iPhone: some UITableView's cells appears blank in edit

I use tableView with custom cells and for cell drawing I use drawRect: method for scrolling performance. In edi开发者_运维百科t mode when I move cells move and down sometimes some cells appear blank. And during scrolling also random cells start appear blank.Please look attached images. Can someone help to understand problem?

if you are using dequeueReusableCellForIdentifier then try removing that. I mean to say alloc a new cell every time.

I am suggesting above based on assumption that your cell contains some heavy data which takes time in drawing. In this case if you reuse cell then it will take cell that goes out of visible screen and will paint draw new data in it.

If this doesn't help then please post some code showing how you are creating custom cell.