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;?
}
