问题
I see UIScrollView has a method to predict final content offset
scrollViewWillEndDragging:withVelocity:targetContentOffset:
and since UITableView is also a UIScrollView, So I want to use this value to calculate the destination Cell while the view is still scrolling/decelerating
I'm trying to loop through all the data and sum up the section headers, cell heights, section footers until the sum exceeds target Content offset. Would it work or is there a better way to do so?
Thanks in advance, any help is appreciated!
Leo
回答1:
Don't use that method to predict where your table view will end up and try to guess which cells to load content for. Optimising table scrolling, particularly the loading of images, is a well-known problem. Check out this WWDC Video (developer registration required) and Apple's sample LazyTableImages project. Basically, you start background operations to load your cell contents, and update the cells (if they are still on the screen) once your content is loaded. In the meantime, you show placeholder content.
If you do it the way you intend, you will only ever have the target cells populated,which will look odd as you are scrolling past cells that have never been the target.
来源：https://stackoverflow.com/questions/12381711/predict-table-view-scroll-destination-indexpath