如何将NSDictionary转换为NSData，反之亦然？

我正在发送NSString和UIImage使用蓝牙。我决定将两者都存储在中NSDictionary，然后将字典转换为NSData。

我的问题是如何转换NSDictionary成NSData签证，反之亦然？

NSDictionary-> NSData：

NSData *myData = [NSKeyedArchiver archivedDataWithRootObject:myDictionary];

NSData-> NSDictionary：

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

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 *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。

资源

使用NSJSONSerialization：

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

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

最新的return id，所以在转换后检查返回的对象类型是一个好主意（这里我转换为NSDictionary）。

在Swift 2中，您可以通过以下方式进行操作：

var dictionary: NSDictionary = ...

/* NSDictionary to NSData */
let data = NSKeyedArchiver.archivedDataWithRootObject(dictionary)

/* NSData to NSDictionary */
let unarchivedDictionary = NSKeyedUnarchiver.unarchiveObjectWithData(data!) as! NSDictionary

在Swift 3中：

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

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

来自NSData的NSDictionary

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

NSDictionary转换为NSData

您可以为此使用NSPropertyListSerialization类。看一下它的方法：

+ (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。

请试试这个

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