Iphone 如何在Objective-C中实现事件驱动算法,类似于NSXMLParser
我想实现一个classX,它可以进行一些异步调用,但是在调用方ClassC看来,classX应该是顺序的 ClassC将实例化ClassX,它通过NSURLConnection进行一些HTTP调用,因此,它变得异步(我希望它保持异步) 逻辑如下: C类:Iphone 如何在Objective-C中实现事件驱动算法,类似于NSXMLParser,iphone,objective-c,Iphone,Objective C,我想实现一个classX,它可以进行一些异步调用,但是在调用方ClassC看来,classX应该是顺序的 ClassC将实例化ClassX,它通过NSURLConnection进行一些HTTP调用,因此,它变得异步(我希望它保持异步) 逻辑如下: C类: - (void)callerWork { // shouldn't return until connection response completes // and receives all of the response
- (void)callerWork
{
// shouldn't return until connection response completes
// and receives all of the response data
BOOL result = [classX doSomeWork];
}
类别X:
- (void)doSomeWork
{
// With an NSURLRequest, initiates a NSURLConnection
// Only after all of the data is received (or error) from
// NSURLConnection via NSURLConnectionDelegate methods,
// return from this method
}
// Implements relevant NSURLConnectionDelegate methods
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{ }
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{ }
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{ }
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{ }
@end
基本上,我想模拟NSXMLParser的工作方式,调用它的“parse”方法,直到所有工作完成后才返回。为了处理数据,NSXMLParser将调用由调用类实现的相关NSXMLParserDelegate方法,如下所示:
- (void)parseWork
NSXMLParser *parser = [[NSXMLParser alloc] initWithData:dataToParse];
[parser setDelegate:self];
// 'parse' method doesn't return right away - execution continues
// only after all of the data has been parsed, which means the delegate
// methods are getting called in the interim.
BOOL parseResult = [parser parse];
}
做这件事的好方法是什么
我知道您需要让一个类作为另一个类的代理来进行回调
但是,您使用什么机制使“[parser parse]”不会立即返回?您可以启动另一个线程来完成所有异步工作,并自行休眠,直到工作线程在完成时将其唤醒。但是,不要从主线程调用此方法,因为您不想在主UI线程中休眠。新的运行循环仍必须位于classX方法调用之外的另一个线程中。