ios - 当键盘出现时移动 View 并将其呈现在 ScrollView 中。 swift 3

Question

SO 上有几个类似的问题，但未解决以下问题。

我正在开发一个简单的登录 View ，其中只有 2 个用于电子邮件和密码的文本字段。最好的用户体验是当用户点击其中一个文本字段时，键盘弹出， View 向上移动，同时变成 ScrollView 。这样，用户仍然可以看到屏幕上还有哪些其他 UI 元素。用户还应该能够通过向下滑动来隐藏键盘。(Instagram 和其他大佬已经实现了这个)

我能够构建一个没有 ScrollView 的 View ，并通过 resignFirstResponder 关闭键盘:

class SignInVC: UIViewController, UITextFieldDelegate {

@IBOutlet weak var pwdField: UITextField!
@IBOutlet weak var emailField: UITextField!
@IBOutlet weak var scrollView: UIScrollView!

var keyboardDismissTapGesture: UIGestureRecognizer?

func dismissKeyboard(sender: AnyObject) {
    pwdField?.resignFirstResponder()
    emailField?.resignFirstResponder()
}

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

override func viewDidAppear(_ animated: Bool) {

    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

func keyboardWillShow(notification: NSNotification) {

    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        if self.view.frame.origin.y == 0{
            self.view.frame.origin.y -= keyboardSize.height  
        }
    }

    if keyboardDismissTapGesture == nil
    {
        keyboardDismissTapGesture = UITapGestureRecognizer(target: self,
                                                           action: #selector(self.dismissKeyboard))
        self.view.addGestureRecognizer(keyboardDismissTapGesture!)
    }
}

func keyboardWillHide(notification: NSNotification) {

    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        if self.view.frame.origin.y != 0{
            self.view.frame.origin.y += keyboardSize.height
        }
    }

    if keyboardDismissTapGesture != nil
    {
        self.view.removeGestureRecognizer(keyboardDismissTapGesture!)
        keyboardDismissTapGesture = nil
    }
}

override func viewWillDisappear(_ animated: Bool) {
    NotificationCenter.default.removeObserver(self)

    super.viewWillDisappear(animated)
}

我正在尝试使用 scrollView.contentSize 尝试移动它的原点: scrollView.frame.origin.y -= keyboardSize.height

或其内容大小: scrollView.contentSize = CGSize(宽度:self.view.frame.width，高度:self.view.frame.height - keyboardSize.height)

但没有任何效果。

关于键盘向下滑动的能力，有信息说在 scrollView 的属性检查器中，我可以将“Keyboard”属性更改为“Dismiss Interactively”。没用。

Answer 1

//声明一个 uitextfield 来保存您的事件文本字段

var activeTextField:UITextField!

//在 vi​​ewdidload 中添加键盘关闭点击手势

override func viewDidLoad() {
    super.viewDidLoad()   
 keyboardDismissTapGesture = UITapGestureRecognizer(target: self,                                                           action:      #selector(self.dismissKeyboard))     
}

//在文本字段中设置事件文本字段确实开始委托(delegate)

func textFieldDidBeginEditing(textField: UITextField) {
activeTextField  = textField

    }

func textFieldDidEndEditing(textField: UITextField) {

  activeTextField  = nil
}

//关闭 activeTextField 的键盘

func dismissKeyboard(){
   activeTextField.resignFirstResponder()
}

//当键盘显示时调整 ScrollView 内容大小

func keyboardWillShow(notification:NSNotification){

    var userInfo = notification.userInfo!
    var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue()
    keyboardFrame = self.view.convertRect(keyboardFrame, fromView: nil)

    var contentInset:UIEdgeInsets = self.scrollView.contentInset
    contentInset.bottom = keyboardFrame.size.height
    self.scrollView.contentInset = contentInset
}

//键盘消失时重置 ScrollView

func keyboardWillHide(notification:NSNotification){

    let contentInset:UIEdgeInsets = UIEdgeInsetsZero
    self.scrollView.contentInset = contentInset
}