NSDictionary with ordered keys
The solution of having an associated NSMutableArray of keys isn’t so bad. It avoids subclassing NSDictionary, and if you are careful with writing accessors, it shouldn’t be too hard to keep synchronised.
nsdictionary
Converting NSString to NSDictionary / JSON
I believe you are misinterpreting the JSON format for key values. You should store your string as NSString *jsonString = @”{\”ID\”:{\”Content\”:268,\”type\”:\”text\”},\”ContractTemplateID\”:{\”Content\”:65,\”type\”:\”text\”}}”; NSData *data = [jsonString dataUsingEncoding:NSUTF8StringEncoding]; id json = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil]; Now if you do following NSLog statement NSLog(@”%@”,[json objectForKey:@”ID”]); Result would be another NSDictionary. { Content = 268; type = text; }
Get all keys of an NSDictionary as an NSArray
Just use NSArray*keys=[dict allKeys]; In general, if you wonder if a specific class has a specific method, look up Apple’s own documentation. In this case, see NSDictionary class reference. Go through all the methods. You’ll discover many useful methods that way.
Appending NSDictionary to other NSDictionary
You looking for this guy: [NSMutableDictionary addEntriesFromDictionary:] Make sure your UITableView dictionary is an NSMutableDictionary! Check it here
Using NSPredicate to filter an NSArray based on NSDictionary keys
It should work – as long as the data variable is actually an array containing a dictionary with the key SPORT NSArray *data = [NSArray arrayWithObject:[NSMutableDictionary dictionaryWithObject:@”foo” forKey:@”BAR”]]; NSArray *filtered = [data filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@”(BAR == %@)”, @”foo”]]; Filtered in this case contains the dictionary. (the %@ does not have to be quoted, this is done … Read more
How to add to an NSDictionary
A mutable dictionary can be changed, i.e. you can add and remove objects. An immutable is fixed once it is created. create and add: NSMutableDictionary *dict = [[NSMutableDictionary alloc]initWithCapacity:10]; [dict setObject:[NSNumber numberWithInt:42] forKey:@”A cool number”]; and retrieve: int myNumber = [[dict objectForKey:@”A cool number”] intValue];
NSDictionary – Need to check whether dictionary contains key-value pair or not
Just ask it for the objectForKey:@”b”. If it returns nil, no object is set at that key. if ([xyz objectForKey:@”b”]) { NSLog(@”There’s an object set for key @\”b\”!”); } else { NSLog(@”No object set for key @\”b\””); } Edit: As to your edited second question, it’s simply NSUInteger mCount = [xyz count];. Both of these … Read more
How do I deserialize a JSON string into an NSDictionary? (For iOS 5+)
It looks like you are passing an NSString parameter where you should be passing an NSData parameter: NSError *jsonError; NSData *objectData = [@”{\”2\”:\”3\”}” dataUsingEncoding:NSUTF8StringEncoding]; NSDictionary *json = [NSJSONSerialization JSONObjectWithData:objectData options:NSJSONReadingMutableContainers error:&jsonError];
How to use NSJSONSerialization
Your root json object is not a dictionary but an array: [{“id”: “1”, “name”:”Aaa”}, {“id”: “2”, “name”:”Bbb”}] This might give you a clear picture of how to handle it: NSError *e = nil; NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: data options: NSJSONReadingMutableContainers error: &e]; if (!jsonArray) { NSLog(@”Error parsing JSON: %@”, e); } else { for(NSDictionary … Read more
How can I convert NSDictionary to NSData and vice versa?
NSDictionary -> NSData: NSData *myData = [NSKeyedArchiver archivedDataWithRootObject:myDictionary]; NSData -> NSDictionary: NSDictionary *myDictionary = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:myData];