iPhone:与NSURL请求异步下载数据,而不是[NSData datawithContents ofURL] [英] iPhone: Downloading data asynchronously with NSURL request as opposed to [NSData datawithContents ofURL]
问题描述
我是新手,我试图从googleapi网页下载地理编码数据。我用它做了:代码:
Hi Im a newbie and Im trying to download geocoding data from googleapi webpage. I did it using this: code:
NSMutableString *urlStr = [[NSMutableString alloc] initWithString:temp];
NSMutableString *address = [[NSMutableString alloc] initWithString:l.Address];
[address appendString:@" "];
[address appendString:l.CityName];
[address appendString:@" "];
[address appendString:l.State];
[address appendString:@" "];
[address appendString:l.PostalCode];
NSArray *addressArray = [address componentsSeparatedByString:@" "];
[address release];
NSString *a = [addressArray componentsJoinedByString:@"+"];
[urlStr appendString:a];
[urlStr appendString:@"&sensor=false"];
NSURL *url = [[NSURL alloc] initWithString:[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSData *data = [NSData dataWithContentsOfURL:url];
它工作正常,但故障是它锁定了我的GUI,因为它全部是同步完成的。
It worked fine but the glitch was that it locked up my GUI since it was all done synchronously.
有人建议我使用NSURLrequest异步进行。所以我去了苹果网站。从那里我看到了他们的榜样。但是,我仍然坚持。如何将上述同步请求代码转换为异步请求?到目前为止,这就是我所拥有的,但我不确定这是否有效......有点困惑......有人可以用这个代码向我指出方向吗?
Someone suggested I do it asynchronously using NSURLrequest. So I went to the apple website. from there I saw their example. However, Im still stuck. How do I convert the above code which is a synchronous request to an asynchronous one? So far this is what I have, but Im not sure if this works...... a bit confused ... could someone please point me in the righ direction with this code?
NSURL *url = [[NSURL alloc] initWithString:[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
//create NSURL request for asynchronous processing
NSURLRequest *theRequest = [NSURLRequest requestWithURL:url
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];
NSURLConnection *theConnection= [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection)
{
receivedData = [[NSMutableData data] retain];
}
else
{
// Inform the user that the connection failed.
}
推荐答案
根据您构建代码的方式,您需要在成功完成后执行或通知其他对象(委托,通知) (connectionDidFinishLoading :)或失败(connection:didFailWithError :)。
Depending on how you structure your code, you'll want to act or notify some other object (delegate, notification) on successful completion (connectionDidFinishLoading:) or failure (connection: didFailWithError:).
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