Lazy loading Images from JSON not downloaded in SD Card

问题

I am writing a program in which want to download images from online url and want to show in Staggered GridView format, i found Staggered GridView code from here

and using this link to download images from online link in JSON format

But the issue is, i am not able to download images into SD Card using below code.....

MainActivity.java:-

   public class MainActivity extends Activity {

    private String urls[];
    String location = "http://snapoodle.com/APIS/android/feed.php";
    static final String TAG_ITEMS = "print";
    StaggeredGridView gridView;


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

        gridView = (StaggeredGridView) this.findViewById(R.id.staggeredGridView1);

        getImages get= (getImages) new getImages();
        get.execute(location);

        // new getImages().execute();

    }

     class getImages extends AsyncTask<String, Void, String> {

            @Override
            protected String doInBackground(String... params) {
                // TODO Auto-generated method stub

                JSONObject json = JSONfunctions
                        .getJSONfromURL(location);

                try {
                    JSONArray jarray;
                    jarray = json.getJSONArray(TAG_ITEMS);
                    urls = new String[jarray.length()];

                    for (int i = 0; i < jarray.length(); i++) {
                        JSONObject gridImages = jarray.getJSONObject(i);
                        urls[i] = gridImages.getString("saved_location");                       
                    }

                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                return null;
            }

        }

     protected void onPostExecute(Void args) {
         StaggeredAdapter adapter = new StaggeredAdapter(MainActivity.this,
                    R.id.imageView1, urls);

            gridView.setAdapter(adapter);
            adapter.notifyDataSetChanged();
     }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

JSONfunctions.java:

public class JSONfunctions {

     public static JSONObject getJSONfromURL(String url) {
            InputStream is = null;
            String result = "";
            JSONObject jArray = null;

            // Download JSON data from URL
            try {
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost(url);
                HttpResponse response = httpclient.execute(httppost);
                HttpEntity entity = response.getEntity();
                is = entity.getContent();

            } catch (Exception e) {
                Log.e("log_tag", "Error in http connection " + e.toString());
            }

            // Convert response to string
            try {
                BufferedReader reader = new BufferedReader(new InputStreamReader(
                        is, "iso-8859-1"), 8);
                StringBuilder sb = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null) {
                    sb.append(line + "\n");
                }
                is.close();
                result = sb.toString();
            } catch (Exception e) {
                Log.e("log_tag", "Error converting result " + e.toString());
            }

            try {

                jArray = new JSONObject(result);
            } catch (JSONException e) {
                Log.e("log_tag", "Error parsing data " + e.toString());
            }

            return jArray;
        }

}