我有一个php Web服务使用NSJSONSerialization将JSON返回到客观的iphone应用程序。我手动调用了Web服务并确认json有效，但是它已经返回了
The operation couldn’t be completed. (Cocoa error 3840.)
除此之外，它有时会起作用，有时却不起作用。时间不起作用的方法
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
实际上被调用了两次。 php web服务代码是：
$cu = new CacheUtil(getGlobalSetting("category_cache_file_name"));
$cu -> keyValue = FALSE;
$cu -> log = $log;
$categories = $cu -> getCache();
foreach ($categories as $key => $value) {
//TODO: make this category handling better. should array of arrays returned
array_push($tmp, $value -> id);
array_push($tmp, $value -> category);
array_push($tmp, $value -> parentCategory);
array_push($tmp, $value -> count);
array_push($tmp, $value -> itemCount);
array_push($return, $tmp);
$tmp = array();
}
} catch (Exception $e) {
$error = "TRUE";
$error_desc = $e -> getMessage();
$log -> lwrite($e -> getMessage());
}
sendResponse(200, json_encode(array("error" => $error, "error_desc" => $error_desc, "categories" => $return)));
return TRUE;
这会返回相当大的结果集，其截断版本如下：
{"error":"FALSE","error_desc":"","categories":[["1","All Categories","0","0","7"],["2","Antiques","0","20","0"],["3","Architectural, Garden","2","0","0"],["4","Art Deco (1925 - 1940)","2","0","0"],["5","Art Nouveau","2","0","0"],["6","Art","2","0","0"],["7","Asian Antiques","2","34","0"],["8","Amulets","7","0","0"],["9","Baskets","7","0","0"],["10","Bells","7","0","0"],["11","Bowls","7","0","0"],["12","Boxes","7","0","0"],["13","Bracelets","7","0","0"],["14","Brush Pots","7","0","0"],["15","Brush Washers","7","0","0"],["16","Cabinets","7","0","0"],["17","Chairs","7","0","0"],["18","Chests","7","0","0"],["19","Cups, Mugs","7","0","0"],["20","Fans","7","0","0"],["21","Glasses","7","0","0"],["22","Incense Burners","7","0","0"],["23","Kimonos","7","0","0"],["24","Masks","7","0","0"],["25","Military","7","0","0"],["26","Necklaces, Pendants","7","0","0"],["27","Other Asian","7","0","0"],["28","Paintings","7","0","0"],["29","Plates","7","0","0"],["30","Pots","7","0","0"],["31","Rings","7","0","0"],["32","Scrolls","7","0","0"],["33","Seals","7","0","0"],["34","Snuff Bottles","7","0","0"],["35","Statues","7","0","0"],["36","Swords","7","0","0"],["37","Tables","7","0","0"],["38","Tea Caddies","7","0","0"],["39","Teapots","7","0","0"],["40","Tsuba","7","0","0"],["41","Vases","7","0","0"],["42","Books, Publications","2","0","0"],["43","Decorative Arts","2","26","0"],["44","Bowls","43","0","0"],["45","Brass","43","0","0"],["46","Bronze","43","0","0"],["47","Cast Iron","43","0","0"],["48","Ceramics, Porcelain","43","0","0"],["49","Clocks","43","0","0"],["50","Copper","43","0","0"],["51","Cups, Saucers","43","0","0"],["52","Figurines","43","0","0"],["53","Glass","43","0","0"],["54","Gold","43","0","0"],["55","Jars","43","0","0"],["56","Jugs","43","0","0"],["57","Kitchen Tools","43","0","0"],["58","Lamps","43","0","0"],["59","Mirrors","43","0","0"],["60","Other Ceramics","43","0","0"],["61","Other Decorative Arts","43","0","0"],["62","Other Metalware","43","0","0"],["63","Pitchers","43","0","0"],["64","Plates, Platters","43","0","0"],["65","Teapots, Sets","43","0","0"],["66","Tin","43","0","0"],["67","Vases","43","0","0"],["68","Woodenware","43","0","0"],["69","Wrought Iron","43","0","0"],["70","Decor","2","0","0"],["71","Furniture","2","9","0"],["72","Beds","71","0","0"],["73","Cabinets, Cupboards","71","0","0"],["74","Chairs","71","0","0"],["75","Desks","71","0","0"],["76","Dining","71","0","0"],["77","Other Furniture","71","0","0"],["78","Sofas, Chaises","71","0","0"],["79","Stands","71","0","0"],["80","Tables","71","0","0"],["81","Maps, Atlases, Globes","2","0","0"],["82","Maritime","2","0","0"],["83","Musical Instruments","2","0","0"],["84","Other Antiques","2","0","0"],["85","Other Art Deco","2","0","0"],["86","Restoration and Care","2","0","0"],["87","Rugs, Carpets","2","0","0"],["88","Science, Medicine","2","0","0"],["89","Silver","2","0","0"],["90","Statues","2","0","0"],["91","Textiles, Linens","2","0","0"],["92","Art","0","13","0"],["93","Aboriginal Art","92","0","0"],["94","Art Cards, ACEO","92","0","0"],["95","Drawings","92","0","0"],["96","Fabric Art","92","0","0"],["97","Folk Art","92","0","0"],["98","Mixed Media, Collage","92","0","0"],["99","Other Art","92","0","0"],["100","Paintings","92","0","0"],["101","Photographs","92","0","0"],["102","Posters","92","0","0"],["103","Prints","92","0","0"],["104","Sculptures","92","0","0"],["105","Self-Representing Artists","92","0","0"],["106","Baby","0","19","0"],["107","Baby Clothing","106","12","0"],["108","Bottoms","107","0","0"],["109","Hair Accessories","107","0","0"],["110","Hats","107","0","0"],["111","....
客观方法是：
#pragma NSURLCONNECTION
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
//**Getting called twice
NSLog(@"Data output");
NSLog(@"%@", [NSString stringWithFormat:@"%@", [NSString stringWithUTF8String:[data bytes]]]);
MCUtility * util = [MCUtility alloc];
//Extract basic json
NSDictionary * dictionary = [util parseJson:data];
....
}
- (NSMutableDictionary *)parseJson : (NSData *) json
{
NSError *error;
NSMutableDictionary *dictionary = [NSJSONSerialization
JSONObjectWithData:json
options:NSJSONReadingMutableContainers
error:&error]; //** error here!!
if( error )
{
NSLog(@"parseJson");
NSLog(@"%@", [error localizedDescription]);
return nil;
}
return dictionary;
}
这让我很困惑，特别是因为它偶尔会起作用。 如果它有助于web服务当前位于http://mycobber-dev-msimcox-aaasrdivrh.elasticbeanstalk.com/webservice/iCategories.php以获得完整输出。
我在以下网站http://json.parser.online.fr/成功验证了它。
修改 感谢Wain指针。一旦出现进一步的问题（新手警报）
我已经宣布了实例变量
@implementation MCCategoryTableViewController
{
NSMutableData *receivedData;
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
NSLog(@"Data Received");
NSLog(@"%@", [NSString stringWithFormat:@"%@", [NSString stringWithUTF8String:[data bytes]]]);
[receivedData appendData:data];
}
最后完成
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(@"Retrieved all data");
NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]);
// NSLog(@"%@", [NSString stringWithFormat:@"%@", [NSString stringWithUTF8String: [receivedData bytes]]]);
[self populateCategoryPageOne:receivedData];
if ( connection != nil ) {
connection = nil;
receivedData = nil;
}
}
然而收到的数据是零？我在这里错过了一些基本的东西，有人可以建议
答案 0 :(得分：1)
您应该多次调用connection:didReceiveData:。每次调用它时，都应将新数据附加到作为属性保存的可变数据实例中。然后，当connectionDidFinishLoading:使用该可变数据实例反序列化整个响应时。
您当前的代码会尝试处理当前的部分回复，因此格式无效。