我搜索并尝试了许多不同的解决方案，但都没有成功。

我正在尝试向我的服务器发出 JSON 请求，它确实有效，因为我已经在 PHP 中对其进行了测试(简单的调用，它接收字符串名称和字符串密码，如果用户正确则检查数据库)。该请求应该只收到带有属性“success”(可以是“true”或“false”)的 JSON。

这是我的代码:

- (void)logonService:(NSString *) name widthArg2:(NSString *) password {
// Create the request.
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://46.51.169.145/ios/index.php/user/login/"]];

// Specify that it will be a POST request
request.HTTPMethod = @"POST";

//setting json fields
[request setValue:@"application/json; charset=utf-8" forHTTPHeaderField:@"Content-Type"];

//prepare output data
NSString *in1;
NSDictionary *outputData = [NSDictionary dictionaryWithObjectsAndKeys:in1, @"success", nil];
NSError *error = nil;
NSData *jsonOutputData = [NSJSONSerialization dataWithJSONObject:outputData options:NSJSONWritingPrettyPrinted error:&error];
NSString *jsonOutputString = [[NSString alloc] initWithData:jsonOutputData encoding:NSUTF8StringEncoding];
//set json string to body data
NSData *requestInputBodyData = [jsonOutputString dataUsingEncoding:NSUTF8StringEncoding];
[request setHTTPBody: requestInputBodyData];

//prepare input data
NSString *input = [NSString stringWithFormat:@"&name=%@&password=%@",name,password];
//Encode the post string using NSASCIIStringEncoding and also the post string you need to send in NSData format.
NSData *inputData = [input dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
//calculate length of post data
NSString *inputLength = [NSString stringWithFormat:@"%d",[inputData length]];
//Set HTTP header field with length of the post data.
[request setValue:inputLength forHTTPHeaderField:@"Content-Length"];
//encode type
//[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Current-Type"];
//add it to http body
[request setHTTPBody:inputData];

// Create url connection and fire request
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
if(conn){
    NSLog(@"Connection Successful");
}else{
    NSLog(@"Connection could not be made");
}

委托(delegate) DidReceiveData 正确触发但结果始终为 NIL:

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
NSString *jsonResponseData = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
NSLog(@"RESULT1: %@", jsonResponseData);
[_responseData appendData:data];

谢谢，希望有人能帮助我!

最佳答案

非常感谢您的评论，我终于修复了它，之后我决定开始使用 JSON 库 --> https://github.com/stig/json-framework/

这就是我最终得到代码的方式:

//prepare connection
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@user.php", _urlServer]];
NSMutableDictionary *data = [[NSMutableDictionary alloc] init];
[data setObject:@"login" forKey:@"action"];
[data setObject:username forKey:@"username"];
[data setObject:password forKey:@"password"];

//start connection
// Create the request, if there is a connection going on just cancel it.
[_connection cancel];

//initialize new mutable data
NSMutableData *receivedData = [[NSMutableData alloc] init];
_receivedData = receivedData;

//initialize the url which will be fetched
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[url standardizedURL]];

//set http method
[request setHTTPMethod:@"POST"];

//initialize a post data
NSString *dataString = [[NSString alloc] init];
for(id key in data) {
    id value = [data objectForKey:key];
    //keys string
    NSString *newData =  [NSString stringWithFormat:@"&%@=%@", key, value];
    dataString = [dataString stringByAppendingString: newData];
}

//set request content type we MUST set this value.
[request setValue:@"application/x-www-form-urlencoded;charset=UTF-8" forHTTPHeaderField:@"Content-Type"];

//set post data of request
[request setHTTPBody:[dataString dataUsingEncoding:NSUTF8StringEncoding]];

//initialize a connection from request
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
_connection = connection;

//NSLog(@"Sending request with parameters: %@", dataString);

//begin the connection
[_connection start];

它的工作就像一个魅力。下一步是以某种方式进行身份验证，现在连接已向世界开放。

关于ios - 尝试在 Objective-C (IOS7) 中做一个简单的 JSON 请求，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19097099/