Images are showing when it's scrolling from top to bottom but removing when I am scrolling it bottom to top in gridview?

Question

My images values are showing in logcat but not on screen, I am struggling from2 days what I do?

public class MyFragment extends Fragment {
int mCurrentPage;
Context c;
GridView mListView;
String id, cat;
String strUrl;
TextView tvtitle;
TextView tv_id, tv_rating, tv_url;

private ImageLoader imageLoader;
private DisplayImageOptions options;
private ProgressDialog progressDialog;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Bundle data = getArguments();
    mCurrentPage = data.getInt("current_page", 0);
    imageLoader=ImageLoader.getInstance();

    options = new DisplayImageOptions.Builder()
    .showImageOnLoading(R.drawable.empty_photo)
    .showImageForEmptyUri(R.drawable.empty_photo)
    .showImageOnFail(R.drawable.empty_photo)
    .cacheInMemory(true)
    .cacheOnDisc(true)
    .displayer(new RoundedBitmapDisplayer(20))
    .build();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View v = null;
    DownloadTask downloadTask = new DownloadTask();
    v = inflater.inflate(R.layout.starters, container, false);
    tv_id = (TextView) v.findViewById(R.id.tv_starter_hide_id);
    tv_rating = (TextView) v.findViewById(R.id.tv_starter_hide_ratinf);
    tv_url = (TextView) v.findViewById(R.id.tv_starter_hide_url);
    cat = Category.Main_Cat;
    Log.i("Logcat Cat1", cat);
    switch (mCurrentPage) {
    case 1:
        Log.v("MyFragment Heap", "Max Mem in MB:"
                + (Runtime.getRuntime().maxMemory() / 1024 / 1024));
        // strUrl =
        // "http://vaibhavtech.com/work/android/get_json.php?cat="+cat+"&subcat=1";
        //strUrl = " http://vaibhavtech.com/work/android/movie_list.php?category=BollyWood%20&sub_category=top";
strUrl="http://vaibhavtech.com/work/android/json_topdownload.php?cat=Nature";       
        downloadTask.execute(strUrl);
        mListView = (GridView) v.findViewById(R.id.lv_countries);
        mListView.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1,
                    int pos, long arg3) {
                // TODO Auto-generated method stub
                Intent i = new Intent(getActivity().getBaseContext(),
                        Starter_info.class);
                i.putExtra("clicked_position", pos);
                startActivity(i);
            }
        });
        break;
    case 2:
        // strUrl =
        // "http://vaibhavtech.com/work/android/get_json.php?cat="+cat+"&subcat=1";
        strUrl="http://vaibhavtech.com/work/android/json_topdownload.php?cat=Nature";   
        //strUrl = " http://vaibhavtech.com/work/android/movie_list.php?category=BollyWood%20&sub_category=top";
        downloadTask.execute(strUrl);
        Log.v("Splash Heap", "Max Mem in MB:"
                + (Runtime.getRuntime().maxMemory() / 1024 / 1024));
        mListView = (GridView) v.findViewById(R.id.lv_countries);
        mListView.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1,
                    int pos, long arg3) {
                // TODO Auto-generated method stub
                Intent i = new Intent(getActivity().getBaseContext(),
                        Starter_info.class);
                i.putExtra("clicked_position", pos);
                startActivity(i);
            }
        });
        break;
    default:
        Log.i("Cat IS", Category.Main_Cat);
        // strUrl =
        strUrl="http://vaibhavtech.com/work/android/json_topdownload.php?cat=Nature";   
        // "http://vaibhavtech.com/work/android/get_json.php?cat="+cat+"&subcat=1";
        //strUrl = " http://vaibhavtech.com/work/android/movie_list.php?category=BollyWood%20&sub_category=top";
        downloadTask.execute(strUrl);
        Log.v("Splash Heap", "Max Mem in MB:"
                + (Runtime.getRuntime().maxMemory() / 1024 / 1024));
        mListView = (GridView) v.findViewById(R.id.lv_countries);
        mListView.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1,
                    int pos, long arg3) {
                // TODO Auto-generated method stub
                Intent i = new Intent(getActivity().getBaseContext(),
                        Starter_info.class);
                i.putExtra("clicked_position", pos);
                startActivity(i);
            }
        });
        break;
    }
    return v;
}

private String downloadUrl(String strUrl) throws IOException {
    String data = "";
    InputStream iStream = null;
    try {
        URL url = new URL(strUrl);
        // Creating an http connection to communicate with url
        HttpURLConnection urlConnection = (HttpURLConnection) url
                .openConnection();
        // Connecting to url
        urlConnection.connect();
        // Reading data from url
        iStream = urlConnection.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(
                iStream));
        StringBuffer sb = new StringBuffer();
        String line = "";
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }
        data = sb.toString();
        br.close();

    } catch (Exception e) {
        Log.d("Exception while downloading url", e.toString());
    } finally {
        iStream.close();
    }

    return data;
}

private class DownloadTask extends AsyncTask<String, Integer, String> {
    String data = null;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog=ProgressDialog.show(getActivity(), "", "Loading...");
    }
    @Override
    protected String doInBackground(String... url) {
        try {
            data = downloadUrl(url[0]);
            return data;
        } catch (Exception e) {
            Log.d("Background Task", e.toString());
            return null;
        }
    }

    @Override
    protected void onPostExecute(String result) {
        if(result!=null)
        {
            ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
            listViewLoaderTask.execute(result);
        }
        else
        {
            if(progressDialog!=null)
                progressDialog.dismiss();
            Log.d("Data Returns Null"," DownloadTask Terminated");
        }
    }
}

private class ListViewLoaderTask extends
        AsyncTask<String, Void, Boolean> {
    JSONObject jObject;
    @Override
    protected Boolean doInBackground(String... strJson) {

        try {
            jObject = new JSONObject(strJson[0]);
            // Getting the parsed data as a List construct
            StarterParser countryJsonParser = new StarterParser();
            MainActivity.WALL_PAPER_RESPONSE= countryJsonParser.parse(jObject);
        } catch (Exception e) {
            Log.d("Exception", e.toString());
        }
        return true;
    }

    @Override
    protected void onPostExecute(Boolean result) {
        if(progressDialog!=null)
            progressDialog.dismiss();
        if(result)
            mListView.setAdapter(new WallPaperAdapter(MainActivity.WALL_PAPER_RESPONSE));
    }
}

public class WallPaperAdapter extends BaseAdapter {

    private LayoutInflater mInflater = null;
    private List<HashMap<String, Object>> wall_paper_response = null;
    public WallPaperAdapter(List<HashMap<String, Object>> countries) {
        mInflater = LayoutInflater.from(getActivity());
        this.wall_paper_response=countries;
    }

    public int getCount() {
        return wall_paper_response.size();
    }

    public Object getItem(int position) {
        return position;
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolder holder;
        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.lv_layout,
                    null);
            holder = new ViewHolder();

            holder.txtId = (TextView) convertView
                    .findViewById(R.id.tv_starter_hide_id);
            //holder.txtDuration = (TextView) convertView
                //  .findViewById(R.id.tv_starter_hide_ratinf);
            holder.txtTitle= (TextView) convertView
                    .findViewById(R.id.tv_starter_hide_imagename);
            holder.txtYear = (TextView) convertView
                    .findViewById(R.id.tv_starter_hide_url);
            holder.imgPoster= (ImageView) convertView
                    .findViewById(R.id.iv_flag);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        try {
            holder.txtId.setText(wall_paper_response.get(position)
                            .get("id").toString());
            //holder.txtDuration.setText(wall_paper_response.get(position)
                //  .get("duration").toString());
            holder.txtTitle.setText(wall_paper_response.get(position)
                    .get("title").toString());
            holder.txtYear.setText(wall_paper_response.get(position)
                    .get("year").toString());
            Log.v("Image Loader URL",wall_paper_response.get(position)
                    .get("flag_path").toString());
            imageLoader.displayImage(wall_paper_response.get(position)
                            .get("flag_path").toString(),holder.imgPoster,options);

        } catch (Exception e) {
        }
        return convertView;
    }

    class ViewHolder {

        public TextView txtId;
    //  public TextView txtDuration;
        public TextView txtTitle;
        public TextView txtYear;
        public ImageView imgPoster;
    }
}
 }

I am making wallpaper app and my images are coming from json in gridview, its value are showing on logcat but not on screen what I do?

Answer 1

Since your json response contains string url.thus you need to download the image from that url and than only you can display it

Try this code,

Your class

ImageView lrImageView=(ImageView)findViewById(R.id.YOUR_IMAGE_ID);
ImageLoader task = new ImageLoader()
{
 @Override
 protected void onPostExecute(Bitmap result) 
 {
   lrImageView.setImageBitmap(result);
  }
};

task.execute(new String[]{strUrl});

and content of ImageLoader class is

public class ImageLoader extends AsyncTask<String,Void,Bitmap> 
{
@Override
protected Bitmap doInBackground(String... urls) 
{
    Bitmap map = null;
    for (String url : urls) 
    {
        map = downloadImage(url);
    }
    return map;
}

private Bitmap downloadImage(String url) 
{
    Bitmap bitmap = null;
    InputStream stream = null;
    BitmapFactory.Options bmOptions = new BitmapFactory.Options();
    bmOptions.inSampleSize = 1;
    try 
    {
        stream = getHttpConnection(url);
        bitmap = BitmapFactory.decodeStream(stream, null, bmOptions);
        stream.close();
    } 
    catch (IOException ex) {}
    return bitmap;
}

private InputStream getHttpConnection(String urlString)throws IOException 
{
    InputStream stream = null;
    URL url = new URL(urlString);
    URLConnection connection = url.openConnection();
    try 
    {
        HttpURLConnection httpConnection = (HttpURLConnection) connection;
        httpConnection.setRequestMethod("GET");
        httpConnection.connect();

        if (httpConnection.getResponseCode() == HttpURLConnection.HTTP_OK) 
        {
            stream = httpConnection.getInputStream();
        }
    } 
    catch (Exception ex) 
    {
        ex.printStackTrace();
    }
    return stream;
}

}

Answer 2

I have checked you JSON response which only contains the Image name only. Whereas it should contain the full path of your image where is resides. Then and only then it will get the actual location of image and will load the image.

You need to modify your json response for images values and provide the full path of the image besides the image name for the title value.

Try to update your JSON response like below:

{ "Demo": [ { "id": "1" ,"title": "http://www.vaibhavtech.com/work/android/1000.jpg" } ,
           { "id": "2" ,"title": "http://www.vaibhavtech.com/work/android/1001.jpg" } , 
          { "id": "3" ,"title": "http://www.vaibhavtech.com/work/android/1002.jpg" } ]}