Question

我正在尝试将一个简单的json feed元素分配给标签。我的json feed看起来像这样：

[{"code":501,"data":{"req":"0"}}]

我从网址检索后的代码：

 NSURLResponse *response;
 NSData *POSTReply = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
 NSString *theReply = [[NSString alloc] initWithBytes:[POSTReply bytes] length:[POSTReply length] encoding: NSASCIIStringEncoding];
 NSLog(@"Reply: %@", theReply);

 NSArray* json_object = [NSJSONSerialization
                       JSONObjectWithData:POSTReply
                       options:0
                       error:nil];
 NSArray *json_object_line = [json_object objectAtIndex:0];
 mainLabel.Text= [json_object_line valueForKey:@"code"];

我无法让这个工作。该应用程序只是崩溃，除非我删除最后2行。我尝试了很多其他选项（特别是最后两行）无济于事。

我有什么问题吗？

Answer 1

您尝试将NSNumber分配给标签的text媒体资源。这是崩溃的原因。正确的方法是从JSON字段获取格式化字符串：

 NSURLResponse *response;
 NSData *POSTReply = [NSURLConnection sendSynchronousRequest:request
                                           returningResponse:&response error:nil];
 NSString *theReply = [[NSString alloc] initWithBytes:POSTReply.bytes
                                               length:POSTReply.length
                                             encoding:NSASCIIStringEncoding];

 NSArray* json_object = [NSJSONSerialization JSONObjectWithData:POSTReply
                                                        options:0
                                                          error:nil];
 NSDictionary *json_object_line = json_object[0];
 mainLabel.text= [NSString stringWithFormat:@"%@", json_object_line[@"code"]];

将单行json元素分配给Objective-c中的标签

1 个答案: