如何发送asynchronousURL请求？
我想知道如何获得一个返回值1或0只是…从一个URL请求asynchronous返回。
目前我是这样做的：
NSString *UTCString = [NSString stringWithFormat:@"http://web.blah.net/question/CheckQuestions?utc=%0.f",[lastUTCDate timeIntervalSince1970]]; NSLog(@"UTC String %@",UTCString); NSURL *updateDataURL = [NSURL URLWithString:UTCString]; NSString *checkValue = [NSString stringWithContentsOfURL:updateDataURL encoding:NSASCIIStringEncoding error:Nil]; NSLog(@"check Value %@",checkValue); 这工作，但是它阻止我的主线程，直到我从URL的回复，我如何设置它，这样做会在另一个线程，而不是主线程？
编辑：答案我结束upcalling我的function，这个效果不错:)
[self performSelectorInBackground:@selector(shouldCheckForUpdate) withObject:nil];
你可以使用NSURLConnection类
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]]; [[[NSURLConnection alloc] initWithRequest:request delegate:self] autorelease];
并使用其委托方法处理其响应和错误。
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error - (void)connectionDidFinishLoading:(NSURLConnection *)connection
你可以findNSURLConnection的实现
- 苹果文档：使用NSURLConnection
- 如何通过示例使用iOS NSURLConnection
编辑：虽然NSURLConnection是由苹果提供更多的build议的方式放置URL请求。 但是，我发现AFNetworking库非常省时，易于实现，而且作为第三方实现也非常简单。 你应该试试看。
尝试这个 ：
。H：
NSMutableData *responseData;
.M：
- (void)load { NSURL *myURL = [NSURL URLWithString:@"http://www.example.com"]; NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myURL cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:60]; [[NSURLConnection alloc] initWithRequest:request delegate:self]; } - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { responseData = [[NSMutableData alloc] init]; } - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { [responseData appendData:data]; } - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { [responseData release]; [connection release]; [textView setString:@"Unable to fetch data"]; } - (void)connectionDidFinishLoading:(NSURLConnection *)connection { NSLog(@"Succeeded! Received %d bytes of data",[responseData length]); NSString *txt = [[[NSString alloc] initWithData:responseData encoding: NSASCIIStringEncoding] autorelease]; }
使用NSURLConnection并提出请求。 然后你可以用NSURLConnection的方法启动同步或asynchronous连接：
同步加载数据
+ sendSynchronousRequest:returningResponse:error:
asynchronous加载数据
+ connectionWithRequest:delegate: – initWithRequest:delegate: – initWithRequest:delegate:startImmediately: – start
检查Apple Developer API参考中的NSURLConnection类。
无耻地从https://gist.github.com/knmshk/3027474复制。; 所有学分转到https://gist.github.com/knmshk 。
xmlData = [[NSMutableData alloc] init]; NSURL *url = [NSURL URLWithString: @"http://forrums.bignerdranch.com/smartfeed.php?" @"limit=NO_LIMIT&count_limit20&sort_by=standard&" @"feed_type=RSS2.0&feed_style=COMPACT"]; NSURLRequest *request = [NSURLRequest requestWithURL:url]; //connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES]; NSOperationQueue *queue = [[NSOperationQueue alloc]init]; [NSURLConnection sendAsynchronousRequest:request queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){ if (error) { xmlData = nil; NSLog(@"error:%@", error.localizedDescription); } [xmlData appendData:data]; }];
iOS XCode文档中有一个名为LazyTableImages的示例。 在滚动停止之后，这将执行asynchronousURL以及asynchronous图像加载到屏幕上显示的UITableView单元格。 协议的优秀例子，asynchronous数据处理等
