UITableView 自定义单元格高度不起作用

Question

我正在学习如何以编程方式使用 UIKit，并创建了一个自定义 UITableViewCell，但我的行高没有注册。

我不断收到此错误

[警告] 仅警告一次：检测到约束不明确的情况 建议表格视图单元格的内容视图高度为零。 我们正在考虑意外折叠并改用标准高度。

即使在谷歌搜索错误之后，我似乎也无法理解/找到我的代码的问题所在。

视图控制器：

import UIKit

class ViewController: UIViewController {

    let contacts = ContactAPI.getContacts()
    let tableView = UITableView()
    var safeArea: UILayoutGuide!
    //let contentView = UIView()
 
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        safeArea = view.layoutMarginsGuide

        setUpTable()
        setUpNavigation()
    }
    
    func setUpTable(){
        view.addSubview(tableView)
                
        //populate with data
        tableView.dataSource = self
        tableView.register(TableViewCell.self, forCellReuseIdentifier: "cell")
        
        //turn off autoresizing
        tableView.translatesAutoresizingMaskIntoConstraints = false
        
        //Layout Configs
        tableView.topAnchor.constraint(equalTo: safeArea.topAnchor).isActive = true
        tableView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        tableView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
       
    }
    
    func setUpNavigation(){
        navigationItem.title = "Contacts"
        self.navigationController?.navigationBar.barTintColor = .gray
        self.navigationController?.navigationBar.isTranslucent = false
        self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]
    }


}

extension ViewController: UITableViewDataSource{
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return contacts.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell
        //cell.textLabel?.text = contacts[indexPath.row].name
        cell.contact = contacts[indexPath.row]
        return cell
    }
    
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 100.0
    }
}

自定义单元：

class TableViewCell: UITableViewCell {

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?){
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        
        self.contentView.addSubview(profileImage)
        subView.addSubview(nameLabel)
        subView.addSubview(jobTitleLabel)
        self.contentView.addSubview(subView)
        self.contentView.addSubview(flagImage)
        
        profileImage.centerYAnchor.constraint(equalTo:self.contentView.centerYAnchor).isActive = true
        profileImage.leadingAnchor.constraint(equalTo:self.contentView.leadingAnchor, constant:10).isActive = true
        profileImage.widthAnchor.constraint(equalToConstant:70).isActive = true
        profileImage.heightAnchor.constraint(equalToConstant:70).isActive = true
        
        subView.centerYAnchor.constraint(equalTo:self.contentView.centerYAnchor).isActive = true
        subView.leadingAnchor.constraint(equalTo:self.profileImage.trailingAnchor, constant:10).isActive = true
        subView.trailingAnchor.constraint(equalTo:self.contentView.trailingAnchor, constant:-10).isActive = true
        subView.heightAnchor.constraint(equalToConstant:40).isActive = true
        
        nameLabel.topAnchor.constraint(equalTo:self.subView.topAnchor).isActive = true
        nameLabel.leadingAnchor.constraint(equalTo:self.subView.leadingAnchor).isActive = true
        nameLabel.trailingAnchor.constraint(equalTo:self.subView.trailingAnchor).isActive = true
        
        jobTitleLabel.topAnchor.constraint(equalTo:self.nameLabel.bottomAnchor).isActive = true
        jobTitleLabel.leadingAnchor.constraint(equalTo:self.subView.leadingAnchor).isActive = true
        jobTitleLabel.topAnchor.constraint(equalTo:self.nameLabel.bottomAnchor).isActive = true
        jobTitleLabel.leadingAnchor.constraint(equalTo:self.subView.leadingAnchor).isActive = true
        
        flagImage.widthAnchor.constraint(equalToConstant:26).isActive = true
        flagImage.heightAnchor.constraint(equalToConstant:26).isActive = true
        flagImage.trailingAnchor.constraint(equalTo:self.contentView.trailingAnchor, constant:-20).isActive = true
        flagImage.centerYAnchor.constraint(equalTo:self.contentView.centerYAnchor).isActive = true
    }

    required init?(coder aDecoder: NSCoder){
        super.init(coder: aDecoder)
    }
    
    //Profile Image
    let profileImage: UIImageView = {
        let img = UIImageView()
        img.contentMode = .scaleAspectFill
        img.translatesAutoresizingMaskIntoConstraints = false
        img.layer.cornerRadius = 35
        img.clipsToBounds = true
        return img
    }()
    
    //Name
    let nameLabel: UILabel = {
        let label = UILabel()
        label.font = UIFont.boldSystemFont(ofSize: 20)
        label.textColor = .gray
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()
    
    //Job Title
    let jobTitleLabel: UILabel = {
        let label = UILabel()
        label.font = UIFont.boldSystemFont(ofSize: 14)
        label.textColor = .white
        label.backgroundColor = .gray
        label.layer.cornerRadius = 5
        label.clipsToBounds = true
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()
    
    //Container for Name and Job Title
    let subView: UIView = {
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.clipsToBounds = true
        return view
    }()
    
    //Country Flag
    let flagImage: UIImageView = {
        let img = UIImageView()
        img.contentMode = .scaleAspectFill
        img.translatesAutoresizingMaskIntoConstraints = false
        img.layer.cornerRadius = 13
        img.clipsToBounds = true
        return img
    }()
    
    var contact:Contact? {
        didSet{
            guard let contactItem = contact else {return}
            
            if let name = contactItem.name{
                profileImage.image = UIImage(named: name)
                nameLabel.text = name
            }
            
            if let jobTitle = contactItem.jobTitle{
                jobTitleLabel.text = "\(jobTitle)"
            }
            
            if let country = contactItem.country{
                flagImage.image = UIImage(named: country)
            }
        }
    }
    
}

Answer 1

你还没有实现UITableViewDelegate

在您的setupTable() 中添加该行

tableView.delegate = self

然后更改您的扩展名

extension ViewController: UITableViewDataSource {

到extension ViewController: UITableViewDataSource, UITableViewDelegate {