如何使uicollectionview不使单元出队？

Question

I don't want cells to have to be generated when they come on screen for the first time. I also don't want cells that have gone off screen to have to be regenerated when they come back on the screen.

How can I have all the cells generated on loading the UICollectionView and stay that way as I scroll up and down?

Answer 1

You could manage your own list of cells (pre-create them based on the datasource, create any new ones as the datasource updates, and return the appropriate cell for the indexPath desired instead of dequeuing a cell inside cellForItemAtIndexPath) but as a general rule, that's a bad idea. You may have some specific case where cell configuration performance is poor, but the answer is usually "improve cell configuration" and rarely "keep everything in memory".

Speculating: If you're thinking of doing this in order to preserve state or cache some information in the cell, that's the wrong place to put it. The cell is presentation; keep that info in the datasource element so that whatever needs to be represented can be applied to whatever cell is being used right now.