Android Volley请求Gson

Question

Looking to use the class on the android developers website that uses Volley and Gson to fetch and deserialize json data from a url to parse into an array. I'm still a beginner so I was trying to instantiate the class but I'm not sure how to format the parameters. Tried looking for implementation but they seem to use other API's in addition. The returned json only has one field and value so class object clazz has one field.

public class GsonRequest<T> extends Request<T> {
private final Gson gson = new Gson();
private final Class<T> clazz;
private final Map<String, String> headers;
private final Listener<T> listener;

/**
 * Make a GET request and return a parsed object from JSON.
 *
 * @param url URL of the request to make
 * @param clazz Relevant class object, for Gson's reflection
 * @param headers Map of request headers
 */
public GsonRequest(String url, Class<T> clazz, Map<String, String> headers,
        Listener<T> listener, ErrorListener errorListener) {
    super(Method.GET, url, errorListener);
    this.clazz = clazz;
    this.headers = headers;
    this.listener = listener;
}

@Override
public Map<String, String> getHeaders() throws AuthFailureError {
    return headers != null ? headers : super.getHeaders();
}

@Override
protected void deliverResponse(T response) {
    listener.onResponse(response);
}

@Override
protected Response<T> parseNetworkResponse(NetworkResponse response) {
    try {
        String json = new String(
                response.data,
                HttpHeaderParser.parseCharset(response.headers));
        return Response.success(
                gson.fromJson(json, clazz),
                HttpHeaderParser.parseCacheHeaders(response));
    } catch (UnsupportedEncodingException e) {
        return Response.error(new ParseError(e));
    } catch (JsonSyntaxException e) {
        return Response.error(new ParseError(e));
    }
}
}

Just looking to get the example up and running So it at least can receive the data to display on screen.

Answer 1

First, you need to define a model class based on your expected JSON response.

For example, If your JSON is Array of Users, then model class will look like this,

Users.Java

public class Users extends Object implements Serializable {
    private static final long serialVersionUID = 1L;
    @SerializedName("users")
    private ArrayList<User> arrListUser;

    public ArrayList<User> getArrListBusinessObj() {
        return arrListUser;
    }

    public static class User extends Object implements Serializable  
    {
        private static final long serialVersionUID = 1L;

        private String user_id;
        private String name;
        private String artwork;

        public String getBusinessObjId() {
            return user_id;
        }

        public String getName() {
            return name;
        }

        public String getArtwork() {
            return artwork;
        }

    }
}

Then where you are receiving your network response, call below method :

Users users = (Users)gson.fromJson(data, Users.class); //data is string form response from server