Swift：ScrollRectToVisible无效

Question

在尝试了这里发布的大多数解决方案之后，我仍然无法移动文本字段以在滚动视图中显示在键盘上方。

这些是我从Stackoverflow解决方案中获得的链接： Link 1 Link 2 Link 3

我正在注册屏幕上工作，当屏幕显示时，键盘后面有一个字段。

这是我的代码：

class SignUpViewController: UIViewController, UITextFieldDelegate, UIScrollViewDelegate, UIPopoverPresentationControllerDelegate {

@IBOutlet var firstNameTextField: UITextField!
@IBOutlet var lastNameTextField: UITextField!
@IBOutlet var phoneNumberTextField: UITextField!
@IBOutlet var emailTextField: UITextField!
@IBOutlet var submitButton: UIButton!
@IBOutlet var professionButton: UIButton!

var scrollView: UIScrollView?
var activeTextField:UITextField? = UITextField()

override func viewDidLoad() {
    super.viewDidLoad()

    let notificationCenter = NSNotificationCenter.defaultCenter()

    notificationCenter.addObserver(self, selector: #selector(SignUpViewController.keyboardWasShown(_:)), name: UIKeyboardWillShowNotification, object: nil)
    notificationCenter.addObserver(self, selector: #selector(SignUpViewController.keyboardWillBeHidden(_:)), name: UIKeyboardWillHideNotification, object: nil)
    scrollView = UIScrollView(frame: CGRect(x: 0, y: 0, width: self.view.frame.size.width, height: self.view.frame.size.height))
    scrollView!.contentSize = CGSizeMake(self.view.frame.width, self.view.frame.height)

    defaultSettings()
}

func defaultSettings() {
    self.firstNameTextField.delegate = self
    self.lastNameTextField.delegate = self
    self.emailTextField.delegate = self
    self.phoneNumberTextField.delegate = self
}

func deregisterFromKeyboardNotifications()
{
    //Removing notifies on keyboard appearing
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}

func keyboardWasShown(notification: NSNotification)
{
    //Need to calculate keyboard exact size due to Apple suggestions
    //self.scrollView!.scrollEnabled = true
    var info : NSDictionary = notification.userInfo!
    var keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
    var contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize!.height, 0.0)

    self.scrollView!.contentInset = contentInsets
    self.scrollView!.scrollIndicatorInsets = contentInsets

    var aRect : CGRect = self.view.frame
    aRect.size.height -= keyboardSize!.height
    if (!CGRectContainsPoint(aRect, activeTextField!.frame.origin))
    {
//            print(activeTextField?.frame)
//            var scrollPoint = CGPointMake(0.0, activeTextField!.frame.origin.y - (keyboardSize!.height-15))
        self.scrollView!.scrollRectToVisible((activeTextField?.frame)!, animated: true)
        //self.scrollView?.setContentOffset(scrollPoint, animated: true)
    }
}


func keyboardWillBeHidden(notification: NSNotification)
{
    //Once keyboard disappears, restore original positions
    //var info : NSDictionary = notification.userInfo!
    //var keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
    var contentInsets : UIEdgeInsets = UIEdgeInsetsZero
    self.scrollView!.contentInset = contentInsets
    self.scrollView!.scrollIndicatorInsets = contentInsets
//        self.view.endEditing(true)
//        self.scrollView!.scrollEnabled = false

}

func textFieldDidBeginEditing(textField: UITextField)
{
    activeTextField = textField
}

func textFieldDidEndEditing(textField: UITextField)
{
    activeTextField = nil
}

正如您所看到的，我已尝试使用frame的scrollRectToVisible和使用Point的setContentOffset。两者都没有奏效。而代码选择emailTextField作为隐藏文本字段。

Answer 1

我也遇到了和你一样的问题，我不知道你是否成功并找到了解决方案，但我最后使用了setContentOffset函数而不是scrollRectToVisible而且它有效。

Swift 3.x示例：

function HandleClick(e) {
    e.preventDefault();
    ...
}

Answer 2

您还应该将scrollView委托设置为：

self.scrollView.delegate = self as! UIScrollViewDelegate

ScrollView委托方法与此配合使用。

Answer 3

SWIFT 4 尝试

scrollView.scrollRectToVisible(myElementView.frame, animated: true)

其中myElementView可以是任何元素