GsonRequest.java

/** Volley request parsing JSON strings using the gson deserializer */
public class GsonRequest<T> extends Request<T> {
  /** Type of Generic. */
  private final Class<T> mTypeOfT;
  /** Response listener */
  private final Response.Listener<T> mListener;
  /** GSON parser */
  private final Gson mGson;

  /**
   * Create a new GSON JSON-parser request.
   *
   * @param typeOfT       Type of generic.
   * @param url           Request url.
   * @param listener      Response listener.
   * @param errorListener Error listener.
   */
  public GsonRequest(final Class<T> typeOfT, final String url, final Response.Listener<T> listener,
                     final Response.ErrorListener errorListener) {
    this(typeOfT, url, listener, errorListener, new Gson());
  }

  /**
   * Create a new GSON JSON-parser request with a custom gson instance (useful for specifying
   * custom date formats, etc.)
   *
   * @param typeOfT       Type of generic.
   * @param url           Request url.
   * @param listener      Response listener.
   * @param errorListener Error listener.
   * @param gson          Custom GSON instance.
   */
  public GsonRequest(final Class<T> typeOfT, final String url, final Response.Listener<T> listener,
                     final Response.ErrorListener errorListener, final Gson gson) {
    super(Method.GET, url, errorListener);
    mListener = listener;
    mTypeOfT = typeOfT;
    mGson = gson;
  }

  @Override
  protected Response<T> parseNetworkResponse(final NetworkResponse response) {
    try {
      final String jsonString = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
      return Response.success(mGson.fromJson(jsonString, mTypeOfT),
        HttpHeaderParser.parseCacheHeaders(response));
    } catch (Exception e) {
      return Response.error(new ParseError(e));
    }
  }

  @Override
  protected void deliverResponse(final T response) {
    if (!isCanceled() && (mListener != null)) {
      mListener.onResponse(response);
    }
  }
}