Proper way to display UICollectionView with paging - ios

Question

I've read many many SO solutions about UICollectionView with paging. I myself also work with those solutions:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat pageWidth = self.collectionView.frame.size.width;
self.lbPaging.text = [NSString stringWithFormat:#"%d/%d", self.collectionView.contentOffset.x / pageWidth, totalPage];
}
OR
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
CGFloat pageWidth = self.collectionView.frame.size.width;
self.lbPaging.text = [NSString stringWithFormat:#"%d/%d", self.collectionView.contentOffset.x / pageWidth, totalPage];
}
Yeah, this work fine most the time. But now I experienced something unexpected:
When user scroll fast enough, it'll get past the method above, which may cause the paging malfunction (like 15/13 at the last page, or showing 3/5 even though it's the first page).
Precisely for us developer or tester, to reproduce this bug, keep your finger touch on the scroll view and start to scroll. When you're nearly out of the edge (where normally, you'll release your finger), touch the other side of the edge and keep scrolling. It's easier to reproduce on real device.
So I'm asking if anyone know a proper way to display the page navigation? Well, without UIPageViewController (I'd like to display the numeric page, not the dots).
EDIT
I don't know if this problem is critical or not, but I think maybe it is, because I'm performing loading data when scrolling to next page. Recently, I've got crash at this (it's really hard to debug, like at which step it got crash):
[self.collectionView performBatchUpdates:^{
NSMutableArray *arrayWithIndexPaths = [NSMutableArray array];
for (NSInteger index = 0; index < next2page.count; index++ ) {
[arrayWithIndexPaths addObject:[NSIndexPath indexPathForRow:(index + offset) inSection:0]];
}
[self.collectionView insertItemsAtIndexPaths:arrayWithIndexPaths];
} completion:nil];
Exception is something like this: Fail to insert items to index path in section 0 (has only 69 row, insert to indexPath:73)

Answer 1

hello i have create button in UICollectionView like load more data and function is given below:-
- (void)viewDidLoad {
//declare page inedex initial base 0.
self.pageIndex = 0;
[self loadMoreData];
}
after you call load more data function page index will increase here i want my page index like 0,20,40 so i have create self.pageIndex+= 20 u can change according to your want
-(void)loadMoreData
{
self.isFromMoreData = TRUE;
self.pageIndex+= 20;
NSLog(#"loadMoreData %d and self.index %d",self.pageIndex,self.index);
[self loadDataIntoCollectionView];//this function calls api
}
******************another way is given below*******************************
use UIRefreshControl.
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
refreshControl = refreshControl;
refreshControl.backgroundColor = [UIColor whiteColor];
refreshControl.tintColor = [UIColor grayColor];
[refreshControl addTarget:self action:#selector(loadMoreData) forControlEvents:UIControlEventValueChanged];
self.myCollectionView.pagingEnabled = YES;
[self.myCollectionView addSubview:refreshControl];
self.myCollectionView.alwaysBounceVertical = YES;
and call the same function loadMoreData that i have declare above.
Hope this help you...
please referred my image