public void prioritizeViewRange(int firstVisibleItem, int lastVisibleItem, int prefetchBuffer) {
if ((lastVisibleItem < firstVisibleItem) || (sectionKeys.size() == 0)) {
return;
}
// We want to prioritize requests for items which are visible but do not have pictures
// loaded yet. We also want to pre-fetch pictures for items which are not yet visible
// but are within a buffer on either side of the visible items, on the assumption that
// they will be visible soon. For these latter items, we'll store the images in memory
// in the hopes we can immediately populate their image view when needed.
// Prioritize the requests in reverse order since each call to prioritizeRequest will just
// move it to the front of the queue. And we want the earliest ones in the range to be at
// the front of the queue, so all else being equal, the list will appear to populate from
// the top down.
for (int i = lastVisibleItem; i >= 0; i--) {
SectionAndItem<T> sectionAndItem = getSectionAndItem(i);
if (sectionAndItem.graphObject != null) {
String id = getIdOfGraphObject(sectionAndItem.graphObject);
ImageRequest request = pendingRequests.get(id);
if (request != null) {
ImageDownloader.prioritizeRequest(request);
}
}
}
// For items which are not visible, but within the buffer on either side, we want to
// fetch those items and store them in a small in-memory cache of bitmaps.
int start = Math.max(0, firstVisibleItem - prefetchBuffer);
int end = Math.min(lastVisibleItem + prefetchBuffer, getCount() - 1);
ArrayList<T> graphObjectsToPrefetchPicturesFor = new ArrayList<T>();
// Add the IDs before and after the visible range.
for (int i = start; i < firstVisibleItem; ++i) {
SectionAndItem<T> sectionAndItem = getSectionAndItem(i);
if (sectionAndItem.graphObject != null) {
graphObjectsToPrefetchPicturesFor.add(sectionAndItem.graphObject);
}
}
for (int i = lastVisibleItem + 1; i <= end; ++i) {
SectionAndItem<T> sectionAndItem = getSectionAndItem(i);
if (sectionAndItem.graphObject != null) {
graphObjectsToPrefetchPicturesFor.add(sectionAndItem.graphObject);
}
}
for (T graphObject : graphObjectsToPrefetchPicturesFor) {
URI uri = getPictureUriOfGraphObject(graphObject);
final String id = getIdOfGraphObject(graphObject);
// This URL already have been requested for pre-fetching, but we want to act in an LRU manner,
// so move
// it to the end of the list regardless.
boolean alreadyPrefetching = prefetchedProfilePictureIds.remove(id);
prefetchedProfilePictureIds.add(id);
// If we've already requested it for pre-fetching, no need to do so again.
if (!alreadyPrefetching) {
downloadProfilePicture(id, uri, null);
}
}
}
public static <T> ArrayList<T> arrayList(T... ts) {
ArrayList<T> arrayList = new ArrayList<T>(ts.length);
for (T t : ts) {
arrayList.add(t);
}
return arrayList;
}
public static <T> List<T> asListNoNulls(T... array) {
ArrayList<T> result = new ArrayList<T>();
for (T t : array) {
if (t != null) {
result.add(t);
}
}
return result;
}
public List<T> getGraphObjectsById(Collection<String> ids) {
Set<String> idSet = new HashSet<String>();
idSet.addAll(ids);
ArrayList<T> result = new ArrayList<T>(idSet.size());
for (String id : idSet) {
T graphObject = graphObjectsById.get(id);
if (graphObject != null) {
result.add(graphObject);
}
}
return result;
}
private void processImageResponse(
ImageResponse response, String graphObjectId, ImageView imageView) {
pendingRequests.remove(graphObjectId);
if (response.getError() != null) {
callOnErrorListener(response.getError());
}
if (imageView == null) {
// This was a pre-fetch request.
if (response.getBitmap() != null) {
// Is the cache too big?
if (prefetchedPictureCache.size() >= MAX_PREFETCHED_PICTURES) {
// Find the oldest one and remove it.
String oldestId = prefetchedProfilePictureIds.remove(0);
prefetchedPictureCache.remove(oldestId);
}
prefetchedPictureCache.put(graphObjectId, response);
}
} else if (graphObjectId.equals(imageView.getTag())) {
Exception error = response.getError();
Bitmap bitmap = response.getBitmap();
if (error == null && bitmap != null) {
imageView.setImageBitmap(bitmap);
imageView.setTag(response.getRequest().getImageUri());
}
}
}
private void onFriendPickerDone(FriendPickerFragment fragment) {
FragmentManager fm = getSupportFragmentManager();
fm.popBackStack();
String results = "";
Collection<GraphUser> selection = fragment.getSelection();
if (selection != null && selection.size() > 0) {
ArrayList<String> names = new ArrayList<String>();
for (GraphUser user : selection) {
names.add(user.getName());
}
results = TextUtils.join(", ", names);
} else {
results = "no friends";
}
showAlert("rar", results);
}
