无法在 HeaderView（tableview 的标题视图）中添加 UISearchBar？

Question

无法在 tableView 部分标题中看到 searchBar 一切都以编程方式完成，没有使用故事板

import UIKit

class ConversationsViewController: UITableViewController {
    
    
    
    let searchBar:UISearchBar = {
        let bar = UISearchBar()
        bar.placeholder = "search conversations"
        bar.translatesAutoresizingMaskIntoConstraints = false
        return bar
    }()
    let headerView:UIView = {
        let hView = UIView()
//        hView.backgroundColor = .red
        hView.translatesAutoresizingMaskIntoConstraints = false
        return hView
        
    }()
    //    we want custom cell and header view
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view.
    }
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()

    }
//    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
//        return "section \(section)"
//    }
    override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        headerView.addSubview(searchBar)
        searchBar.centerXAnchor.constraint(equalTo: headerView.centerXAnchor).isActive = true
        searchBar.centerYAnchor.constraint(equalTo: headerView.centerYAnchor).isActive = true
        searchBar.heightAnchor.constraint(equalToConstant: 100).isActive = true
        searchBar.widthAnchor.constraint(equalToConstant: 40).isActive = true
        return headerView
    }
    override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 70
    }
}

这是输出照片

我尝试了不同的方法，但我找到了这种在 tableView 中添加 headerView 的方法，现在我不知道如何在 headerView 中添加该搜索栏，我在上面尝试了但它不起作用，请帮助谢谢

Answer 1

几件事...

节标题的视图应该不将.translatesAutoresizingMaskIntoConstraints 设置为false。将其保留为默认的true。

不要给UISearchBar 一个高度限制——让它使用它的固有高度。

我们确实需要给搜索栏一个宽度限制。如果您希望它适合表格的宽度，请使用：

searchBar.widthAnchor.constraint(equalTo: headerView.widthAnchor, constant: 0.0).isActive = true

如果您希望它只是部分宽度，请将该行的 constant 设为负值，或使用乘数：

// this will make the search bar 90% of the width of the table
searchBar.widthAnchor.constraint(equalTo: headerView.widthAnchor, multiplier: 0.9).isActive = true

这是你的类进行了这些修改：

class ConversationsViewController: UITableViewController {
    
    let searchBar:UISearchBar = {
        let bar = UISearchBar()
        bar.placeholder = "search conversations"
        bar.translatesAutoresizingMaskIntoConstraints = false
        return bar
    }()

    let headerView:UIView = {
        let hView = UIView()

        // give it a background color so we can easily see
        //  if it is laying out correctly
        hView.backgroundColor = .red

        // section header view should leave this at the default TRUE
        //hView.translatesAutoresizingMaskIntoConstraints = false

        return hView
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        // add the searchBar
        headerView.addSubview(searchBar)
        
        // center it horizontally and vertically
        searchBar.centerXAnchor.constraint(equalTo: headerView.centerXAnchor).isActive = true
        searchBar.centerYAnchor.constraint(equalTo: headerView.centerYAnchor).isActive = true
        
        // don't set height constraint - use UISearchBar intrinsic height
        //searchBar.heightAnchor.constraint(equalToConstant: 100).isActive = true
        
        // constrain width equal to headerView width
        //  we can adjust the constant if we don't want it to span the entire width of the table
        //  by using a negative value for the constant, or using a mulitplier to get a percent of the width
        searchBar.widthAnchor.constraint(equalTo: headerView.widthAnchor, constant: 0.0).isActive = true
        
        return headerView
    }
    
    override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 70
    }
    
}