iphone - 'NSString' 没有可见的@interface 声明选择器 'appendData'

Question

就目前而言，这个问题不适合我们的问答形式。我们希望答案得到事实、引用资料或专业知识的支持，但这个问题可能会引发辩论、争论、投票或扩展讨论。如果您觉得这个问题可以改进并可能重新打开，visit the help center寻求指导。




9年前关闭。




我正在尝试异步调用服务器(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);
}

但我在从服务器获取内容时遇到问题:-
在 didReceiveData 函数中，出现以下错误:-
“NSString”没有可见的@interface 声明选择器“appendData”

有人可以建议我哪里错了吗？

Answer 1

在接口(interface)部分的 .h 文件中，请声明以下内容

NSMutableData *content;