UIScrollView 在键盘上向上滚动答案

【问题标题】：UIScrollView scroll up on KeyboardUIScrollView 在键盘上向上滚动
【发布时间】：2017-08-11 11:10:08
【问题描述】：

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 和底部的 TextView。我想要的是在 textfield 或 Textview 开始编辑时向上滚动。

我尝试了什么：

在客户方法

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

我正在调用这个方法父视图。

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，但不适用于 UITextView。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。

【问题讨论】：

你可以使用 contentoffset 来滚动滚动视图。
使用github.com/hackiftekhar/IQKeyboardManager，它会自动检测 textField 或 textView 并相应地管理所有键盘处理。
@ZahidShabbir : 在 textview 的情况下，scrollview 没有向上滚动或滚动一点？
@zahidshabbir : 你试过使用 contentOffset 吗？
@zahidshabbir 请看下面的答案。

标签： ios ipad uiscrollview keyboard uitextview

【解决方案1】：

用下面的函数替换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)

希望它会有所帮助。快乐编码！

【讨论】：

【解决方案2】：

演示链接：https://github.com/harshilkotecha/UIScrollViewWhenKeyboardAppearInSwift3

当你有多个文本视图时，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中

// 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)
    }

【讨论】：

【解决方案3】：

斯威夫特 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.

【讨论】：