UICollectionview datas loading issue - ios

Question

Hi i have implemented UICollectionView in my app..If my array count value greater than 20 and when i tried to scroll the view it was not showing previous datas,,
In cellForItemAtIndexPath:(NSIndexPath *)indexPath method every time i check
if (indexPath.row == [recipeImages count] - 1)
{
[self loadDatas];
}
method.So that i could download 10 datas everytime...
-(UICollectionViewCell *)collectionView:(UICollectionView*)collectionViewcellForItemAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *identifier = #"CourseList";
NSLog(#"indexpath %# in cell for row",indexPath);
CollectionCellContent *cell = (CollectionCellContent*)[collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
NSDictionary *course;
course=[courselist objectAtIndex:indexPath.row];
cell.coursename.text=[course objectForKey:#"course_name"];
cell.authorname.text=[course objectForKey:#"course_author"];
cell.price.text=[course objectForKey:#"course_price"];
cell.cover.image=[UIImage imageNamed:[course objectForKey:#"course_cover_image"]];
cell.review.image=[UIImage imageNamed:[course objectForKey:#"ratings"]];
NSString *imageUrlString = [[NSString alloc]initWithFormat:#"%#/%#/%#",delegate.course_image_url,[course objectForKey:#"course_id"],[course objectForKey:#"course_cover_image"]];
UIImage *imageFromCache = [self.imageCache objectForKey:imageUrlString];
if (imageFromCache) {
cell.cover.image= imageFromCache;
}
else
{
cell.cover.image = [UIImage imageNamed:#"placeholder"];
[self.imageOperationQueue addOperationWithBlock:^{
NSURL *imageurl = [NSURL URLWithString:imageUrlString];
UIImage *img = [UIImage imageWithData:[NSData dataWithContentsOfURL:imageurl]];
if (img != nil) {
[self.imageCache setObject:img forKey:imageUrlString];
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
CollectionCellContent *updateCell = (CollectionCellContent*)[self.ipadcollection cellForItemAtIndexPath:indexPath];
if (updateCell) {
[updateCell.cover setImage:img];
}
}];
}
}];
}
if (indexPath.row == [courselist count] - 1)
[self loadDatas];
return cell;
}
in load datas method:
[categorylist addObject:[arrayList1 objectForKey:#"category_name"]];
[category_tableView reloadData];
whenever i call reload data method i am facing this issue..
-(void)loadDatas
{
NSString *urltemp=[[databaseurl sharedInstance]DBurl];
NSString *url1=#"AllCourse.php";
NSString *URLString=[NSString stringWithFormat:#"%#%#?offset=%d",urltemp,url1,offset];
NSMutableArray *search = [du MultipleCharacters:URLString];
NSDictionary* menu = [search valueForKey:#"serviceresponse"];
NSArray *Listofdatas=[menu objectForKey:#"Course List"];
NSMutableArray *temp1=[[NSMutableArray alloc]init];
if ([Listofdatas count]>0)
{
for (int i=0;i<[Listofdatas count];i++)
{
NSDictionary *arrayList1= [Listofdatas objectAtIndex:i];
NSDictionary* temp=[arrayList1 objectForKey:#"serviceresponse"];
// NSLog(#"Received Values %#",temp);
if (offset==0) {
[courselist addObject:temp];
}
else
[temp1 addObject:temp];
}
if (offset!=0)
{
NSMutableArray *arrayWithIndexPaths = [NSMutableArray array];
for (NSInteger index =courselist.count; index < (courselist.count + temp1.count); index++) {
[arrayWithIndexPaths addObject:[NSIndexPath indexPathForRow:index inSection:0]];
}
if (courselist) {
[courselist addObjectsFromArray:temp1];
[self.ipadcollection performBatchUpdates:^{
[self.ipadcollection insertItemsAtIndexPaths:arrayWithIndexPaths];
}
completion:nil];
// [self.collectionView reloadData];
}
else {
courselist = [[NSMutableArray alloc] initWithArray:temp1];
}
}
if (![HUD isHidden]) {
[HUD hide:YES];
}
}
offset+=10;
[self.ipadcollection reloadData];
}

Answer 1

Make some delay before reloading UICollectionView.
[self performSelector:#selector(reloaddatas) withObject:nil afterDelay:0.5f];