ios - Swift Async Imageloader -

-

i implement tableview cells display image. images loaded asynchroniously. better scrolling want request canceled if cell scrolls out of view. code far works, don't know how detect if cell visible or "scrolled over".

here's code:

    func tableview(tableview: uitableview, cellforrowatindexpath indexpath: nsindexpath) -> uitableviewcell {     let cell = tableview.dequeuereusablecellwithidentifier("eventstablecell", forindexpath: indexpath) as! eventstablecell     var elem : event = data[indexpath.row] event      cell.headlinelabel.text = elem.getname()     cell.secondlabel.text = elem.getdescription()      cell.progressview.setprogress(0.0,animated: true)      if let image = imagecache.getimage(elem.getid()) {         cell.coverimage.image = image         cell.progressview.removefromsuperview()     } else {         cell.coverimage.image = uiimage(named: "loading")         if(elem.getcover() == nil){             //noimage             cell.progressview.removefromsuperview()         }else{             println("start request for" + elem.getname()!)             cell.request = alamofire.request(.get, elem.getcover()!)                 .progress {                     (_, totalbytesread, totalbytesexpectedtoread) in                      dispatch_async(dispatch_get_main_queue()) {                         // 6                         cell.progressview.setprogress(float(totalbytesread) / float(totalbytesexpectedtoread), animated: true)                          // 7                         if totalbytesread == totalbytesexpectedtoread {                             cell.progressview.removefromsuperview()                         }                     }                 }                 .response { (request, response, data, error) in                     if error == nil && cell.coverimage.image != nil {                         imagecache.addimage(elem.getid(),image: uiimage(data: data!, scale:1)!)                         cell.coverimage.image = uiimage(data: data!, scale:1)                     }else{                      }             }         }     }     return cell }

and following code can cancel request:

cell.request!.cancel()

i noticed progressview isn't displayed sometimes, or maybe deleted superview early, maybe can help.

thanks tobias

cells reused table view performance reasons. same cell used lot of time different indexpath.

following line

tableview.dequeuereusablecellwithidentifier("eventstablecell", forindexpath: indexpath) as! eventstablecell

creates new eventstablecell object if there no 1 reused!

so progressview issue clear - remove cell calling 

cell.progressview.removefromsuperview()

but never add it. example add right after dequeuereusablecellwithidentifier call , remove later if needed. think in case better not remove/add hide/show instead:

cell.progressview.hidden = false

quite same image request - can call

cell.request?.cancel()

just after dequeuereusablecellwithidentifier

to make code more obvious can cancel in prepareforreuse method of eventstablecell have same effect.

prepareforreuse

prepares reusable cell reuse table view's delegate.


Comments

Post a Comment

Popular posts from this blog

html - Firefox flex bug applied to buttons? -

-
i'm trying apply flex button on firefox i'm having problem on chrome doesn't happens. this css: .button { display: inline-flex; align-items: center; } as can see in fiddle, "caret" word moved new line, happens if element <button> tag, <div> works expected. http://codepen.io/anon/pen/xblmgx is firefox bug or there css i'm missing? nevermind, looks "mr firefox" doesn't idea... <button> not implementable (by browsers) in pure css, bit of black box, perspective of css. means don't react in same way e.g. <div> would. this isn't specific flexbox -- e.g. don't render scrollbars if put "overflow:scroll" on button, , don't render table if put "display:table" on it. stepping further, isn't specific <button> . consider <fieldset> , <table> have special rendering behavior: data:text/html,<fieldset style="d...
Read more

html - Missing border-right in select on Firefox -

-
Image
when put select div width , padding-left, options have no border on right. more, happend if select have width 118px , parent have 15px of padding left! have idea, going on? my code: <!doctype html> <html> <head lang="en"> </head> <body> <div style="width: 1000px; padding-left: 15px;"> <select style="width: 118px;"> <option>a</option> <option>b</option> <option>c</option> </select> </div> </body> </html> and result: here plunker: click it happend on firefox on windows. tested on 40.0.2 version -webkit-box-sizing: border-box; -moz-box-sizing: border-box; -ms-box-sizing: border-box; box-sizing: border-box; source: https://stackoverflow.com/a/11390432/4431269 source of problem: https://bugzilla.mozilla.org/show_bug.cgi?id=924068 and use of google ! edit: (source of problem, explained) after rea...
Read more

python - build a suggestions list using fuzzywuzzy -

-
i building suggestion engine database. i'm using fuzzywuzzy module match user input string existing database shown below. if request.method == "get": display_dict = {} user_input = request.get["user_input"] # user input match_dict = {} food_items_obj = food_items.objects.all() # fetch objects table items in food_items_obj : match = fuzz.ratio(user_input.lower(),items.name.lower()) # try match user input existing names match_dict[match] = items.name # put 1 dictionary matched_dict = ordereddict(sorted(match_dict.items(),reverse = true)) # sort dictionary if max(matched_dict.keys()) == 100: # if exact match put in dict , return display_dict[100] = matched_dict[100] else : # if not found try best matching words.. ###########this part need help! ############# k,v in matched_dict.items(): if user_input in v : display_dict[k]...
Read more