UICollectionView: How to handle reloadData() and performBatchUpdates() together





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I have UIRefreshControl whose selector calls collectionView.reloadData(). My collectionView uses paginated API to load data on while scrolling. Hence I do collectionView.insertItems(at:indexpaths) to add next paginated data.



I am facing a problem when I scroll the collectionView to get next paginated data and refresh the collectionView. Hence the reload and insert will be called together, app crashes with the error message `




"attempt to insert item 9 into section 0, but there are only 9 items
in section 0 after the update"




`
How do I handle such situation gracefully?










share|improve this question























  • Why reload data is required when you are inserting row manually?

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 5:45











  • reloadData() is called when I refresh the collection view using UIRefreshControl. Refresh is user initiated. Hope you understood the question

    – rishu1992
    Nov 29 '18 at 6:02











  • I think problem is with datalist, which you are using to populate collectionview. You need to update datalist before reload.

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 6:12











  • It works fine if reloadData() and insertItem() user flow done seperately

    – rishu1992
    Nov 29 '18 at 6:44


















3















I have UIRefreshControl whose selector calls collectionView.reloadData(). My collectionView uses paginated API to load data on while scrolling. Hence I do collectionView.insertItems(at:indexpaths) to add next paginated data.



I am facing a problem when I scroll the collectionView to get next paginated data and refresh the collectionView. Hence the reload and insert will be called together, app crashes with the error message `




"attempt to insert item 9 into section 0, but there are only 9 items
in section 0 after the update"




`
How do I handle such situation gracefully?










share|improve this question























  • Why reload data is required when you are inserting row manually?

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 5:45











  • reloadData() is called when I refresh the collection view using UIRefreshControl. Refresh is user initiated. Hope you understood the question

    – rishu1992
    Nov 29 '18 at 6:02











  • I think problem is with datalist, which you are using to populate collectionview. You need to update datalist before reload.

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 6:12











  • It works fine if reloadData() and insertItem() user flow done seperately

    – rishu1992
    Nov 29 '18 at 6:44














3












3








3








I have UIRefreshControl whose selector calls collectionView.reloadData(). My collectionView uses paginated API to load data on while scrolling. Hence I do collectionView.insertItems(at:indexpaths) to add next paginated data.



I am facing a problem when I scroll the collectionView to get next paginated data and refresh the collectionView. Hence the reload and insert will be called together, app crashes with the error message `




"attempt to insert item 9 into section 0, but there are only 9 items
in section 0 after the update"




`
How do I handle such situation gracefully?










share|improve this question














I have UIRefreshControl whose selector calls collectionView.reloadData(). My collectionView uses paginated API to load data on while scrolling. Hence I do collectionView.insertItems(at:indexpaths) to add next paginated data.



I am facing a problem when I scroll the collectionView to get next paginated data and refresh the collectionView. Hence the reload and insert will be called together, app crashes with the error message `




"attempt to insert item 9 into section 0, but there are only 9 items
in section 0 after the update"




`
How do I handle such situation gracefully?







ios swift uicollectionview






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 29 '18 at 5:30









rishu1992rishu1992

6792724




6792724













  • Why reload data is required when you are inserting row manually?

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 5:45











  • reloadData() is called when I refresh the collection view using UIRefreshControl. Refresh is user initiated. Hope you understood the question

    – rishu1992
    Nov 29 '18 at 6:02











  • I think problem is with datalist, which you are using to populate collectionview. You need to update datalist before reload.

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 6:12











  • It works fine if reloadData() and insertItem() user flow done seperately

    – rishu1992
    Nov 29 '18 at 6:44



















  • Why reload data is required when you are inserting row manually?

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 5:45











  • reloadData() is called when I refresh the collection view using UIRefreshControl. Refresh is user initiated. Hope you understood the question

    – rishu1992
    Nov 29 '18 at 6:02











  • I think problem is with datalist, which you are using to populate collectionview. You need to update datalist before reload.

    – Kazi Abdullah Al Mamun
    Nov 29 '18 at 6:12











  • It works fine if reloadData() and insertItem() user flow done seperately

    – rishu1992
    Nov 29 '18 at 6:44

















Why reload data is required when you are inserting row manually?

– Kazi Abdullah Al Mamun
Nov 29 '18 at 5:45





Why reload data is required when you are inserting row manually?

– Kazi Abdullah Al Mamun
Nov 29 '18 at 5:45













reloadData() is called when I refresh the collection view using UIRefreshControl. Refresh is user initiated. Hope you understood the question

– rishu1992
Nov 29 '18 at 6:02





reloadData() is called when I refresh the collection view using UIRefreshControl. Refresh is user initiated. Hope you understood the question

– rishu1992
Nov 29 '18 at 6:02













I think problem is with datalist, which you are using to populate collectionview. You need to update datalist before reload.

– Kazi Abdullah Al Mamun
Nov 29 '18 at 6:12





I think problem is with datalist, which you are using to populate collectionview. You need to update datalist before reload.

– Kazi Abdullah Al Mamun
Nov 29 '18 at 6:12













It works fine if reloadData() and insertItem() user flow done seperately

– rishu1992
Nov 29 '18 at 6:44





It works fine if reloadData() and insertItem() user flow done seperately

– rishu1992
Nov 29 '18 at 6:44












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