uiview - How to do calculations only for visible cells in iPhone? -

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i have many cells in table view 500. each , every cells have own images , string paragraphs. draw images & strings of uiview's drawrect method. need calculate image , each string's position (including width & height measure cell height , wrapping areas). if did calculation @ time cells, takes time.. thats not good. want show cells quickly. want calculations visible cells , want show visible cells. calculation other cells should happend in background. 1 more thing, calculations once each cell. once did, store values in array. next time show things according array values, not calculations..

please me it... want know whether possible? if yes, procedure achieve it?

thanks in advance...

there no "procedure" this. uitableview behaves way. provide callbacks tell how many sections , rows-per-section there are, , how populate each cell. uitableview ask populate cells visible, , recycle cells when scroll off edge (as opposed creating them ad infinitum).


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