iPhone快速参考：http下载图片示例
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@property?(nonatomic,?retain) NSString *imageURLString;
@property (nonatomic, retain) NSMutableData *activeDownload;
@property (nonatomic, retain) NSURLConnection *imageConnection;
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- (void)startDownload;
- (void)cancelDownload;
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@end
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IconDownloader.m
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#import "IconDownloader.h"
@implementation IconDownloader
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@synthesize activeDownload;
@synthesize imageConnection;
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#pragma mark
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- (void)dealloc
{
? ? [activeDownload release];
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? ? [imageConnection cancel];
? ? [imageConnection release];
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? ? [super dealloc];
}
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- (void)startDownload
{
? ? self.activeDownload = [NSMutableData data];
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? ? // alloc+init and start an NSURLConnection; release on completion/failure
? ? NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:
?? ? ? ? ? ? ? ? ? ? ? ? ? ? [NSURLRequest requestWithURL:
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? [NSURL URLWithString:imageURLString]] delegate:self];
? ? self.imageConnection = conn;
? ? [conn release];
}
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- (void)cancelDownload
{
? ? [self.imageConnection cancel];
? ? self.imageConnection = nil;
? ? self.activeDownload = nil;
}
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#pragma mark -
#pragma mark Download support (NSURLConnectionDelegate)
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- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
? ? [self.activeDownload appendData:data];
}
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- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
// Clear the activeDownload property to allow later attempts
? ? self.activeDownload = nil;
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? ? // Release the connection now that it's finished
? ? self.imageConnection = nil;
}
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- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
? ? // Set appIcon and clear temporary data/image
? ? UIImage *image = [[UIImage alloc] initWithData:self.activeDownload];
? ? self.activeDownload = nil;
? ? [image release];
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? ? // Release the connection now that it's finished
? ? self.imageConnection = nil;
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}
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@end