ios – 替换NSNull中嵌套NSDictionary中的事件

这个问题类似于 this question,但是这种方法只适用于字典的根级别.

我正在用空字符串替换任何NSNull值的发生,所以我可以将完整的字典保存到plist文件(如果我添加NSNull的文件将不会写入).

但是,我的字典里面有嵌套的字典.喜欢这个：

"dictKeyName" = {
    innerStrKeyName = "This is a string in a dictionary";
    innerNullKeyName = "<null>";
    innerDictKeyName = {
        "innerDictStrKeyName" = "This is a string in a Dictionary in another Dictionary";
        "innerDictNullKeyName" = "<null>";
    };
};

如果我使用：

@interface NSDictionary (JRAdditions)
- (NSDictionary *) dictionaryByReplacingNullsWithStrings;
@end
 
@implementation NSDictionary (JRAdditions)
 
- (NSDictionary *) dictionaryByReplacingNullsWithStrings {
 
    const NSMutableDictionary *replaced = [NSMutableDictionary dictionaryWithDictionary:self];
    const id nul = [NSNull null];
    const NSString *blank = @"";
 
    for(NSString *key in replaced) {
        const id object = [self objectForKey:key];
        if(object == nul) {
            [replaced setObject:blank forKey:key];
        }
    }
    return [NSDictionary dictionaryWithDictionary:replaced];
}
 
@end

我得到这样的东西：

"dictKeyName" = {
    innerStrKeyName = "This is a string in a dictionary";
    innerNullKeyName = ""; <-- this value has changed
    innerDictKeyName = {
        "innerDictStrKeyName" = "This is a string in a Dictionary in another Dictionary";
        "innerDictNullKeyName" = "<null>"; <-- this value hasn't changed
    };
};

有没有办法从所有字典中查找每个NSNull值,包括嵌套字典？？

编辑：
数据正在从JSON Feed中获取,因此我收到的数据是动态的(我不想每次更改Feed时都更新该应用).

解决方法

该方法的一个小修改可以使其递归：

@interface NSDictionary (JRAdditions)
- (NSDictionary *) dictionaryByReplacingNullsWithStrings;
@end
 
@implementation NSDictionary (JRAdditions)
 
- (NSDictionary *) dictionaryByReplacingNullsWithStrings {
    const NSMutableDictionary *replaced = [NSMutableDictionary dictionaryWithDictionary: self];
    const id nul = [NSNull null];
    const NSString *blank = @"";
 
    for (NSString *key in self) {
        const id object = [self objectForKey: key];
        if (object == nul) {
            [replaced setObject: blank forKey: key];
        }
        else if ([object isKindOfClass: [NSDictionary class]]) {
            [replaced setObject: [(NSDictionary *) object dictionaryByReplacingNullsWithStrings] forKey: key];
        }
    }
    return [NSDictionary dictionaryWithDictionary: replaced];
}

请注意,快速枚举现在是自己,而不是替换

上面的代码,这个例子：

NSMutableDictionary *dic1 = [NSMutableDictionary dictionary];
[dic1 setObject: @"string 1" forKey: @"key1.1"];
[dic1 setObject: [NSNull null] forKey: @"key1.2"];
 
NSMutableDictionary *dic2 = [NSMutableDictionary dictionary];
[dic2 setObject: @"string 2" forKey: @"key2.1"];
[dic2 setObject: [NSNull null] forKey: @"key2.2"];
 
[dic1 setObject: dic2 forKey: @"key1.3"];
 
NSLog(@"%@",dic1);
NSLog(@"%@",[dic1 dictionaryByReplacingNullsWithStrings]);

呈现此结果：

2012-09-01 08:30:16.210 Test[57731:c07] {
    "key1.1" = "string 1";
    "key1.2" = "<null>";
    "key1.3" =     {
        "key2.1" = "string 2";
        "key2.2" = "<null>";
    };
}
2012-09-01 08:30:16.212 Test[57731:c07] {
    "key1.1" = "string 1";
    "key1.2" = "";
    "key1.3" =     {
        "key2.1" = "string 2";
        "key2.2" = "";
    };

ios – 替换NSNull中嵌套NSDictionary中的事件

解决方法

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