ios - 从自定义对象数组中获取属性的逗号分隔字符串

Question

我有一个自定义对象数组，其中对象具有以下属性 optionID,OptionText。我想为 optionID 属性获取逗号分隔的字符串。在 iOS SDK 中执行此操作的最佳方法是什么。

例如 NSString CommaSeperted = @"1,3,5" 等

Answer 1

NSArray 的类别:

@implementation NSArray(CustomAdditions)

- (NSString *)commaSeparatedStringWithSelector:(SEL)aSelector
{
    NSMutableArray *objects = [NSMutableArray array];

    for (id obj in self)
    {
        if ([obj respondsToSelector:aSelector]) {
            IMP method = [obj methodForSelector:aSelector];
            id (*func)(id, SEL) = (void *)method;
            id customObj = func(obj, aSelector);
            if (customObj && [customObj isKindOfClass:[NSString class]]) {
                [objects addObject:customObj];
            }
        }
    }
    return [objects componentsJoinedByString:@","];
}


@end

例子:

@implementation NSDictionary(Test)

- (NSString*)optionID
{
    return [self objectForKey:@"optionID"];
}

- (NSString*)OptionText
{
    return [self objectForKey:@"OptionText"];
}

@end

NSArray *customObjects = @[@{@"optionID": @"id1", @"OptionText": @"text1" }, @{@"optionID" : @"id2", @"OptionText": @"text2"}];//List of Your custom objects

NSString *commaSeparatedOptionIDs = [customObjects commaSeparatedStringWithSelector:NSSelectorFromString(@"optionID")];

NSString *commaSeparatedOptionTexts = [customObjects commaSeparatedStringWithSelector:NSSelectorFromString(@"OptionText")];