swift - 结果页面上出现空白屏幕 : where did it go?

Question

在此阶段，应用程序应该显示测验的结果。因为我希望名称以与描述不同的行/不同的字体显示，所以我将其分成两个标签。目前，这两个标签都没有出现。我认为这个问题来自 setUpViews 和/或约束，但我不确定。

import UIKit
class ResultsController: UIViewController {

let resultsLabel: UILabel = {
    let rlbl = UILabel()
    rlbl.text = "Congratulations!"
    rlbl.contentMode = .scaleToFill
    rlbl.numberOfLines = 0
    rlbl.translatesAutoresizingMaskIntoConstraints = false
    rlbl.textAlignment = .center
    rlbl.font = UIFont(name: "USIS 1949", size: 50)
    rlbl.adjustsFontSizeToFitWidth = true
    rlbl.numberOfLines=0
    rlbl.sizeToFit()
    rlbl.minimumScaleFactor = 0.1
    return rlbl
}()

let descriptionLabel: UILabel = {
    let dlbl = UILabel()
    dlbl.text = "Congratulations!"
    dlbl.contentMode = .scaleToFill
    dlbl.numberOfLines = 0
    dlbl.translatesAutoresizingMaskIntoConstraints = false
    dlbl.textAlignment = .justified
    dlbl.font = UIFont(name: "Flama", size: 30)
    return dlbl
}()

func setupViews() {
    self.view.addSubview(resultsLabel)
    resultsLabel.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 150).isActive=true
    resultsLabel.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive=true
    resultsLabel.widthAnchor.constraint(equalToConstant: 500).isActive=true

    self.view.addSubview(descriptionLabel)
    descriptionLabel.topAnchor.constraint(equalTo: resultsLabel.bottomAnchor, constant: 20).isActive=true
    descriptionLabel.heightAnchor.constraint(equalToConstant: 50).isActive=true
    descriptionLabel.widthAnchor.constraint(equalToConstant: 150).isActive=true
    descriptionLabel.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive=true
    descriptionLabel.centerYAnchor.constraint(equalTo: self.view.centerYAnchor, constant: 0).isActive=true
}

override func viewDidLoad() {
    super.viewDidLoad()

    navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(done(sender:)))

    navigationItem.title = "Results"

    view.backgroundColor = UIColor.white

    let names = ["Ross", "Joey", "Chandler", "Monica", "Rachel", "Phoebe"]

    let additional = ["Ross", "Joey", "Chandler", "Monica", "Rachel", "Phoebe"]

    var score = 0
    for question in QuestionController.questionsList {
        score += question.selectedAnswerIndex!
    }

    let result = names[score % names.count]
    resultsLabel.text = "\(result)"

    let description = additional[score % additional.count]
    descriptionLabel.text = "\(description)"

}

    @objc func done(sender: UIBarButtonItem) {

    navigationController?.popToRootViewController(animated: true)

}

}

class QuestionHeader: UITableViewHeaderFooterView {

override init(reuseIdentifier: String?) {
    super.init(reuseIdentifier: reuseIdentifier)
    setupViews()
}

let nameLabel: UILabel = {
    let label = UILabel()
    label.text = "Sample Question"
    label.font = UIFont.boldSystemFont(ofSize: 30)
    label.translatesAutoresizingMaskIntoConstraints = false
    return label
}()

func setupViews() {
    addSubview(nameLabel)
    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-16-[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))
    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

}

class AnswerCell: UITableViewCell {

override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
    super.init(style: style, reuseIdentifier: reuseIdentifier)
    setupViews()
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

let nameLabel: UILabel = {
    let label = UILabel()
    label.text = "Sample Answer"
    label.font = UIFont.systemFont(ofSize: 30)
    label.translatesAutoresizingMaskIntoConstraints = false
    return label
}()

func setupViews() {
    addSubview(nameLabel)
    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-16-[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))
    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))
}

 }

Answer 1

如果引用 ResultsController，您不会在 viewDidLoad() 中调用 setUpViews()。