问题描述
我需要根据符号数组中对象的数量在屏幕上显示标签,数组中有 5 个对象,屏幕上有 4 个标签(如屏幕截图所示),有什么问题?下面附上代码
class ViewController: UIViewController {
var symbols = ["1","2","3","4","5"]
let mySpacing: CGFloat = 5.0
let widthLabelInFormula = 50
let formulaStackView = UIStackView()
var symbolLabels: [UILabel] = []
override func viewDidLoad() {
super.viewDidLoad()
let widthFormula: CGFloat = CGFloat(50 * symbols.count - symbols.count * 50)
formulaStackView.axis = .horizontal
formulaStackView.alignment = .fill
formulaStackView.distribution = .fillEqually
formulaStackView.spacing = mySpacing
formulaStackView.backgroundColor = #colorLiteral(red: 1,green: 1,blue: 1,alpha: 1)
view.addSubview(formulaStackView)
// add constraints
formulaStackView.translatesAutoresizingMaskIntoConstraints = false
formulaStackView.heightAnchor.constraint(equalToConstant: 50).isActive = true
formulaStackView.widthAnchor.constraint(equalToConstant: widthFormula).isActive = true
formulaStackView.topAnchor.constraint(equalTo: view.topAnchor,constant: 250).isActive = true
addLabels(formulaStackView: formulaStackView)
}
func addLabels(formulaStackView: UIStackView) {
for _ in 0 ..< symbols.count {
addLabel(formulaStackView: formulaStackView)
}
print(symbolLabels.count) // 5
}
func addLabel(formulaStackView: UIStackView) {
let symbolLabel = UILabel()
symbolLabel.backgroundColor = #colorLiteral(red: 0.09019608051,green: 0,blue: 0.3019607961,alpha: 1)
symbolLabel.textColor = #colorLiteral(red: 1.0,green: 1.0,blue: 1.0,alpha: 1.0)
symbolLabel.textAlignment = .center
symbolLabel.font = UIFont.systemFont(ofSize: 20)
symbolLabel.text = "?"
// add constraints
symbolLabel.heightAnchor.constraint(equalToConstant: 50).isActive = true
symbolLabel.widthAnchor.constraint(equalToConstant: 50).isActive = true
symbolLabel.translatesAutoresizingMaskIntoConstraints = false
symbolLabels.append(symbolLabel)
formulaStackView.addArrangedSubview(symbolLabel)
}
}
解决方法
这里的问题是您在这一行中将堆栈视图的宽度设置为零:
let widthFormula: CGFloat = CGFloat(50 * symbols.count - symbols.count * 50) // 0
您实际上可以删除上面的行和这一行:
formulaStackView.widthAnchor.constraint(equalToConstant: widthFormula).isActive = true
因为 UIKit 可以自动设置。
完成代码
class ViewController: UIViewController {
var symbols = ["1","2","3","4","5"]
let mySpacing: CGFloat = 5.0
let widthLabelInFormula = 50
let formulaStackView = UIStackView()
var symbolLabels: [UILabel] = []
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
// let widthFormula: CGFloat = CGFloat(50 * symbols.count - symbols.count * 50)
formulaStackView.axis = .horizontal
formulaStackView.alignment = .fill
formulaStackView.distribution = .fillEqually
formulaStackView.spacing = mySpacing
formulaStackView.backgroundColor = #colorLiteral(red: 1,green: 1,blue: 1,alpha: 1)
view.addSubview(formulaStackView)
// add constraints
formulaStackView.translatesAutoresizingMaskIntoConstraints = false
formulaStackView.heightAnchor.constraint(equalToConstant: 50).isActive = true
// formulaStackView.widthAnchor.constraint(equalToConstant: widthFormula).isActive = true
formulaStackView.topAnchor.constraint(equalTo: view.topAnchor,constant: 250).isActive = true
addLabels(formulaStackView: formulaStackView)
}
func addLabels(formulaStackView: UIStackView) {
for _ in 0 ..< symbols.count {
addLabel(formulaStackView: formulaStackView)
}
print(symbolLabels.count) // 5
}
func addLabel(formulaStackView: UIStackView) {
let symbolLabel = UILabel()
symbolLabel.translatesAutoresizingMaskIntoConstraints = false
symbolLabel.backgroundColor = #colorLiteral(red: 0.09019608051,green: 0,blue: 0.3019607961,alpha: 1)
symbolLabel.textColor = #colorLiteral(red: 1.0,green: 1.0,blue: 1.0,alpha: 1.0)
symbolLabel.textAlignment = .center
symbolLabel.font = UIFont.systemFont(ofSize: 20)
symbolLabel.text = "?"
// add constraints
symbolLabel.heightAnchor.constraint(equalToConstant: 50).isActive = true
symbolLabel.widthAnchor.constraint(equalToConstant: 50).isActive = true
symbolLabels.append(symbolLabel)
formulaStackView.addArrangedSubview(symbolLabel)
}
}