VolleyAPI

package com.example.android.jsonurl;

       
        import android.os.Bundle;
        import android.support.v7.app.AppCompatActivity;
        import android.widget.TextView;

        import com.android.volley.Request;
        import com.android.volley.RequestQueue;
        import com.android.volley.Response;
        import com.android.volley.VolleyError;
        import com.android.volley.toolbox.JsonObjectRequest;
        import com.android.volley.toolbox.Volley;
        import org.json.JSONException;
        import org.json.JSONObject;

public class MainActivity extends AppCompatActivity {

    private TextView type, code, fbid;
    String jsonUrl = "https://graph.facebook.com/me";
    RequestQueue requestQueue;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        // Creates the Volley request queue
        requestQueue = Volley.newRequestQueue(this);

        // Casts results into the TextView found within the main layout XML
        type = (TextView) findViewById(R.id.type);
        code = (TextView) findViewById(R.id.code);
        fbid = (TextView) findViewById(R.id.fbid);

        JsonObjectRequest jsObjRequest = new JsonObjectRequest
                (Request.Method.GET, jsonUrl, null, new Response.Listener<JSONObject>() {

                    @Override
                    public void onResponse(JSONObject response) {
                        try {
                            JSONObject jsonObj = response.getJSONObject("error");
                            String typeS = jsonObj.getString("type");
                            String codeS = jsonObj.getString("code");
                            String fbtrace_id = jsonObj.getString("fbtrace_id");
                            type.setText(typeS);
                            code.setText(codeS);
                            fbid.setText(fbtrace_id);
                        }
                        // Try and catch are included to handle any errors due to JSON
                        catch (JSONException e) {
                            // If an error occurs, this prints the error to the log
                            e.printStackTrace();
                            type.setText("error");
                        }
                    }
                }, new Response.ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                        // TODO Auto-generated method stub

                    }
                });

        requestQueue.add(jsObjRequest);
    }
}