[英]iOS JSON Parse not working (returns null dictionary)
我使用NSJSONSerialization
的JSONObjectWithData:data options: error:
解析从服务器返回的JSON数据。
现在,对于options参数,我使用: NSJSONReadingAllowFragments
。 您可以在下面查看并查看实际的JSON(我认为问题出在哪里)。
我收到的错误消息是:
错误域= NSCocoaErrorDomain代码= 3840“操作无法完成。(可可错误3840。)”(字符0周围的无效值。)UserInfo = 0x6895da0 {NSDebugDescription =字符0周围的无效值。}
知道如何解决吗?
JSON =
{"name":"Johan Appleseed",
"email":"j.appleseed@emuze.co",
"phone":"+4121876003",
"accounts":{
"facebook":[true,1125],
"twitter":[false,null],
"homepage":[true,"http:\/\/johnAplleseed.com\/index.html"]}}
可能您有一些看不见的无法打印的角色。 尝试这个:
NSData *jsonData = ...
const unsigned char *ptr = [data bytes];
for(int i=0; i<[data length]; ++i) {
unsigned char c = *ptr++;
NSLog(@"char=%c hex=%x", c, c);
}
为了验证您在数据的开头或结尾处没有不可打印的字符。
编辑:澄清一下,只需在JSON字典上运行以上内容即可-解析失败的字典。
Ive明智地发现了问题所在,因为URL的返回是一个HTML页面,在实际响应周围附加了所有这些html,head和body标签,因此无法对其进行解析。 这是有关如何从响应中删除HTML标记(将其更改为字符串后)的很好的问答: 从iPhone上的NSString删除HTML标记
我有一段时间遇到同样的问题,我只是发现,如果我要从网页中提取数据(例如PHP页面),则该页面中不应有任何HTML标记。 像这样的结构:
<html>
<body>
<?php
?>
</body>
</html>
将破坏您的结果。 变成:
<?php
?>
为我工作。
已经有一段时间了,但是打印数据的一种更简单的方法是:
NSLog(@“%@”,[[NSString alloc] initWithData:data编码:NSUTF8StringEncoding]);
一种方法是,您可以通过发布请求解析jsondata
-(void)callWebserviceList
{
spinner.hidden=NO;
NSString *bodyData = @"code_request=monuments_list&asi_id=1";
NSMutableURLRequest *postRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://asicircles.com/server_sync.php"]];
// Set the request's content type to application/x-www-form-urlencoded
[postRequest setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
// Designate the request a POST request and specify its body data
[postRequest setHTTPMethod:@"POST"];
[postRequest setHTTPBody:[NSData dataWithBytes:[bodyData UTF8String] length:strlen([bodyData UTF8String])]];
connection1 = [NSURLConnection connectionWithRequest:postRequest委托人:self];
if(connection1 !=nil)
{
////NSLog(@"%@",postRequest);
}
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
if ([connection isEqual:connection1 ])
{
[responseData setLength:0];
}else if ([connection isEqual:connection2 ])
{
[responseData1 setLength:0];
}
}-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
if ([connection isEqual:connection1 ])
{
[responseData appendData:data];
}else if ([connection isEqual:connection2 ])
{
[responseData1 appendData:data];
}
//**check here for responseData & also data**
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"%@",[NSString stringWithFormat:@"Connection failed: %@", [error description]]);
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
if ([connection isEqual:connection1 ])
{
spinner.hidden=YES;
NSError *error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSMutableArray *arrdata=[json objectForKey:@"message"];
NSLog(@"code is%@", json);
for (int i=0; i< arrdata.count; i++)
{
[arrDetails addObject:[[arrdata objectAtIndex:i]objectForKey:@"details"]];
[arrImageUrl addObject:[[arrdata objectAtIndex:i]objectForKey:@"image"]];
[arrLat addObject:[[arrdata objectAtIndex:i]objectForKey:@"lat"]];
[arrLongi addObject:[[arrdata objectAtIndex:i]objectForKey:@"longi"]];
[arrName addObject:[[arrdata objectAtIndex:i]objectForKey:@"name"]];
[arrLoc addObject:[[arrdata objectAtIndex:i]objectForKey:@"location"]];
[arrID addObject:[[arrdata objectAtIndex:i]objectForKey:@"id"]];
NSLog(@"code is%@",[[arrdata objectAtIndex:i]objectForKey:@"details"]);
NSLog(@"code is%@",[arrImageUrl objectAtIndex:i]);
}
if (arrName.count > 0)
{
[self addscrollView];
}
}else if ([connection isEqual:connection2 ])
{
}
}
您还可以在iOS中按块访问json数据的url
#define kBgQueue dispatch_get_global_queue(
DISPATCH_QUEUE_PRIORITY_DEFAULT, 0) //1
#define kLatestKivaLoansURL [NSURL URLWithString:
@"http://api.kivaws.org/v1/loans/search.json?status=fundraising"] //2
我们需要做的第一件事是从Web下载JSON数据。 幸运的是,有了GCD,我们可以在一行代码中做到这一点! 将以下内容添加到ViewController.m中:
- (void)viewDidLoad
{
[super viewDidLoad];
dispatch_async(kBgQueue, ^{
NSData* data = [NSData dataWithContentsOfURL:
kLatestKivaLoansURL];
[self performSelectorOnMainThread:@selector(fetchedData:)
withObject:data waitUntilDone:YES];
});
}
- (void)fetchedData:(NSData *)responseData {
//parse out the json data
NSError* error;
NSDictionary* json = [NSJSONSerialization
JSONObjectWithData:responseData //1
options:kNilOptions
error:&error];
NSArray* latestLoans = [json objectForKey:@"loans"]; //2
NSLog(@"loans: %@", latestLoans); //3
}
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