i new swift. trying show images in tableview. following tutorial.
in uitableview, shown in tutorial. storing images in cache. works fine if tableview has 1 section. how should set forkey value if have multiple sections in tableview?
how set value self.cache.setobject(image!, forkey:indexpath.row) according section , row? thanks!!
this code uitableview
func numberofsectionsintableview(tableview: uitableview) -> int { if(tableview == tableview){ return categoryarray.count }else{ return 1 } } func tableview(tableview : uitableview, titleforheaderinsection section: int)->string { if(tableview == tableview){ return categoryarray.objectatindex(section) as! string }else{ return "" } } func tableview(tableview: uitableview, numberofrowsinsection section: int) -> int { if(tableview == tableview){ print("count = \(mylist[section].count)") return mylist[section].count } else{ return 5 } } func tableview(tableview: uitableview, cellforrowatindexpath indexpath: nsindexpath) -> uitableviewcell { if(tableview == tableview) { let cell = tableview.dequeuereusablecellwithidentifier("cell", forindexpath: indexpath) as! customeventcell cell.cellbackgroundimg.image = uiimage(named: "placeholder") if (self.cache.objectforkey(indexpath.row) != nil){ print("cached image used, no need download it") cell.cellbackgroundimg?.image = self.cache.objectforkey(indexpath.row) as? uiimage }else{ let img_url = mylist[indexpath.section].objectatindex(indexpath.row).objectforkey("image") as? string if img_url != nil{ print("load image url") let url = nsurl(string: img_url!)! let request = nsmutableurlrequest(url:url) let defaultsession = nsurlsession(configuration: nsurlsessionconfiguration.defaultsessionconfiguration()) let task = defaultsession.datataskwithrequest(request, completionhandler: {(data:nsdata?, response:nsurlresponse?, error: nserror?) in dispatch_async(dispatch_get_main_queue(), { () -> void in let image = uiimage(data: data!) cell.cellbackgroundimg?.image = image self.cache.setobject(image!, forkey:indexpath.row) }) }) task.resume() } } return cell } }
you can use tag also. here code uses tag value. may need consider error handling in code.
func tableview(tableview: uitableview, cellforrowatindexpath indexpath: nsindexpath) -> uitableviewcell { var cell = uitableviewcell() if(tableview == tableview) { let customcell = tableview.dequeuereusablecellwithidentifier("cell", forindexpath: indexpath) as! customeventcell customcell.eventtitle.text = title customcell.cellbackgroundimg.image = uiimage(named: "placeholder") // calculate tagvalue , set cache objectforkey // here have taken big numbers same number not repeat let tagvalue = (indexpath.section * 100) + indexpath.row + 200 if (self.cache.objectforkey(tagvalue) != nil){ print("cached image used, no need download it") customcell.cellbackgroundimg?.image = self.cache.objectforkey(tagvalue) as? uiimage }else{ let img_url = mylist[indexpath.section].objectatindex(indexpath.row).objectforkey("image") as? string if img_url != nil{ print("load image url") let url = nsurl(string: img_url!)! let request = nsmutableurlrequest(url:url) let defaultsession = nsurlsession(configuration: nsurlsessionconfiguration.defaultsessionconfiguration()) let task = defaultsession.datataskwithrequest(request, completionhandler: {(data:nsdata?, response:nsurlresponse?, error: nserror?) in if error != nil { print(error) return }else if(data != nil){ dispatch_async(dispatch_get_main_queue(), { () -> void in let image = uiimage(data: data!) customcell.cellbackgroundimg?.image = image self.cache.setobject(image!, forkey:tagvalue) }) }else { print("error : image data nil") } }) task.resume() } else { print("error : image url nil") } } cell = customcell } return cell } 
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