在滚动视图中看不到表格视图

Question

I am trying to add a table view to my scroll view:

class ViewController: UIViewController {
    
    let tableView = UITableView()

    override func viewDidLoad() {
        super.viewDidLoad()

        let scrollView = UIScrollView()
        scrollView.backgroundColor = .red

        
        view.addSubview(scrollView)
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            scrollView.topAnchor.constraint(equalTo: view.topAnchor),
            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
        
        scrollView.addSubview(tableView)
        
        tableView.backgroundColor = .yellow
        tableView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: scrollView.topAnchor),
            tableView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
            tableView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
            tableView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor)
        ])
        
        scrollView.contentSize = CGSize(width: view.bounds.width, height: 2000)
    }


}

However it doesn't show. It only shows the scrollview background color. What am I doing wrong here?

Answer 1

Is that all of the code in your test? You've not set the datasource and delegate of the tableview, and haven't returned any cells so it's not going to show anything.

Answer 2

The problem is the constraint for tableView in NSLayoutConstraint.

tableView.topAnchor.constraint(equalTo: scrollView.topAnchor),
tableView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
tableView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
tableView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor)

You use view.bottomAnchor or anyothers instead of scrollView, such as:

tableView.topAnchor.constraint(equalTo: view.topAnchor),
tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor)

This will display your tableView. Now you can try to fight with other problems caused by put tableView inside scrollView.

Answer 3

Don't use Scrollview under Tableview , it will make scrollview useless . Tableview has inbuilt scrollview(kind of) as you fill up the tables, if the tables row is many and go beyond your screen then scrollview in tableview is automatically enabled. So,Use only tableview.

Answer 4

Add heightAnchor constraint to your table view to fix this issue. For example:

tableView.heightAnchor.constraint(equalToConstant: 4 * 80)

This example add height anchor to the table view (4 is number of rows, 80 is height of a row)