NullPointerException when downloading image

Question

I am trying to display an image from the Internet to the ImageView but getting NullPointerException.

error log:

java.lang.NullPointerException at com.example.user.labone.MainActivity$DownloadImageTask.onPostExecute(MainActivity.java:176)

code:

public class MainActivity extends ActionBarActivity {

    String jsonString;

    private static final String TAG_RESULTS="result";
    private static final String TAG_ID = "id";
    private static final String TAG_TITLE = "title";
    private static final String TAG_IMG= "src";
    private static final String TAG_DESC ="desc";

    JSONArray dataArray = null;

    ArrayList<HashMap<String, String>> dataArrayList;

    ListView list;
    ImageView imageView;

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

        list = (ListView) findViewById(R.id.listView);
        //imageView=(ImageView) findViewById(R.id.imageView);

        dataArrayList = new ArrayList<HashMap<String,String>>();
        getData();
    }


    protected void showList(){
        try {
            JSONObject jsonObj = new JSONObject(jsonString);
            dataArray = jsonObj.getJSONArray(TAG_RESULTS);

            for(int i = 0; i< dataArray.length(); i++){
                JSONObject c = dataArray.getJSONObject(i);
                String idString = c.getString(TAG_ID);
                String titleString = c.getString(TAG_TITLE);
                String imgString = c.getString(TAG_IMG);
                String descString = c.getString(TAG_DESC);

                HashMap<String,String> dataHashMap = new HashMap<String,String>();

                dataHashMap.put(TAG_ID,idString);
                dataHashMap.put(TAG_TITLE,titleString);
                dataHashMap.put(TAG_IMG,imgString);
                dataHashMap.put(TAG_DESC,descString);

                // show The Image
                new DownloadImageTask((ImageView) findViewById(R.id.imageViewID)).execute("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png");
                Log.i("TAG", imgString);

                dataArrayList.add(dataHashMap);
            }

            ListAdapter adapter = new SimpleAdapter(
                    MainActivity.this, dataArrayList, R.layout.list_item,
                    new String[]{TAG_ID, TAG_TITLE, TAG_DESC},
                    new int[]{R.id.id, R.id.title, R.id.desc}
            );

            list.setAdapter(adapter);

        } catch (JSONException e) {
            e.printStackTrace();
        }

    }

    public void getData(){
        class GetDataJSON extends AsyncTask<String, Void, String>{

            @Override
            protected String doInBackground(String... params) {
                DefaultHttpClient httpclient = new DefaultHttpClient(new BasicHttpParams());
                HttpPost httppost = new HttpPost("http://geekysoft.com.pk/labone/labone_conn.php");

                // Depends on your web service
                httppost.setHeader("Content-type", "application/json");

                InputStream inputStream = null;
                String result = null;
                try {
                    HttpResponse response = httpclient.execute(httppost);
                    HttpEntity entity = response.getEntity();

                    inputStream = entity.getContent();
                    // json is UTF-8 by default
                    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
                    StringBuilder sb = new StringBuilder();

                    String line = null;
                    while ((line = reader.readLine()) != null)
                    {
                        sb.append(line + "\n");
                    }
                    result = sb.toString();
                } catch (Exception e) {
                    // Oops
                }
                finally {
                    try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
                }
                return result;
            }

            @Override
            protected void onPostExecute(String result){
                jsonString =result;
                showList();
            }
        }
        GetDataJSON g = new GetDataJSON();
        g.execute();
    }

    private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
        ImageView bmImage;

        public DownloadImageTask(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        @Override
        protected Bitmap doInBackground(String... urls) {
            String urldisplay = urls[0];
            Bitmap mIcon11 = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon11 = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            Log.i("BITMAP", "BITMAP SIZE IS : " + mIcon11.getByteCount());
            return mIcon11;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }
}

id is fine and i missed the extension while pasting the code.. still getting nullpointerexception — Nelson John, Sep 04 '16 at 10:14
Do you see this log `Log.e("Error", e.getMessage());` in your logcat? your inputStream is maybe null, can you check that for me plz? — Rachik Abidi, Sep 04 '16 at 10:23
Before `return mIcon11;`, can you check if the bitmap is filled by adding this simple log `Log.e("BITMAP", "BITMAP SIZE IS : " + mIcon11.getByteCount());`. Just tell me the result :) — Rachik Abidi, Sep 04 '16 at 10:31
@RachikAbidi i have added my mainactivity code and i dont know why log "Bitmap" is not printed — Nelson John, Sep 04 '16 at 10:41
where are you trying to find your image? Isn't that image part of the item in the list? Shouldn't you call findById on the list item? — kingston, Sep 04 '16 at 11:25
@kingston i am trying to find the image in showList() with id "imageViewID" — Nelson John, Sep 04 '16 at 12:18
right but that would look for the image in the view of the activity. Please check the code in my answer to get an idea of what you need to do — kingston, Sep 04 '16 at 12:24
think about this: if you have multiple items which image should your find return? — kingston, Sep 04 '16 at 12:25

kingston · Accepted Answer · 2016-09-04T20:24:51.347

(ImageView) findViewById(R.id.imageViewID) is returning null

You need a custom Adapter that should look like the following but please consider this example just as a way to show you the kind of things you need to do: there are better way to do it like using the ViewHolder pattern.

public class ListWithImageAdapter extends ArrayAdapter<String>{

    private final Context mContext;
    private final String[] mTexts;

    public ListWithImageAdapter(Context context, String[] texts) {
        super(context, R.layout.list_item_payment_type, texts);
        mContext = context;
        mTexts = texts;
    }

    @Override
    public View getView(int position, View view, ViewGroup parent) {
        View rowView= LayoutInflater.from(mContext).inflate(R.layout.list_item, null, true);

        ImageView imageView = (ImageView) rowView.findViewById(R.id.img); // here you get the image

        return rowView;
    }
}

Have you heard about Picasso and Glide? Please Google it...

NullPointerException when downloading image

1 Answers1