UIScrollView 在键盘上向上滚动

Question

问题陈述：我有 UIView 的 Nib 文件包含 UIScrollview，在滚动视图中我有几个 TextFields 和一个位于底部的 TextView。我想要的是在 textfield 或 Textview 开始编辑时向上滚动。

我试过的：

在客户方法中

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)

我正在调用此方法父视图。

通知处理：

func keyboardWasShown(notification: NSNotification)
{
    var userInfo = notification.userInfo!
    var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
    keyboardFrame = self.convert(keyboardFrame, from: nil)

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

这对 UITextFields 非常有效，但对 UITextView 无效。知道错误在哪里。

PS: 我也设置了UITextField和UITextView的Delegates

任何帮助将不胜感激。

Answer 1

用以下函数替换 keyboardWasShown 函数：

 func keyboardWasShown(notification: NSNotification)
{
    var userInfo = notification.userInfo!
    var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
    keyboardFrame = self.convert(keyboardFrame, from: nil)
    self.mainScroll.contentOffset = CGPoint(x: 0, y: keyboardFrame.size.height - Any number that fits your need.)
}

在 keyBoardWillHide 中：

self.mainScroll.contentOffset = CGPoint(x: 0, y: 0)

希望对您有所帮助。快乐编码！

Answer 2

演示 link：https://github.com/harshilkotecha/UIScrollViewWhenKeyboardAppearInSwift3

当你有多个 textview 时，它是如此困难，所以最好的解决方案 ->

第 1 步：添加 UITextFieldDelegate

class ScrollViewController: UIViewController,UITextFieldDelegate {

第 2 步：创建新的 IBOutlet 但不连接任何文本字段

//  get current text box when user Begin editing
    @IBOutlet weak var activeTextField: UITextField?

第 3 步：当用户关注文本字段对象时编写这两个方法传递引用并存储在 activeTextField

// get current text field
    func textFieldDidBeginEditing(_ textField: UITextField)
    {
        activeTextField=textField;
    }
    func textFieldDidEndEditing(_ textField: UITextField)
    {
        activeTextField=nil;
    }

第 5 步：在 viewdidload 中设置通知 setNotificationKeyboard

override func viewWillAppear(_ animated: Bool) {
        // call method for keyboard notification
        self.setNotificationKeyboard()
    }

    // Notification when keyboard show
    func setNotificationKeyboard ()  {
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(notification:)), name: .UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(notification:)), name: .UIKeyboardWillHide, object: nil)
    }

第 6 步：隐藏和显示键盘的两种方法

func keyboardWasShown(notification: NSNotification)
    {
        var info = notification.userInfo!
        let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
        let contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize!.height+10, 0.0)
        self.scrollView.contentInset = contentInsets
        self.scrollView.scrollIndicatorInsets = contentInsets
        var aRect : CGRect = self.view.frame
        aRect.size.height -= keyboardSize!.height
        if let activeField = self.activeTextField
        {
            if (!aRect.contains(activeField.frame.origin))
            {
                self.scrollView.scrollRectToVisible(activeField.frame, animated: true)
            }
        }
    }
    // when keyboard hide reduce height of scroll view
    func keyboardWillBeHidden(notification: NSNotification){
        let contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0,0.0, 0.0)
        self.scrollView.contentInset = contentInsets
        self.scrollView.scrollIndicatorInsets = contentInsets
        self.view.endEditing(true)
    }

Answer 3

Swift 5

NotificationCenter.default.addObserver(self, selector: #selector(keyboardNotification), name: UIResponder.keyboardDidChangeFrameNotification, object: nil)


@objc func keyboardNotification(_ notification: Notification) {
        if let userInfo = (notification as NSNotification).userInfo {
            let endFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
            let duration:TimeInterval = (userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
            let animationCurveRawNSN = userInfo[UIResponder.keyboardAnimationCurveUserInfoKey] as? NSNumber
            let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIView.AnimationOptions().rawValue
            let animationCurve:UIView.AnimationOptions = UIView.AnimationOptions(rawValue: animationCurveRaw)
            if (endFrame?.origin.y)! >= UIScreen.main.bounds.size.height {
                scrollViewBottomConstraint?.constant = 0
            } else {
                if tabBarController?.tabBar.frame == nil {
                    return
                }
                scrollViewBottomConstraint?.constant = endFrame!.size.height - (tabBarController?.tabBar.frame.height)!
                let bottomOffset = CGPoint(x: 0, y: 0)
                scrollView.setContentOffset(bottomOffset, animated: true)
            }
            UIView.animate(withDuration: duration, delay: 0, options: animationCurve, animations: { self.view.layoutIfNeeded() }, completion: nil)
        }
    }

用法：

1.connect the scrollView outlet to your controller and set its name to 'scrollView'
2.connect the scrollView bottom constraint to your controller & set its name to 'scrollViewBottomConstraint'
3.put the notification observer to your ViewDidLoad function.

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