ios - 创建一个函数以在 Swift4 中从字符串数组以编程方式创建 UILabel

Question

我能够以编程方式创建一个 UILabel，但是当我创建一个函数时，我必须将它放在 viewDidLoad() 方法中吗？我需要使用 self.view.addSubview(label) 将标签附加到 View ，但它会引发错误，然后当它在 viewDidLoad() 之外时我的构建失败。

每当我尝试在 viewDidLoad 方法之外创建函数时，它都会声明“使用未解析的标识符自身”。有没有办法解决？

此外，当我将函数放在 viewDidLoad 中时，一切正常，并且创建了标签，但它们是在彼此之上创建的。如果可能，我希望标签彼此相邻？

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    func createALabel(inputtedString: String) -> Void {
        let string = inputtedString
        let test = string.components(separatedBy: " ")

        for element in test {
            let label = UILabel(frame: CGRect(x: 0, y: 0, width: 60, height: 35))
            label.center = CGPoint(x: 160, y: 285)
            label.textAlignment = .center
            label.textColor = UIColor.blue
            label.text = element
            label.layer.borderColor = UIColor.blue.cgColor
            label.layer.borderWidth = 3.0
            self.view.addSubview(label)
        }
    }
}

Even with the position change my labels are still stacking

Answer 1

使用 Collection View 是最好的选择。它使您的工作更轻松。试试这个

class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {

    let collectionView = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())
    var wordsArr = [String]()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        collectionView.backgroundColor = .white
        collectionView.delegate = self
        collectionView.dataSource = self
        collectionView.register(WordCell.self, forCellWithReuseIdentifier: "WordCell")
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(collectionView)
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-(5)-[collectionView]-(5)-|", options: [], metrics: nil, views: ["collectionView":collectionView]))
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-(5)-[collectionView]-(5)-|", options: [], metrics: nil, views: ["collectionView":collectionView]))

        createALabel(inputtedString: "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam")
    }
    func createALabel(inputtedString: String) -> Void {
        wordsArr = inputtedString.components(separatedBy: " ")
        collectionView.reloadData()
    }
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return wordsArr.count
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "WordCell", for: indexPath) as? WordCell ?? WordCell()
        cell.label.text = wordsArr[indexPath.row]
        return cell
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let width = (wordsArr[indexPath.row] as NSString).boundingRect(with: CGSize.zero, options: .usesLineFragmentOrigin, attributes: [.font: UIFont.systemFont(ofSize: 16.0)], context: nil).size.width
        let size = CGSize(width: width + 10
            , height: 35)
        return size
    }

}
class WordCell: UICollectionViewCell {

    let label = UILabel()

    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }
    func commonInit() {

        backgroundColor = .white

        label.font = UIFont.systemFont(ofSize: 16.0)
        label.textAlignment = .center
        label.textColor = UIColor.blue
        label.layer.borderColor = UIColor.blue.cgColor
        label.layer.borderWidth = 3.0
        label.translatesAutoresizingMaskIntoConstraints = false
        addSubview(label)

        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[label(35)]|", options: [], metrics: nil, views: ["label":label]))
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[label]|", options: [], metrics: nil, views: ["label":label]))
    }
}