performSelectorOnMainThread 和detachNewThreadSelector区别.
举例说明怎么简单的创建一个子线程。用到的类是NSThread类，这里使用detachNewTheadSelector:toTagaet:withObject创建一个线程。函数setupThread:(NSArray*)userInfor。通过userInfor将需要的数据传到线程中。函数定义：-(void)setupThread:(NSArray*)userInfor{ [NSThread detachNewThreadSelector:@selector(threadFunc:) toTarget:self withObject:(id)userInfor];}- (void)threadFunc:(id)userInfor{ NSAutoreleasePool*pool = [[NSAutoreleasePool alloc] init]; //。。。。需要做的处理。 //这里线程结束后立即返回 [self performSelectorOnMainThread:@selector(endThread) withObject:nil waitUntilDone:NO]; [pool release];}performSelectorOnMainThread通知主线程执行函数endThread。也可以使用performSelector:onThread:withObject:waitUntil 通知某线程执行线程结束后的处理。线程内不要刷新界面。如果需要刷新界面，通过performSelectorOnMainThread，调出主线程中的方法去刷新。 例如，启动一个线程下载图片：//启动线程[NSThread detachNewThreadSelector:@selector(downloadImage:) toTarget:self withObject:url];//线程函数- (void) downloadImage:(NSString*)url{ _subThreed = [NSThread currentThread]; self.uploadPool = [[NSAutoreleasePool alloc] init]; self.characterBuffer = [NSMutableData data]; done = NO; [[NSURLCache sharedURLCache] removeAllCachedResponses]; NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:[NSURLURLWithString:url]]; self.connection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; [self performSelectorOnMainThread:@selector(httpConnectStart) withObject:nil waitUntilDone:NO]; if (connection != nil) { do { [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]]; } while (!done); } self.photo = [UIImage imageWithData:characterBuffer]; //下载结束，刷新 [self performSelectorOnMainThread:@selector(fillPhoto) withObject:nil waitUntilDone:NO]; // Release resources used only in this thread. self.connection = nil; [uploadPool release]; self.uploadPool = nil; _subThreed = nil;}#pragma mark NSURLConnection Delegate methods/* Disable caching so that each time we run this app we are starting with a clean slate. You may not want to do this in your application. */- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse { return nil;}// Forward errors to the delegate.- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { done = YES; [self performSelectorOnMainThread:@selector(httpConnectEnd) withObject:nil waitUntilDone:NO]; [characterBuffer setLength:0]; }// Called when a chunk of data has been downloaded.- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { // Process the downloaded chunk of data. [characterBuffer appendData:data]; }- (void)connectionDidFinishLoading:(NSURLConnection *)connection { [self performSelectorOnMainThread:@selector(httpConnectEnd) withObject:nil waitUntilDone:NO]; // Set the condition which ends the run loop. done = YES; }