Iphone json数据回复无

2011-02-11 12:01:16.653 mystack[1946:207]jsondata=，（空）

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您应该记录错误变量以查看发生的情况：

[error localizedDescription]

谢谢您的帮助，这是答案

NSString *urlString =[NSString stringWithFormat:@"http://api.stackoverflow.com/1.0/questions?tagged=iphone & key=%d",key1];
    NSURL *url = [NSURL URLWithString:urlString];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
    [request setHTTPMethod:@"POST"];
    [request setValue:@"text/json" forHTTPHeaderField:@"Content-Type"];
    [request setValue:@"text/json" forHTTPHeaderField:@"Accept"];

    NSError        *error ;
    NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:&error];
    NSString *json_string = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
    NSLog(@"jsondata=%@,%@",json_string,response);

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我必须更改的代码。

您的URL字符串无效，因为它包含空格：

&

。在创建

NSURL

对象之前，需要转义这些。替换：

[request setHTTPMethod:@"POST"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];

与：

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服务器的响应似乎有问题。我建议您这样记录响应的文件长度[response length]，以检查NSData实例是否为空。jsondata=，（null），0，Error Domain=NSURLErrorDomain Code=-1000“bad URL”UserInfo=0x4b65150{NSUnderlyingError=0x4b68fd0“bad URL”，NSLocalizedDescription=bad URL}

NSString *urlString =[NSString stringWithFormat:@"http://api.stackoverflow.com/1.0/questions?tagged=iphone & key=%d",key1];

NSString *urlString =[NSString stringWithFormat:@"http://api.stackoverflow.com/1.0/questions?tagged=iphone & key=%d",key1];
urlString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];