sendSubviewToBack 在 UITableView 中不起作用

Question

我想调整tableView的层次结构。我同时使用了

sendSubviewToBack

和

bringSubviewToFront

来确保 RedCell 在 BlueCell 下，并且我先创建了 RedCell，以便 BlueCell 应该超出 RedCell。（RedCell 中的 overBgView 不应该覆盖 BlueCell）但是，结果如下所示，它不起作用。那么如何确保 RedCell 位于 BlueCell 之下？： 我的代码在这里：

import UIKit

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 2
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        print("<<< \(indexPath)")
        
        if indexPath.row == 0 {
            let cell = tableView.dequeueReusableCell(withIdentifier: RedCell.identifier, for: indexPath) as! RedCell
            // RedCell
            tableView.sendSubviewToBack(cell)
            return cell
        } else {
            let cell = tableView.dequeueReusableCell(withIdentifier: BlueCell.identifier, for: indexPath) as! BlueCell
            // BlueCell
            tableView.bringSubviewToFront(cell)
            return cell
        }
    }
    
    private lazy var tableView: UITableView = {
        let table = UITableView(frame: .zero, style: .plain)
        table.estimatedRowHeight = 80
        table.showsVerticalScrollIndicator = false
        table.separatorStyle = .none
        table.delegate = self
        table.dataSource = self
        table.register(RedCell.self, forCellReuseIdentifier: RedCell.identifier)
        table.register(BlueCell.self, forCellReuseIdentifier: BlueCell.identifier)
        return table
    }()
    
    private lazy var label: UILabel = {
        let label = UILabel()
        label.text = "------split----the views below are not table cell"
        label.textColor = .black
        return label
    }()
    
    private lazy var view1: UIViewOne = {
        let view = UIViewOne()
        return view
    }()
    
    private lazy var view2: UIView = {
        let view = UIView()
        view.backgroundColor = .blue
        return view
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.register(RedCell.self, forCellReuseIdentifier: "redCell")
        tableView.register(BlueCell.self, forCellReuseIdentifier: "blueCell")
        setupUI()
    }
    
    public init() {
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    private func setupUI() {
        view.addSubview(tableView)
        view.addSubview(label)
        view.addSubview(view1)
        view.addSubview(view2)
        
        tableView.snp.makeConstraints { make in
            make.top.equalToSuperview().inset(200)
            make.left.right.equalToSuperview()
            make.height.equalTo(120)
        }
        
        label.snp.makeConstraints { make in
            make.top.equalTo(tableView.snp.bottom).offset(30)
            make.centerX.equalToSuperview()
            make.height.equalTo(20)
        }
        
        view1.snp.makeConstraints { make in
            make.top.equalTo(label.snp.bottom).offset(30)
            make.left.right.equalToSuperview()
            make.height.equalTo(44)
        }
        view2.snp.makeConstraints { make in
            make.top.equalTo(view1.snp.bottom)
            make.left.right.equalToSuperview()
            make.height.equalTo(44)
        }
    }
}

class RedCell: UITableViewCell {
    static let identifier = "RedCell"
    
    private lazy var overBgView: UIView = {
        let view = UIView()
        view.backgroundColor = .yellow
        return view
    }()
    
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        backgroundColor = .red
        setupUI()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func setupUI() {
        contentView.addSubview(overBgView)
//        contentView.sendSubviewToBack(overBgView)
        self.superview?.sendSubviewToBack(overBgView)
        
        overBgView.snp.makeConstraints { make in
            make.top.left.right.equalToSuperview()
            make.height.equalTo(60)
        }
    }
}

class BlueCell: UITableViewCell {
    static let identifier = "BlueCell"
    
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        backgroundColor = .blue
        setupUI()
    }

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

class UIViewOne: UIView {
    private lazy var oversizeView: UIView = {
        let view = UIView()
        view.backgroundColor = .yellow
        return view
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .red
        addSubview(oversizeView)
        oversizeView.snp.makeConstraints { make in
            make.top.left.right.equalToSuperview()
            make.height.equalTo(60)
        }
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

Answer 1

您可以在 tableView 视图 willDisplay 委托函数中修改 tableView 层次结构。