如何序列化NSDictionary / NSArray /属性列表（plist）包含NSNull [英] How to serialize a NSDictionary/NSArray/Property List (plist) which contains NSNull

问题描述

我想使用 NSNull 在 NSMutableDictionary 中存储一些空值，然后使用属性列表。问题是 NSNull 是不允许的，我得到属性列表是无效的格式的错误。有这个解决方法吗？看起来很奇怪，他们没有把 NSNull 放在有效的plist对象列表中。

I want to store in a NSMutableDictionary some null values using NSNull and then serialize this data using a property list. Problem is NSNull is not allowed and I get "Property list is in invalid format" error. Is there a workaround for this? Seems very surprising they didn't put NSNull on the list of valid plist objects.

推荐答案

在序列化之前，将NSArray或NSDictionary转换为NSData。以下是nsarray上用于序列化和反序列化的类别。这个舒适的处理一些数据是nsnull

I convert NSArray or NSDictionary to NSData before serializing. Following is a category on nsarray for serializing and deserializing. This comfortableby handles some data being nsnull

@implementation NSArray(Plist)

-(BOOL)writeToPlistFile:(NSString*)filename{
    NSData * data = [NSKeyedArchiver archivedDataWithRootObject:self];
    NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString * documentsDirectory = [paths objectAtIndex:0];
    NSString * path = [documentsDirectory stringByAppendingPathComponent:filename];
    BOOL didWriteSuccessfull = [data writeToFile:path atomically:YES];
    return didWriteSuccessfull;
}

+(NSArray*)readFromPlistFile:(NSString*)filename{
    NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString * documentsDirectory = [paths objectAtIndex:0];
    NSString * path = [documentsDirectory stringByAppendingPathComponent:filename];
    NSData * data = [NSData dataWithContentsOfFile:path];
    return  [NSKeyedUnarchiver unarchiveObjectWithData:data];
}

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