ios - didSelectItemAtIndexPath modifying multiple cells in UICollectionView -

i have collection view 30 items, , want perform on press. in way:

func collectionview(collectionview: uicollectionview, didselectitematindexpath indexpath: nsindexpath) {      let cell = collectionview.cellforitematindexpath(indexpath) as! itemcell      var translucentview = iltranslucentview(frame: cgrectmake(0, 0, cell.contentview.frame.size.width, cell.contentview.frame.size.height))     translucentview.translucentalpha = 0.9     translucentview.translucentstyle = uibarstyle.blacktranslucent     translucentview.translucenttintcolor = uicolor.clearcolor()     translucentview.backgroundcolor = uicolor.clearcolor()     translucentview.alpha = 0.0     cell.contentview.addsubview(translucentview)     uiview.animatewithduration(0.4, animations: {         translucentview.alpha = 1.0     }) } 

the function works expected, view appears not on tapped cell, on cell in same position not visible on screen. if there 3 visible cells on screen , tap on number 1, when scroll view has been added cell 4, 7, etc...

uicollectionview re-use cells uitableview. when cell scrolled offscreen added queue, , re-used next cell scrolled onscreen(e.g. cell 4, 7 ...).

simply removing translucentview solve issue:

uiview.animatewithduration(0.4, animations: { () -> void in     translucentview.alpha = 1.0 }) { (finish) -> void in     translucentview.removefromsuperview() } 

you can create translucentview in itemcell , update status in cellforitematindexpath method:

override func collectionview(collectionview: uicollectionview, cellforitematindexpath indexpath: nsindexpath) -> uicollectionviewcell {     let cell = collectionview.dequeuereusablecellwithreuseidentifier(cellidentifier, forindexpath: indexpath) as! itemcell      if find(collectionview.indexpathsforselecteditems() as! [nsindexpath], indexpath) != nil {         cell.translucentview.alpha = 1.0     } else {         cell.translucentview.alpha = 0.0     }      return cell }  override func collectionview(collectionview: uicollectionview, didselectitematindexpath indexpath: nsindexpath) {      let cell = collectionview.cellforitematindexpath(indexpath) as! itemcell      uiview.animatewithduration(0.4, animations: {         cell.translucentview.alpha = 1.0     }) }  override func collectionview(collectionview: uicollectionview, diddeselectitematindexpath indexpath: nsindexpath) {     let cell = collectionview.cellforitematindexpath(indexpath) as! itemcell      uiview.animatewithduration(0.4, animations: {         cell.translucentview.alpha = 0.0     }) }