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iOS UITableView
A view controller at a minimum must adhere to the UITableViewDelegate and UITableViewDatasource protocols.
UIRefreshControls are designed to work only with UITableViews or UITableViewControllers.
import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
@IBOutlet weak var tableView: UITableView!
var refreshControl = UIRefreshControl()
override func viewDidLoad() {
super.viewDidLoad()
/*
A UIRefreshControl sends a `valueChanged` event to signal
when a refresh should occur.
*/
refreshControl.addTarget(self, action: #selector(ViewController.refresh), for: .valueChanged)
tableView.addSubview(refreshControl)
}
@objc private func refresh() {
...
// Hide refresh control
if refreshControl.isRefreshing {
refreshControl.endRefreshing()
}
}
To allow AutoLayout to dynamically size UITableViewCell instances, the following two lines are necessary in a view controller.
tableView.estimatedRowHeight = 100.0
tableView.rowHeight = UITableViewAutomaticDimensionUsually, cell height is defined by the tableView:heightForRowAtIndexPath method from the UITableViewDelegate protocol.
estimatedRowHeight gives the tableView an approximate height for each cell. This value is used to calculate scroll bar heights and positioning, among other things.
tableView.estimatedRowHeight = 100.0
Automatic sizing uses AutoLayout constraints to calculate height.
tableView.rowHeight = UITableViewAutomaticDimension
Both estimatedRowHeight and UITableViewAutomaticDimension must be set.