iOS Delay loading network pictures

Downloading pictures on the Internet is very slow, in order to not affect the experience, choose to load the image delay is a good way. A tableview list, left temporarily without a diagram

-(UITableViewCell *) TableView: (UITableView *) TableView Cellforrowatindexpath: (nsindexpath*) Indexpath

{

static NSString *cellidentifier = @ "MyCell";

UITableViewCell *cell = [TableView dequeuereusablecellwithidentifier:cellidentifier];

if (cell = = nil)

{

cell = [[[UITableViewCell alloc] Initwithstyle:uitableviewcellstylesubtitle

Reuseidentifier:cellidentifier] autorelease];

Cell.selectionstyle = Uitableviewcellselectionstylenone;

}

Set up cell some data

Apprecord *apprecord = [Self.entries objectAtIndex:indexPath.row];

Cell.textLabel.text = Apprecord.appname;

Cell.detailTextLabel.text = apprecord.artist;

If no picture exists

if (!apprecord.appicon)

{

if (self.tableView.dragging = = no && self.tableView.decelerating = = no)//not in drag and deceleration, start downloading pictures

{

[Self Starticondownload:apprecord forindexpath:indexpath];

}

Set picture as a blank picture (Waiting for download)

Cell.imageView.image = [UIImage imagenamed:@ "Placeholder.png"];

}

If you have a picture

Else

{

Cell.imageView.image = Apprecord.appicon;

}

return cell;

}

 The point is[Self Starticondownload:apprecord forindexpath:indexpath];

-(void) Starticondownload: (Apprecord *) Apprecord Forindexpath: (Nsindexpath *) Indexpath

{

Icondownloader *icondownloader = [imagedownloadsinprogress Objectforkey:indexpath];

if (Icondownloader = = nil)//is already in the download does not have to repeat the download, did not go down in the download

{

Icondownloader = [[Icondownloader alloc] init];

Icondownloader.apprecord = Apprecord;

Icondownloader.indexpathintableview = Indexpath;

Icondownloader.delegate = self;

[Imagedownloadsinprogress Setobject:icondownloader Forkey:indexpath];

[Icondownloader Startdownload];

[Icondownloader release];

}

}

Icondownloader is a download picture encapsulation class Key method: Icondownloader.delegate = self; [Icondownloader Startdownload]; One is a delegate, in the future tell the self download to complete the update picture one is their own method to start the network download picture delegate call method, reset the picture

-(void) Appimagedidload: (Nsindexpath *) Indexpath

{

Icondownloader *icondownloader = [imagedownloadsinprogress Objectforkey:indexpath];

if (icondownloader! = nil)

{

UITableViewCell *cell = [Self.tableViewcellForRowAtIndexPath:iconDownloader.indexPathInTableView];

Cell.imageView.image = IconDownloader.appRecord.appIcon;

}

}

Methods in the class Icondownloader

-(void) startdownload

{

Self.activedownload = [Nsmutabledata data];

Nsurlconnection *conn = [[Nsurlconnection alloc] Initwithrequest:

[Nsurlrequest Requestwithurl:

[Nsurl URLWithString:appRecord.imageURLString]] Delegate:self];

Self.imageconnection = conn;

[Conn release];

}

Last Nsurlconnectionthe delegate needs to be implemented by itself.

iOS Delay loading network pictures