private void loadDataSkippingRoundTripIfCached() {
clearResults();
Request request = getRequestForLoadData(getSession());
if (request != null) {
onLoadingData();
loadingStrategy.startLoading(request);
}
}
@Override
public void onDetach() {
super.onDetach();
listView.setOnScrollListener(null);
listView.setAdapter(null);
loadingStrategy.detach();
sessionTracker.stopTracking();
}
@Override
public void attach(GraphObjectAdapter<GraphPlace> adapter) {
super.attach(adapter);
this.adapter.setDataNeededListener(
new GraphObjectAdapter.DataNeededListener() {
@Override
public void onDataNeeded() {
// Do nothing if we are currently loading data . We will get notified again when that
// load finishes if the adapter still
// needs more data. Otherwise, follow the next link.
if (!loader.isLoading()) {
loader.followNextLink();
}
}
});
}
private void clearResults() {
if (adapter != null) {
boolean wasSelection = !selectionStrategy.isEmpty();
boolean wasData = !adapter.isEmpty();
loadingStrategy.clearResults();
selectionStrategy.clear();
adapter.notifyDataSetChanged();
// Tell anyone who cares the data and selection has changed, if they have.
if (wasData && onDataChangedListener != null) {
onDataChangedListener.onDataChanged(PickerFragment.this);
}
if (wasSelection && onSelectionChangedListener != null) {
onSelectionChangedListener.onSelectionChanged(PickerFragment.this);
}
}
}
@Override
public void onActivityCreated(final Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
sessionTracker =
new SessionTracker(
getActivity(),
new Session.StatusCallback() {
@Override
public void call(Session session, SessionState state, Exception exception) {
if (!session.isOpened()) {
// When a session is closed, we want to clear out our data so it is not visible to
// subsequent users
clearResults();
}
}
});
setSettingsFromBundle(savedInstanceState);
loadingStrategy = createLoadingStrategy();
loadingStrategy.attach(adapter);
selectionStrategy = createSelectionStrategy();
selectionStrategy.readSelectionFromBundle(savedInstanceState, SELECTION_BUNDLE_KEY);
// Should we display a title bar? (We need to do this after we've retrieved our bundle
// settings.)
if (showTitleBar) {
inflateTitleBar((ViewGroup) getView());
}
if (activityCircle != null && savedInstanceState != null) {
boolean shown = savedInstanceState.getBoolean(ACTIVITY_CIRCLE_SHOW_KEY, false);
if (shown) {
displayActivityCircle();
} else {
// Should be hidden already, but just to be sure.
hideActivityCircle();
}
}
}
@Override
protected void onLoadFinished(
GraphObjectPagingLoader<GraphPlace> loader, SimpleGraphObjectCursor<GraphPlace> data) {
super.onLoadFinished(loader, data);
// We could be called in this state if we are clearing data or if we are being re-attached
// in the middle of a query.
if (data == null || loader.isLoading()) {
return;
}
hideActivityCircle();
if (data.isFromCache()) {
// Only the first page can be cached, since all subsequent pages will be round-tripped.
// Force
// a refresh of the first page before we allow paging to begin. If the first page produced
// no data, launch the refresh immediately, otherwise schedule it for later.
loader.refreshOriginalRequest(
data.areMoreObjectsAvailable() ? CACHED_RESULT_REFRESH_DELAY : 0);
}
}
/**
* Causes the picker to load data from the service and display it to the user.
*
* @param forceReload if true, data will be loaded even if there is already data being displayed
* (or loading); if false, data will not be re-loaded if it is already displayed (or loading)
*/
public void loadData(boolean forceReload) {
if (!forceReload && loadingStrategy.isDataPresentOrLoading()) {
return;
}
loadDataSkippingRoundTripIfCached();
}