我想打电话给服务器异步（ARC -on）：
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:request delegate:self];
if (theConnection) {
content = [NSMutableData data];
NSLog(@"responseData from setup.php: %@", content);
} else {
// Inform the user that the connection failed.
NSLog(@"error from server response in set up");
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
NSLog(@"connection did receive response");
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[content appendData:data];
NSLog(@"connection did receive data");
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(@"connection did finish load");
NSLog(@"Succeeded! Received %@ bytes of data",receivedData);
}
但我有问题，从服务器获取内容： - 在didReceiveData功能，下面的错误来了： - 为“NSString的”不可见@interface声明选择“appendData”
任何人都可以给我建议，我可能是错的？
