我正在创建一个登录系统,我不希望在用户名字段中允许使用空格.我想阻止添加空格,而不是检查和验证字段.
因此,每次用户按空格键时,都不会发生任何事情.我怎样才能做到这一点？我见过Instagram这样做.
到目前为止这是我的代码:
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
@IBOutlet weak var signUp: UIBarButtonItem!
@IBOutlet weak var navBar: UINavigationBar!
@IBOutlet weak var UsernameText: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.navigationController?.navigationBar.clipsToBounds = true
UsernameText.attributedPlaceholder = NSAttributedString(string:"TypeYourUsername",
attributes:[NSForegroundColorAttributeName: UIColor.whiteColor()])
func textField(UsernameText: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if (string == " ") {
return false
}
return true
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func …我正在使用Swift 4创建一个iOS应用程序而我没有使用Storyboard.要从Table View Controller中删除行,用户会向左滑动该行,然后单击"删除"按钮.
这是我用来实现的代码(没有使用外部库):
override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
self.isAccessibilityElement = true
self.accessibilityLabel = "Delete row"
let deleteAction = UIContextualAction(style: .normal , title: "DELETE") { (action, view, handler) in
self.removeRowFromMyList(indexPath: indexPath.row)
MyListController.stations.remove(at: indexPath.row)
self.tableView.deleteRows(at: [indexPath], with: .automatic)
self.tableView.setEditing(false, animated: true)
self.tableView.reloadData()
}
let swipeAction = UISwipeActionsConfiguration(actions: [deleteAction])
swipeAction.performsFirstActionWithFullSwipe = false
return swipeAction
}
我确实检查了其他问题,但没有一个问题可以解决.如有任何其他解决此问题需要了解的信息,请随时在此处发表评论.谢谢 :)