NSCoding协议问题 [英] NSCoding protocol question

问题描述

我想将存档（NSCoding）协议添加到我的模型类中，然后实现两种方法 encodeWithCoder：（NSCoder *）coder 和 initWithCoder：（NSCoder *）coder 。 MyModelClass具有2个实例变量（NSString和NSImage），所以我使用 encodeObject：（id）object forKey：（NSString *）string 方法对对象加上值进行编码特定的键。但是我一直看到错误：

I want to add the archiving (NSCoding) protocol to my model class, and then i implement both methods encodeWithCoder:(NSCoder*)coder and initWithCoder:(NSCoder*)coder. MyModelClass has 2 instance variables (NSString and NSImage), so i use the encodeObject:(id)object forKey:(NSString*)string method to encode the object plus the value for particular key. But i keep got the error :

*** -encodeObject：forKey：仅为抽象类定义。定义-[NSArchiver encodeObject：forKey：]！

这是我的NSCoding方法代码：

here's my code for NSCoding methods :

- (id)initWithCoder:(NSCoder *)coder {
 [super init];
 mainPath = [[coder decodeObjectForKey:@"mainPath"] retain];
 icon = [[coder decodeObjectForKey:@"icon"] retain];

 return self;
}

- (void)encodeWithCoder:(NSCoder *)coder {
 NSLog(@"encode with coder is called");
 [coder encodeObject:mainPath forKey:@"mainPath"];
 [coder encodeObject:icon forKey:@"icon"];

}

这就是我在控制器类中称呼它们的方式：

And this is how i call them at my controller class :

id object = [assetArray objectAtIndex: [[rows lastObject] intValue]];

 if ([object isKindOfClass:[ItemAssetModel class]])
  NSLog(@"object is correct");
 else
  return NO;

 NSData *data = [NSArchiver archivedDataWithRootObject: object];

如果我更改 encodeObject：（id）obj forKey：（NSString * ）str 和 encodeObject：{id）obj ，错误停止，但结果是，归档数据未复制实例变量值（cmiiw）。我想念这个吗？

if i change the encodeObject:(id)obj forKey:(NSString*)str with encodeObject:(id)obj, the error is stops, but the result is, the archived data does not copy the instance variable value (cmiiw). Do i miss something on this?

谢谢。
hebbian

thanks. hebbian

推荐答案

尝试使用NSKeyedArchiver而不是NSArchiver。

Try using NSKeyedArchiver instead of NSArchiver.

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