Question

我遇到了NSKeyedArchiver的问题。我正在尝试存档一个字典，而字典又包含自定义对象数组，Album和Song。

专辑和歌曲都是NSObject固有的并且符合NSCoding协议。以下是我实施协议的方法：

相册实施文件：

-(id)initWithCoder:(NSCoder *)aDecoder {
    self = [super init];

    self.title = [aDecoder decodeObjectForKey:@"title"];
    self.artistName = [aDecoder decodeObjectForKey:@"artistName"];
    self.songs = [aDecoder decodeObjectForKey:@"songs"];

    return self;
}

-(void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeObject:self.title forKey:@"title"];
    [aCoder encodeObject:self.artistName forKey:@"artistName"];
    [aCoder encodeObject:self.songs forKey:@"songs"];
}

歌曲实施档案：

-(id)initWithCoder:(NSCoder *)aDecoder {
    self = [super init];
    self.title = [aDecoder decodeObjectForKey:@"title"];
    self.artistName = [aDecoder decodeObjectForKey:@"artistName"];

    return self;
}

-(void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeObject:self.title forKey:@"title"];
    [aCoder encodeObject:self.artistName forKey:@"artistName"];
}

title和artistName属性都是NSStrings，白色歌曲属性是Song对象的数组。

我将这些对象的数组放入一个名为ipodDictForArchiving的字典中，然后像这样归档字典：

-(NSData *)dataForClient {
    NSMutableData *data = [[NSMutableData alloc] init];
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    [archiver encodeObject:[self ipodDictForArchiving] forKey:kDataArchive];
    [archiver finishEncoding];
    NSLog(@"encoded dictionary");
    return data;
}

然后我将这样的字典解压缩：

-(NSDictionary *)unarchiveData:(NSData *)data {
    NSData *clientData = data;
    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:clientData];
    NSDictionary *myDictionary = [unarchiver decodeObjectForKey:kDataArchive];
    [unarchiver finishDecoding];

    return myDictionary;
}

由于某种原因，字典包含Song和Album对象，但这些对象的属性返回null。我无法想出任何帮助，非常感谢!!

由于

Answer 1

实现initWithCoder的方式不正确，如下所示：

- (id)initWithCoder:(NSCoder *)aDecoder {

    Album *al = [[Album alloc] init];

    al.title = [[[NSString alloc] initWithString:[aDecoder decodeObjectForKey:@"title"]] autorelease];
    al.artistName = [[[NSString alloc] init] initWithString:[aDecoder decodeObjectForKey:@"artistName"]] autorelease];
    al.songs = [[[NSArray alloc] initWithArray:[aDecoder decodeObjectForKey:@"songs"]] autorelease];

    return al;
}

同样的歌曲。

[编辑] 存档相册的方式似乎不正确，让我们尝试一种更简单的方法：

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:album];

然后您可以保存此数据以便以后取消归档。

NSKeyedArchiver未保存自定义对象属性

1 个答案: