无法将NSDictionary保存到文件中

Question

我认为标题说的都是.我使用了一些我在这里找到的示例代码,但不会创建该文件.

- (id)init {
    [[NSBundle mainBundle] loadNibNamed:@"PadContent" owner:self options:nil];

    if ([[NSFileManager defaultManager] fileExistsAtPath:[self filePathOfBookmarks]]) {
        bookmarks = [[NSMutableDictionary alloc] 
                      initWithContentsOfFile:[self filePathOfBookmarks]];
    } else {
        bookmarks = [[NSMutableDictionary alloc] init];
        NSLog(@"file does not exist");
    }
    return self;
}

- (void)addBookmark:(id)sender{
    [bookmarks setObject:[dataInstance chapter] forKey:[[dataInstance chapter]title]];
    [bookmarks setObject:[dataInstance chapter] forKey:@"test"];
    NSLog(@"count: %d", [bookmarks count]);
    NSLog([self filePathOfBookmarks]);
    [bookmarks writeToFile:[self filePathOfBookmarks] atomically:YES];
}

- (NSString *) filePathOfBookmarks {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *docDirectory = [paths objectAtIndex:0];
    return [docDirectory stringByAppendingPathComponent:@"bookmarks"];
}

Answer 1

你的字典里有什么？只有某些基础对象可以写出并回读,而无需您做任何额外的工作.如果您的字典包含您定义的自定义对象,则需要使用其他机制来编写和读回数据,例如NSArchiver.我猜[dataInstance chapter]这些基本对象类型中没有任何产量.

有关writeToFile:atomically:可自动读取和写入的数据类型,请参阅NSDictionary的文档.另请参阅NSArchiver和NSCoding协议.