为啥我的 UITableViewController 页脚高度不会改变？

Posted 2023-02-24

【中文标题】为啥我的 UITableViewController 页脚高度不会改变？

【英文标题】：Why won't my UITableViewController footer height change?为什么我的 UITableViewController 页脚高度不会改变？

【发布时间】：2020-05-15 22:32:40

【问题描述】：

我正在 Swift Playgrounds 中编写一个模拟消息应用程序，为了保存消息，我有一个带有自定义单元格的 UITableViewController。我正在尝试在表格中添加一个“粘性”页眉和页脚，它们将分别保存导航控件、消息输入和发送按钮。不过，我似乎无法更改页眉和页脚的高度。我尝试过使用tableView(_:heightForFooterInSection:) & tableView(_:heightForHeaderInSection:)，但这也不起作用。

这是我目前所拥有的：

import UIKit
import PlaygroundSupport

class ViewController: UITableViewController 

    var textMessages = [
        "Here's my very first message",
        "I'm going to message another long message that will word wrap",
        "I'm going to message another long message that will word wrap, I'm going to message another long message that will word wrap, I'm going to message another long message that will word wrap",
        "some messaging"
    ]

    override func viewDidLoad() 
        super.viewDidLoad()

        navigationItem.title = "Messages"
        navigationController?.navigationBar.prefersLargeTitles = true

        tableView.register(ChatMessageCell.self, forCellReuseIdentifier: "cell_1")
        tableView.separatorStyle = .none

        adddatextbruh()

    

    override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView?
        let customView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 75))
        customView.backgroundColor = UIColor.red
        let button = UIButton(frame: CGRect(x: 0, y: 0, width: 100, height: 75))
        button.setTitle("Submit", for: .normal)
        //button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)
        customView.addSubview(button)
        return customView
    

    override func tableView(_ tableView: UITableView, viewForFooterInSection section: Int) -> UIView?
        let customView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 75))
        customView.backgroundColor = UIColor.red
        let button = UIButton(frame: CGRect(x: 0, y: 0, width: 100, height: 75))
        button.setTitle("Submit", for: .normal)
        //button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)
        customView.addSubview(button)
        return customView
    

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int 
        return textMessages.count
    

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell 
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell_1", for: indexPath) as! ChatMessageCell
        cell.selectionStyle = .none

        if indexPath.row % 2 == 1
            cell.messageLabel.text = textMessages[indexPath.row]
            //cell.setupConstraints(side: 1)
            cell.bubbleBackgroundView.backgroundColor = UIColor(white: 0.9, alpha: 1)
            return cell
        else
            cell.messageLabel.text = textMessages[indexPath.row]
            //cell.setupConstraints(side: 0)
            cell.bubbleBackgroundView.backgroundColor = .blue
            return cell
        
    
    //let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath) as! ChatMessageCell
    //        cell.textLabel?.text = "We want to provide a longer string that is actually going to wrap onto the next line and maybe even a third line."
    //        cell.textLabel?.numberOfLines = 0
    func adddatextbruh()
        textMessages.append("hey whats up")
        tableView.beginUpdates()
        tableView.insertRows(at: [
            (NSIndexPath(row: textMessages.count-1, section: 0) as IndexPath)], with: .automatic)
        tableView.endUpdates()
        tableView.scrollToRow(at: IndexPath(row: textMessages.count-1, section: 0), at: UITableView.ScrollPosition.bottom, animated: true)
    





class ChatMessageCell: UITableViewCell 

    let messageLabel = UILabel()
    let bubbleBackgroundView = UIView()
    var leadingAnchorConstant = CGFloat()

    func setupConstraints(side: Int)
        if side == 1
            leadingAnchorConstant = frame.size.width - 176
        else
            leadingAnchorConstant = 32
        
    

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) 
        super.init(style: style, reuseIdentifier: reuseIdentifier)

        bubbleBackgroundView.backgroundColor = .yellow
        let gradient = CAGradientLayer()

        bubbleBackgroundView.layer.shadowOpacity = 0.35
        bubbleBackgroundView.layer.shadowRadius = 6
        bubbleBackgroundView.layer.shadowOffset = CGSize(width: 0, height: 0)
        bubbleBackgroundView.layer.shadowColor = UIColor.black.cgColor

        bubbleBackgroundView.layer.cornerRadius = 25
        bubbleBackgroundView.translatesAutoresizingMaskIntoConstraints = false
        addSubview(bubbleBackgroundView)

        addSubview(messageLabel)
        //        messageLabel.backgroundColor = .green
        messageLabel.text = "We want to provide a longer string that is actually going to wrap onto the next line and maybe even a third line."
        messageLabel.numberOfLines = 0

        messageLabel.translatesAutoresizingMaskIntoConstraints = false

        // lets set up some constraints for our label
        let constraints = [messageLabel.topAnchor.constraint(equalTo: topAnchor, constant: 32),
                           messageLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 32),
                           messageLabel.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -32),
                           messageLabel.widthAnchor.constraint(equalToConstant: 250),

                           bubbleBackgroundView.topAnchor.constraint(equalTo: messageLabel.topAnchor, constant: -16),
                           bubbleBackgroundView.leadingAnchor.constraint(equalTo: messageLabel.leadingAnchor, constant: -16),
                           bubbleBackgroundView.bottomAnchor.constraint(equalTo: messageLabel.bottomAnchor, constant: 16),
                           bubbleBackgroundView.trailingAnchor.constraint(equalTo: messageLabel.trailingAnchor, constant: 16),
        ]

        NSLayoutConstraint.activate(constraints)

        //        messageLabel.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
    

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



PlaygroundPage.current.liveView = ViewController()

【参考方案1】：

跟随功能不是为了高度

override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? 
        <#code#>
    

下一个函数是高度。

    override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat 
        return your_height
    

【参考方案2】：

解决了。我只是在 viewDidLoad() 中设置了tableView.sectionFooterHeight = //the height。不知道为什么 heightForFooterInSection/headerInSection 不起作用，但对我来说这无论如何都要干净得多。

【讨论】：

因为高度需要用到这个函数：func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat return 50