Question

我有一个名为Hashtag的模型对象。这只包含一个名为hashtagName的可选String变量。我从Firebase数据库中获取数据，并将主题标签附加到我的fashionHashtags，即[Hashtag]。我遇到的问题是我想通过使用insertElementAtIndexPath函数将其附加到我的其他categoriesArray。我不能这样做因为它想要一个字符串数组而不是一个Hashtag数组。当我自动更正它时，它会用fashionHashtags as! [String]替换它，但这会产生另一个错误。我如何解决这个问题，这样我才能这样做？我想坚持Model Object的做事方式。感谢你们。答案将受到高度赞赏。代码如下：

class Hashtag: NSObject {

    vvar hashtagName: String?
}

private let reuseIdentifier = "Cell"

class HashtagView: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    var catagoriesArray: [String] = ["FASHION", "FOOD", "HOBBIES", "MUSIC"]

    var fashionHashtags = [Hashtag]()
    var foodHashtags = [Hashtag]()
    var hobbiesHashtags = [Hashtag]()
    var musicHashtags = [Hashtag]()

    var hashtagsArray: [String] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        self.hashtagsArray.removeAll()

        self.navigationController?.navigationBar.tintColor = .white
        navigationItem.title = "Hashtag"

        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Finished", style: .plain, target: self, action: #selector(finishSelectingHashtags))

        self.collectionView?.backgroundColor = .white
        self.collectionView?.register(HashtagCell.self, forCellWithReuseIdentifier: reuseIdentifier)
        self.collectionView?.contentInset = UIEdgeInsetsMake(10, 0, 0, 0)

        handleFetchFashionHashtags()
    }

    func insertElementAtIndexPath(element: [String], index: Int) {
        catagoriesArray.insert(contentsOf: element, at: index)
    }

    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

        if indexPath.item == 0 {
            insertElementAtIndexPath(element: fashionHashtags, index: indexPath.item + 1)

            self.collectionView?.performBatchUpdates(
                {
                    self.collectionView?.reloadSections(NSIndexSet(index: 0) as IndexSet)
            }, completion: { (finished:Bool) -> Void in

            })
        }

    }

Answer 1

根据我的理解，可能会有几种不同的方法。这将是循环遍历Hashtag对象数组并将hashtagName字符串属性附加到stringsArray字符串的方法。

    for hashTagItem in fashionHashtags {
        if let hashTag = hashTagItem.hashtagName {
             // Appends to categoriesArray as a string
             categoriesArray.append(hashTag)
        }
    }

另一种方法是构建一组字符串，然后在有意义的时候插入它。

    var hashTagString: [Strings] = []
    for hashTagItem in fashionHashtags {
        if let hashTag = hashTagItem.hashtagName {
             hashTagStrings.append(hashTag)
        }
    }
    // Insert or add the hash tag strings as it makes sense
    categoriesArray += hashTagStrings  // Add all at once if it makes sense

Swift：无法将NSObject插入到Array中，因为它需要[String]

1 个答案: