[英]Creating a function to programmatically create UILabels from a String Array in Swift4
我可以以编程方式创建UILabel
,但是在创建函数时,是否必须将其放入viewDidLoad()
方法中? 我需要通过使用self.view.addSubview(label)
将标签附加到视图,但是它引发错误,并且当它位于viewDidLoad()
之外时,构建将失败。
每当我尝试在viewDidLoad
方法之外创建函数时,它都会声明“使用未解决的标识符自身”。 有没有办法解决?
另外,当我将函数放入viewDidLoad
一切工作正常,并且创建了标签,但它们彼此重叠。 如果可能,我是否希望标签彼此相邻?
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)
}
}
}
为了管理这样的几何图形, UIStackView
可能有用。 同样,当您要以编程方式初始化和管理视图时,也不需要在viewDidLoad中调用此方法,loadView生命周期方法对此更合适。
class ViewController: UIViewController {
private let vstackView = UIStackView()
private let horizontal_spacing = 20.0
private let spaceConstantForLetter = 10.0
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
vstackView.axis = .vertical
vstackView.translatesAutoresizingMaskIntoConstraints = false
vstackView.alignment = .center
vstackView.spacing = 10
self.view.addSubview(vstackView)
vstackView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
vstackView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
createALabel(inputtedString: "this is a long test string that exceeds screen width")//
// Do any additional setup after loading the view.
}
func createALabel(inputtedString: String) -> Void {
let string = inputtedString
let test = string.components(separatedBy: " ")
var horizontalStackList = [UILabel] ()
for (index, element) in test.enumerated() {
let label = UILabel()
label.textAlignment = .center
label.textColor = UIColor.blue
label.text = element
label.layer.borderColor = UIColor.blue.cgColor
label.layer.borderWidth = 1.0
horizontalStackList.append(label)
let totalLetterNumber = horizontalStackList.map { $0.text!.count }.reduce(0, +)
let contentWidth = Double(totalLetterNumber) * spaceConstantForLetter //constant for a letter that takes how much space from screen
let spacingWidth = Double(horizontalStackList.count - 1) * horizontal_spacing
/*add left and right margins if exist*/
if((CGFloat(spacingWidth + contentWidth) > UIScreen.main.bounds.width) || index == test.count - 1) {
let exceedingLabel = horizontalStackList.popLast()
let hstackView = UIStackView(arrangedSubviews: horizontalStackList)
hstackView.axis = .horizontal
hstackView.translatesAutoresizingMaskIntoConstraints = false
hstackView.spacing = CGFloat(horizontal_spacing)
hstackView.alignment = .center
vstackView.addArrangedSubview(hstackView)
horizontalStackList.removeAll(keepingCapacity: false)
horizontalStackList.append(exceedingLabel!)
}
}
}
}
编辑:换行添加为爵士想要
最好使用收集视图。 它使您的工作更加轻松。 尝试这个
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]))
}
}
您必须添加一个Integer变量来设置x位置。 在这里我根据x位置设置了xPos变量
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: " ")
let xPos = 0
for element in test {
let label = UILabel(frame: CGRect(x: xPos, y: 0, width: 60, height: 35))
// label.center = CGPoint(x: 160, y: 285)
label.textAlignment = .center
xPos = xPos + 60 + 10 // Update xPos width 60 & 10 is gap between two label
label.textColor = UIColor.blue
label.text = element
label.layer.borderColor = UIColor.blue.cgColor
label.layer.borderWidth = 3.0
self.view.addSubview(label)
}
}
}
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