[英]How can I convert NSDictionary to NSData and vice versa?
I am sending NSString
and UIImage
using bluetooth. 我正在使用蓝牙发送
NSString
和UIImage
。 I decided to store both in a NSDictionary
and then convert the dictionary to NSData
. 我决定将它们存储在
NSDictionary
,然后将字典转换为NSData
。
My question is how to convert NSDictionary
to NSData
and visa versa? 我的问题是如何将
NSDictionary
转换为NSData
,反之亦然?
NSDictionary -> NSData: NSDictionary - > NSData:
NSData *myData = [NSKeyedArchiver archivedDataWithRootObject:myDictionary];
NSData -> NSDictionary: NSData - > NSDictionary:
NSDictionary *myDictionary = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:myData];
NSDictionary -> NSData: NSDictionary - > NSData:
NSMutableData *data = [[NSMutableData alloc] init];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
[archiver encodeObject:yourDictionary forKey:@"Some Key Value"];
[archiver finishEncoding];
[archiver release];
// Here, data holds the serialized version of your dictionary
// do what you need to do with it before you:
[data release];
NSData -> NSDictionary NSData - > NSDictionary
NSData *data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
NSDictionary *myDictionary = [[unarchiver decodeObjectForKey:@"Some Key Value"] retain];
[unarchiver finishDecoding];
[unarchiver release];
[data release];
You can do that with any class that conforms to NSCoding. 您可以使用符合NSCoding的任何类来执行此操作。
Use NSJSONSerialization: 使用NSJSONSerialization:
NSDictionary *dict;
NSData *dataFromDict = [NSJSONSerialization dataWithJSONObject:dict
options:NSJSONWritingPrettyPrinted
error:&error];
NSDictionary *dictFromData = [NSJSONSerialization JSONObjectWithData:dataFromDict
options:NSJSONReadingAllowFragments
error:&error];
The latest returns id
, so its a good idea to check the returned object type after you cast (here i casted to NSDictionary). 最新的返回
id
,因此在转换后检查返回的对象类型是个好主意(这里我是转换为NSDictionary)。
In Swift 2 you can do it in this way: 在Swift 2中,你可以这样做:
var dictionary: NSDictionary = ...
/* NSDictionary to NSData */
let data = NSKeyedArchiver.archivedDataWithRootObject(dictionary)
/* NSData to NSDictionary */
let unarchivedDictionary = NSKeyedUnarchiver.unarchiveObjectWithData(data!) as! NSDictionary
In Swift 3 : 在Swift 3中 :
/* NSDictionary to NSData */
let data = NSKeyedArchiver.archivedData(withRootObject: dictionary)
/* NSData to NSDictionary */
let unarchivedDictionary = NSKeyedUnarchiver.unarchiveObject(with: data)
NSDictionary from NSData 来自NSData的NSDictionary
http://www.cocoanetics.com/2009/09/nsdictionary-from-nsdata/ http://www.cocoanetics.com/2009/09/nsdictionary-from-nsdata/
NSDictionary to NSData NSDictionary到NSData
You can use NSPropertyListSerialization class for that. 您可以使用NSPropertyListSerialization类。 Have a look at its method:
看看它的方法:
+ (NSData *)dataFromPropertyList:(id)plist format:(NSPropertyListFormat)format
errorDescription:(NSString **)errorString
Returns an NSData object containing a given property list in a specified format. 返回包含指定格式的给定属性列表的NSData对象。
Please try this one 请试试这个
NSError *error;
NSDictionary *responseJson = [NSJSONSerialization JSONObjectWithData:webData
options:NSJSONReadingMutableContainers
error:&error];
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