如何将NSDictionary转换为NSData，反之亦然？

Question

我正在使用蓝牙发送NSString和UIImage。我决定将它们存储在NSDictionary中，然后将字典转换为NSData。

我的问题是如何将NSDictionary转换为NSData，反之亦然？

Answer 1

NSDictionary - ＆gt; NSData：

NSData *myData = [NSKeyedArchiver archivedDataWithRootObject:myDictionary];

NSData - ＆gt;的NSDictionary：

NSDictionary *myDictionary = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:myData];

Answer 2

NSDictionary - ＆gt; NSData的：

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 - ＆gt;的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];

您可以使用符合NSCoding的任何类来执行此操作。

source

Answer 3

使用NSJSONSerialization：

NSDictionary *dict;
NSData *dataFromDict = [NSJSONSerialization dataWithJSONObject:dict
                                                       options:NSJSONWritingPrettyPrinted
                                                         error:&error];

NSDictionary *dictFromData = [NSJSONSerialization JSONObjectWithData:dataFromDict
                                                             options:NSJSONReadingAllowFragments
                                                               error:&error];

最新返回id，因此最好在投射后检查返回的对象类型（这里是我转换为NSDictionary）。

Answer 4

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

在 Swift 3 ：

/* NSDictionary to NSData */
let data = NSKeyedArchiver.archivedData(withRootObject: dictionary)

/* NSData to NSDictionary */
let unarchivedDictionary = NSKeyedUnarchiver.unarchiveObject(with: data)

Answer 5

来自NSData的NSDictionary

http://www.cocoanetics.com/2009/09/nsdictionary-from-nsdata/

NSDictionary到NSData

您可以使用NSPropertyListSerialization类。看看它的方法：

+ (NSData *)dataFromPropertyList:(id)plist format:(NSPropertyListFormat)format
                              errorDescription:(NSString **)errorString

返回包含指定格式的给定属性列表的NSData对象。

Answer 6

请尝试这个

NSError *error;
NSDictionary *responseJson = [NSJSONSerialization JSONObjectWithData:webData
                                options:NSJSONReadingMutableContainers
                                error:&error];