NSURLConnection not "firing" until UITableView scrolls..
- by Simon
Hi,
I've got a UITableView that loads an image asynchronously and places it in the UITableViewCell once it's loaded (I'm using almost the exact same code as in the "LazyTableImages" tutorial). This works fine for all images when I scroll the table, but it's not loading the images that are first in the view.
The code is definitely working fine as the class that actually sends the NSURLConnection request is being called correctly (I added an NSLog and it reached the console). The NSURLConnection is just not calling the delegate methods (didReceiveData, connectionDidFinishLoading, etc).
Here's my code:
HomeController.m
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
NSArray *feed = [feeds objectAtIndex: indexPath.row];
/**
* Name of person
*/
[...]
/**
* Feed entry
*/
[...]
/**
* Misc work
*/
[...]
}
FeedRecord *feedRecord = [self.entries objectAtIndex:indexPath.row];
if( !feedRecord.image ) {
if (self.table.dragging == NO && self.table.decelerating == NO)
{
[self startIconDownload:feedRecord forIndexPath:indexPath];
}
cell.imageView.image = [UIImage imageNamed:@"Placeholder.png"];
}
return cell;
}
- (void)startIconDownload:(FeedRecord *)feedRecord forIndexPath:(NSIndexPath *)indexPath
{
IconDownloader *iconDownloader = [imageDownloadsInProgress objectForKey:indexPath];
if (iconDownloader == nil)
{
iconDownloader = [[IconDownloader alloc] init];
iconDownloader.feedRecord = feedRecord;
iconDownloader.indexPathInTableView = indexPath;
iconDownloader.delegate = self;
[imageDownloadsInProgress setObject:iconDownloader forKey:indexPath];
[iconDownloader startDownload];
[iconDownloader release];
}
}
IconDownload.m
#import "IconDownloader.h"
#import "FeedRecord.h"
#define kAppIconHeight 48
@implementation IconDownloader
@synthesize feedRecord;
@synthesize indexPathInTableView;
@synthesize delegate;
@synthesize activeDownload;
@synthesize imageConnection;
#pragma mark
- (void)dealloc
{
[feedRecord release];
[indexPathInTableView release];
[activeDownload release];
[imageConnection cancel];
[imageConnection release];
[super dealloc];
}
- (void)startDownload
{
NSLog(@"%@ %@",@"Started downloading", feedRecord.profilePicture); // this shows in log
self.activeDownload = [NSMutableData data];
// alloc+init and start an NSURLConnection; release on completion/failure
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:
[NSURLRequest requestWithURL:
[NSURL URLWithString:feedRecord.profilePicture]] delegate:self];
self.imageConnection = conn;
NSLog(@"%@",conn); // this shows in log
[conn release];
}
- (void)cancelDownload
{
[self.imageConnection cancel];
self.imageConnection = nil;
self.activeDownload = nil;
}
#pragma mark -
#pragma mark Download support (NSURLConnectionDelegate)
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
NSLog(@"%@ %@",@"Got data for", feedRecord.profilePicture);
[self.activeDownload appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"%@",@"Fail!");
// Clear the activeDownload property to allow later attempts
self.activeDownload = nil;
// Release the connection now that it's finished
self.imageConnection = nil;
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(@"%@ %@",@"Done", feedRecord.profilePicture);
// Set appIcon and clear temporary data/image
UIImage *image = [[UIImage alloc] initWithData:self.activeDownload];
self.feedRecord.image = image;
self.activeDownload = nil;
[image release];
// Release the connection now that it's finished
self.imageConnection = nil;
NSLog(@"%@ %@",@"Our delegate is",delegate);
// call our delegate and tell it that our icon is ready for display
[delegate feedImageDidLoad:self.indexPathInTableView];
}
@end
Has anyone else experienced anything like this or can identify an issue with my code? Thanks!
