I am trying to get user albums using the FB SDK. I managed to log in successfully and I can get a user profile picture and get an access token.
I follow this answer here and try to get it working, but I have a problem when I get java.lang.NullPointerException in the adapter class on at com.myapp.myapp.PhotosAdapter.getCount(PhotosAdapter.java:37)
Here's the full setup of what I have:
Where am I mistaken? thanks
FBGRID Activity:
public class FBGRID extends Activity { private String URL; // STORE THE PAGING URL private String pagingURL; // FLAG FOR CURRENT PAGE int current_page = 1; // BOOLEAN TO CHECK IF NEW FEEDS ARE LOADING Boolean loadingMore = true; Boolean stopLoadingData = false; GridView grid; ArrayList<getPhotos> arrPhotos; PhotosAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_fbgrid); grid = (GridView) findViewById(R.id.gridView1); grid.setOnScrollListener(new OnScrollListener() { @Override public void onScrollStateChanged(AbsListView view, int scrollState) { } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { int lastInScreen = firstVisibleItem + visibleItemCount; if ((lastInScreen == totalItemCount) && !(loadingMore)) { if (stopLoadingData == false) { // FETCH THE NEXT BATCH OF FEEDS new loadMorePhotos().execute(); } } } }); new getPhotosData().execute(); } private class getPhotosData extends AsyncTask<Void, Void, Void> { @Override protected Void doInBackground(Void... arg0) { // CHANGE THE LOADING MORE STATUS TO PREVENT DUPLICATE CALLS FOR // MORE DATA WHILE LOADING A BATCH loadingMore = true; Session s = Session.getActiveSession(); // SET THE INITIAL URL TO GET THE FIRST LOT OF ALBUMS URL = "https://graph.facebook.com/" + "me/albums" + "/photos&access_token=" + s.getAccessToken() + "?limit=10"; try { HttpClient hc = new DefaultHttpClient(); HttpGet get = new HttpGet(URL); HttpResponse rp = hc.execute(get); if (rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { String queryAlbums = EntityUtils.toString(rp.getEntity()); JSONObject JOTemp = new JSONObject(queryAlbums); JSONArray JAPhotos = JOTemp.getJSONArray("data"); // IN MY CODE, I GET THE NEXT PAGE LINK HERE getPhotos photos; for (int i = 0; i < JAPhotos.length(); i++) { JSONObject JOPhotos = JAPhotos.getJSONObject(i); // Log.e("INDIVIDUAL ALBUMS", JOPhotos.toString()); if (JOPhotos.has("link")) { photos = new getPhotos(); // GET THE ALBUM ID if (JOPhotos.has("id")) { photos.setPhotoID(JOPhotos.getString("id")); } else { photos.setPhotoID(null); } // GET THE ALBUM NAME if (JOPhotos.has("name")) { photos.setPhotoName(JOPhotos.getString("name")); } else { photos.setPhotoName(null); } // GET THE ALBUM COVER PHOTO if (JOPhotos.has("picture")) { photos.setPhotoPicture(JOPhotos .getString("picture")); } else { photos.setPhotoPicture(null); } // GET THE PHOTO SOURCE if (JOPhotos.has("source")) { photos.setPhotoSource(JOPhotos .getString("source")); } else { photos.setPhotoSource(null); } arrPhotos.add(photos); } } } } catch (Exception e) { e.printStackTrace(); } return null; } @Override protected void onPostExecute(Void result) { grid.setAdapter(new PhotosAdapter(FBGRID.this, arrPhotos)); loadingMore = false; } } private class loadMorePhotos extends AsyncTask<Void, Void, Void> { @Override protected Void doInBackground(Void... arg0) { // SET LOADING MORE "TRUE" loadingMore = true; // INCREMENT CURRENT PAGE current_page += 1; // Next page request URL = pagingURL; try { HttpClient hc = new DefaultHttpClient(); HttpGet get = new HttpGet(URL); HttpResponse rp = hc.execute(get); if (rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { String queryAlbums = EntityUtils.toString(rp.getEntity()); // Log.e("PAGED RESULT", queryAlbums); JSONObject JOTemp = new JSONObject(queryAlbums); JSONArray JAPhotos = JOTemp.getJSONArray("data"); // IN MY CODE, I GET THE NEXT PAGE LINK HERE getPhotos photos; for (int i = 0; i < JAPhotos.length(); i++) { JSONObject JOPhotos = JAPhotos.getJSONObject(i); // Log.e("INDIVIDUAL ALBUMS", JOPhotos.toString()); if (JOPhotos.has("link")) { photos = new getPhotos(); // GET THE ALBUM ID if (JOPhotos.has("id")) { photos.setPhotoID(JOPhotos.getString("id")); } else { photos.setPhotoID(null); } // GET THE ALBUM NAME if (JOPhotos.has("name")) { photos.setPhotoName(JOPhotos.getString("name")); } else { photos.setPhotoName(null); } // GET THE ALBUM COVER PHOTO if (JOPhotos.has("picture")) { photos.setPhotoPicture(JOPhotos .getString("picture")); } else { photos.setPhotoPicture(null); } // GET THE ALBUM PHOTO COUNT if (JOPhotos.has("source")) { photos.setPhotoSource(JOPhotos .getString("source")); } else { photos.setPhotoSource(null); } arrPhotos.add(photos); } } } } catch (Exception e) { e.printStackTrace(); } return null; } @Override protected void onPostExecute(Void result) { // get listview current position - used to maintain scroll position int currentPosition = grid.getFirstVisiblePosition(); // APPEND NEW DATA TO THE ARRAYLIST AND SET THE ADAPTER TO THE // LISTVIEW adapter = new PhotosAdapter(FBGRID.this, arrPhotos); grid.setAdapter(adapter); // Setting new scroll position grid.setSelection(currentPosition + 1); // SET LOADINGMORE "FALSE" AFTER ADDING NEW FEEDS TO THE EXISTING // LIST loadingMore = false; } } public class getPhotos { String PhotoID; String PhotoName; String PhotoPicture; String PhotoSource; // SET THE PHOTO ID public void setPhotoID(String PhotoID) { this.PhotoID = PhotoID; } // GET THE PHOTO ID public String getPhotoID() { return PhotoID; } // SET THE PHOTO NAME public void setPhotoName(String PhotoName) { this.PhotoName = PhotoName; } // GET THE PHOTO NAME public String getPhotoName() { return PhotoName; } // SET THE PHOTO PICTURE public void setPhotoPicture(String PhotoPicture) { this.PhotoPicture = PhotoPicture; } // GET THE PHOTO PICTURE public String getPhotoPicture() { return PhotoPicture; } // SET THE PHOTO SOURCE public void setPhotoSource(String PhotoSource) { this.PhotoSource = PhotoSource; } // GET THE PHOTO SOURCE public String getPhotoSource() { return PhotoSource; } } }
and for the Adapter class (it uses the image loading library ):
final class PhotosAdapter extends BaseAdapter { private Activity activity; ArrayList<getPhotos> arrayPhotos; private static LayoutInflater inflater = null; ImageLoader imageLoader; public PhotosAdapter(Activity a, ArrayList<getPhotos> arrPhotos) { activity = a; arrayPhotos = arrPhotos; inflater = (LayoutInflater) activity .getSystemService(Context.LAYOUT_INFLATER_SERVICE); imageLoader = new ImageLoader(activity.getApplicationContext()); } public int getCount() { return arrayPhotos.size(); } public Object getItem(int position) { return arrayPhotos.get(position); } public long getItemId(int position) { return position; } public View getView(final int position, View convertView, ViewGroup parent) { ViewHolder holder; View vi = convertView; if (convertView == null) { vi = inflater.inflate(R.layout.photos_item, null); holder = new ViewHolder(); holder.imgPhoto = (ImageView) vi.findViewById(R.id.grid_item_image); vi.setTag(holder); } else { holder = (ViewHolder) vi.getTag(); } if (arrayPhotos.get(position).getPhotoPicture() != null) { imageLoader.DisplayImage(arrayPhotos.get(position) .getPhotoPicture(), holder.imgPhoto); } return vi; } static class ViewHolder { ImageView imgPhoto; } }
Here logcat:
FATAL EXCEPTION: main java.lang.NullPointerException at com.myapp.myapp.PhotosAdapter.getCount(PhotosAdapter.java:37) at android.widget.GridView.setAdapter(GridView.java:186) at com.myapp.myapp.FBGRID$getPhotosData.onPostExecute(FBGRID.java:173) at com.myapp.myapp.FBGRID$getPhotosData.onPostExecute(FBGRID.java:1) at android.os.AsyncTask.finish(AsyncTask.java:631) at android.os.AsyncTask.access$600(AsyncTask.java:177) at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:213) at android.app.ActivityThread.main(ActivityThread.java:5225) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:525) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:741) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557) at dalvik.system.NativeStart.main(Native Method)