logo_url":null,
"id":"4f4791da203d0c2d76000035",
"modified":"2012-03-02 23:28:58.840076"
},
{
"updated_at":"2012-03-02 14:07:44",
"fetched_at":"2012-03-02 21:28:37.033108",
"description":null,
"language":null,
"title":"PETER",
"url":"http://PETER.PETER.lv/rss.php",
"icon_url":null,
"logo_url":null,
"id":"4f476f61203d0c2d89000253",
"modified":"2012-03-02 23:28:57.928001"
}
]
}
instead of
server_JSONResponse
[
{
"updated_at":"2012-03-02 21:06:01",
"fetched_at":"2012-03-02 21:28:37.728840",
"description":null,
"language":null,
"title":"JOHN",
"url":"http://rus.JOHN.JOHN/rss.php",
"icon_url":null,
"logo_url":null,
"id":"4f4791da203d0c2d76000035",
"modified":"2012-03-02 23:28:58.840076"
},
{
"updated_at":"2012-03-02 14:07:44",
"fetched_at":"2012-03-02 21:28:37.033108",
"description":null,
"language":null,
"title":"PETER",
"url":"http://PETER.PETER.lv/rss.php",
"icon_url":null,
"logo_url":null,
"id":"4f476f61203d0c2d89000253",
"modified":"2012-03-02 23:28:57.928001"
}
]
CODE
String server_JSONResponse =.... // the string in which you are getting your JSON Response after hitting URL
String myCustom_JSONResponse="";// in which we will keep our response after adding object element to it
MyClass apiResponse = new MyClass();
myCustom_JSONResponse="{\"master\":"+server_JSONResponse+"}";
apiResponse = gson.fromJson(myCustom_JSONResponse, MyClass .class);
After this it will be just any other GSON Parsing
The problem is that you are asking for an object of type ChannelSearchEnum but what you actually have is an object of type List<ChannelSearchEnum>.
You can achieve this with:
Type collectionType = new TypeToken<List<ChannelSearchEnum>>(){}.getType();
List<ChannelSearchEnum> lcs = (List<ChannelSearchEnum>) new Gson()
.fromJson( jstring , collectionType);
In my case JSON string:
[{"category":"College Affordability",
"uid":"150151",
"body":"Ended more than $60 billion in wasteful subsidies for big banks and used the savings to put the cost of college within reach for more families.",
"url":"http:\/\/www.whitehouse.gov\/economy\/middle-class\/helping middle-class-families-pay-for-college",
"url_title":"ending subsidies for student loan lenders",
"type":"Progress",
"path":"node\/150385"}]
and I print "category" and "url_title" in recycleview
Datum.class
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;
public class Datum {
@SerializedName("category")
@Expose
private String category;
@SerializedName("uid")
@Expose
private String uid;
@SerializedName("url_title")
@Expose
private String urlTitle;
/**
* @return The category
*/
public String getCategory() {
return category;
}
/**
* @param category The category
*/
public void setCategory(String category) {
this.category = category;
}
/**
* @return The uid
*/
public String getUid() {
return uid;
}
/**
* @param uid The uid
*/
public void setUid(String uid) {
this.uid = uid;
}
/**
* @return The urlTitle
*/
public String getUrlTitle() {
return urlTitle;
}
/**
* @param urlTitle The url_title
*/
public void setUrlTitle(String urlTitle) {
this.urlTitle = urlTitle;
}
}
RequestInterface
import java.util.List;
import retrofit2.Call;
import retrofit2.http.GET;
/**
* Created by Shweta.Chauhan on 13/07/16.
*/
public interface RequestInterface {
@GET("facts/json/progress/all")
Call<List<Datum>> getJSON();
}
DataAdapter
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Shweta.Chauhan on 13/07/16.
*/
public class DataAdapter extends RecyclerView.Adapter<DataAdapter.MyViewHolder>{
private Context context;
private List<Datum> dataList;
public DataAdapter(Context context, List<Datum> dataList) {
this.context = context;
this.dataList = dataList;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.data,parent,false);
return new MyViewHolder(view);
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.categoryTV.setText(dataList.get(position).getCategory());
holder.urltitleTV.setText(dataList.get(position).getUrlTitle());
}
@Override
public int getItemCount() {
return dataList.size();
}
public class MyViewHolder extends RecyclerView.ViewHolder{
public TextView categoryTV, urltitleTV;
public MyViewHolder(View itemView) {
super(itemView);
categoryTV = (TextView) itemView.findViewById(R.id.txt_category);
urltitleTV = (TextView) itemView.findViewById(R.id.txt_urltitle);
}
}
}
and finally MainActivity.java
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private DataAdapter dataAdapter;
private List<Datum> dataArrayList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initViews();
}
private void initViews(){
recyclerView=(RecyclerView) findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
loadJSON();
}
private void loadJSON(){
dataArrayList = new ArrayList<>();
Retrofit retrofit=new Retrofit.Builder().baseUrl("https://www.whitehouse.gov/").addConverterFactory(GsonConverterFactory.create()).build();
RequestInterface requestInterface=retrofit.create(RequestInterface.class);
Call<List<Datum>> call= requestInterface.getJSON();
call.enqueue(new Callback<List<Datum>>() {
@Override
public void onResponse(Call<List<Datum>> call, Response<List<Datum>> response) {
dataArrayList = response.body();
dataAdapter=new DataAdapter(getApplicationContext(),dataArrayList);
recyclerView.setAdapter(dataAdapter);
}
@Override
public void onFailure(Call<List<Datum>> call, Throwable t) {
Log.e("Error",t.getMessage());
}
});
}
}
The problem is you're telling Gson you have an object of your type. You don't. You have an array of objects of your type. You can't just try and cast the result like that and expect it to magically work ;)
The User guide for Gson Explains how to deal with this:
https://github.com/google/gson/blob/master/UserGuide.md
This will work:
ChannelSearchEnum[] enums = gson.fromJson(yourJson, ChannelSearchEnum[].class);
But this is better:
Type collectionType = new TypeToken<Collection<ChannelSearchEnum>>(){}.getType();
Collection<ChannelSearchEnum> enums = gson.fromJson(yourJson, collectionType);