swift3 - How to count number of uicollectionview's rows in swift -

i need determine uicollectionview's height.

let layout = contactcollectionview.collectionviewlayout let heightsize = string(int(layout.collectionviewcontentsize.height)) 

the above solution works on situations in project. in specific situation need count number of rows , multiple number find height.

func collectionview(_ collectionview: uicollectionview, numberofitemsinsection section: int) -> int {         // height = (count rows) * 30 . every cell height 30          // every cell has different width.         return (presenter?.selectedcontact.count)!     } 

how can find number of rows?

update

look @ image.

this collectionview. every cell has different width(because string). has different rows. width of collectionview width of view.frame

you can compare if collectionview's width greater total previous width(s) increment rowcounts one. assuming implementing uicollectionviewdelegateflowlayout methods , per each cell know dynamic width @ moment. if won't know width @ moment, can calculate width of string take considering uifont along other stuff in each cell.

here reference how calculate width of string https://stackoverflow.com/a/30450559/6106583

something below

//stored properties  var totalwidthperrow = cgfloat(0) var rowcounts = 0    let spacebetweencell = cgfloat(10) // whatever space between each cell    func collectionview(_collectionview:uicollectionview,layoutcollectionviewlayout:uicollectionviewlayout,sizeforitemat indexpath: indexpath) -> cgsize {     let collectionviewwidth = view.frame.width     let dynamiccellwidth = //whatever calculate width     totalwidthperrow += dynamiccellwidth + spacebetweencell      if (totalwidthperrow > collectionviewwidth) {       rowcounts += 1       totalwidthperrow = dynamiccellwidth + spacebetweencell    }    return cgsizemake(dynamiccellwidth , cgfloat(30)) }