Swift 中的 ScrollView 和键盘

Question

我开始创建一个简单的 iOS 应用来执行一些操作。

但是当键盘出现时我遇到了一些问题，隐藏了我的一个文本字段。

我认为这是一个常见问题，我做了一些研究，但找不到任何解决我问题的方法。

我想使用 ScrollView 而不是为文本字段设置动画以使其可见。

Answer 1

在 ViewDidLoad 中，注册通知：

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name:UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name:UIResponder.keyboardWillHideNotification, object: nil)

添加以下观察者方法，当键盘出现时自动滚动。

@objc func keyboardWillShow(notification:NSNotification) {

    guard let userInfo = notification.userInfo else { return }
    var keyboardFrame:CGRect = (userInfo[UIResponder.keyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
    keyboardFrame = self.view.convert(keyboardFrame, from: nil)

    var contentInset:UIEdgeInsets = self.scrollView.contentInset
    contentInset.bottom = keyboardFrame.size.height + 20
    scrollView.contentInset = contentInset
}

@objc func keyboardWillHide(notification:NSNotification) {

    let contentInset:UIEdgeInsets = UIEdgeInsets.zero
    scrollView.contentInset = contentInset
}

Answer 2

swift 3 的最佳答案：

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

然后：

func keyboardWillShow(notification:NSNotification){
    //give room at the bottom of the scroll view, so it doesn't cover up anything the user needs to tap
    var userInfo = notification.userInfo!
    var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
    keyboardFrame = self.view.convert(keyboardFrame, from: nil)

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

func keyboardWillHide(notification:NSNotification){
    let contentInset:UIEdgeInsets = UIEdgeInsets.zero
    theScrollView.contentInset = contentInset
}

Answer 3

这是一个完整的解决方案，使用保护和简洁的代码。加上keyboardWillHide 中的正确代码，仅将bottom 重置为0。

@IBOutlet private weak var scrollView: UIScrollView!

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    registerNotifications()
}

override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)
    scrollView.contentInset.bottom = 0
}

private func registerNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}

@objc private func keyboardWillShow(notification: NSNotification){
    guard let keyboardFrame = notification.userInfo![UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
    scrollView.contentInset.bottom = view.convert(keyboardFrame.cgRectValue, from: nil).size.height
}

@objc private func keyboardWillHide(notification: NSNotification){
    scrollView.contentInset.bottom = 0
}

Answer 4

适用于 Swift 4.0

在 ViewDidLoad 中

// setup keyboard event
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)

添加以下观察者方法，当键盘出现时自动滚动。

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

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

@objc func keyboardWillHide(notification:NSNotification){

    let contentInset:UIEdgeInsets = UIEdgeInsets.zero
    ui_scrollView.contentInset = contentInset
}

Answer 5

contentInset 对我不起作用，因为我希望滚动视图一直向上移动到键盘上方。所以我用contentOffset:

func keyboardWillShow(notification:NSNotification) {
    guard let keyboardFrameValue = notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue else {
        return
    }
    let keyboardFrame = view.convert(keyboardFrameValue.cgRectValue, from: nil)
    scrollView.contentOffset = CGPoint(x:0, y:keyboardFrame.size.height)
}

func keyboardWillHide(notification:NSNotification) {
    scrollView.contentOffset = .zero
}

Answer 6

Swift 5仅在TextField被键盘隐藏时调整ScrollView（对于多个TextFields）

添加/删除观察者：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}

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

跟踪这些值，以便您回到原来的位置：

var scrollOffset : CGFloat = 0
var distance : CGFloat = 0

根据TextField位置调整ScrollView contentOffset：

@objc func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {

        var safeArea = self.view.frame
        safeArea.size.height += scrollView.contentOffset.y
        safeArea.size.height -= keyboardSize.height + (UIScreen.main.bounds.height*0.04) // Adjust buffer to your liking

        // determine which UIView was selected and if it is covered by keyboard

        let activeField: UIView? = [textFieldA, textViewB, textFieldC].first { $0.isFirstResponder }
        if let activeField = activeField {
            if safeArea.contains(CGPoint(x: 0, y: activeField.frame.maxY)) {
                print("No need to Scroll")
                return
            } else {
                distance = activeField.frame.maxY - safeArea.size.height
                scrollOffset = scrollView.contentOffset.y
                self.scrollView.setContentOffset(CGPoint(x: 0, y: scrollOffset + distance), animated: true)
            }
        }
        // prevent scrolling while typing

        scrollView.isScrollEnabled = false
    }
}
@objc func keyboardWillHide(notification: NSNotification) {
        if distance == 0 {
            return
        }
        // return to origin scrollOffset
        self.scrollView.setContentOffset(CGPoint(x: 0, y: scrollOffset), animated: true)
        scrollOffset = 0
        distance = 0
        scrollView.isScrollEnabled = true
}

确保第一次使用 [UIResponder.keyboardFrameEndUserInfoKey] 来获得正确的键盘高度。

Answer 7

来自 Sudheer Palchuri 的回答，已转换为 Swift 4。

在 ViewDidLoad 中，注册通知：

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

然后：

// MARK: - Keyboard Delegates
func textFieldShouldReturn(textField: UITextField) -> Bool {
    textField.resignFirstResponder()
    return true
}

@objc func keyboardWillShow(notification:NSNotification){

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

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

@objc func keyboardWillHide(notification:NSNotification){

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

Answer 8

阅读了你发给我的链接，我找到了让它工作的方法，谢谢！：

func textFieldDidBeginEditing(textField: UITextField) {            
    if (textField == //your_field) {
        scrollView.setContentOffset(CGPointMake(0, field_extra.center.y-280), animated: true)
        callAnimation()
        viewDidLayoutSubviews()
    }
}

func textFieldDidEndEditing(textField: UITextField) {    
    if (textField == //your_field){
        scrollView .setContentOffset(CGPointMake(0, 0), animated: true)
        viewDidLayoutSubviews()
    }
}

Answer 9

您可以通过滚动偏移为您的滚动视图设置动画以在键盘外观上以 UITextField 为中心（即，使您的文本字段成为第一响应者）。这里有一些很好的资源可以帮助你入门（这个网站上有很多）：

How programmatically move a UIScrollView to focus in a control above keyboard?

How to make a UIScrollView auto scroll when a UITextField becomes a first responder

此外，如果您只是在单元格中使用带有内容的 UITableView，当文本字段成为第一响应者时，UITableViewController 将自动滚动到文本字段单元格（尽管我不确定这是您想要做的） .

Answer 10

Swift 3 的答案，基于 Daniel Jones 提出的答案，但更安全（感谢守卫）、更简洁且具有一致的滚动指示器插图：

@objc private func keyboardWillBeShown(notification: NSNotification) {
    guard let keyboardFrameValue = notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue else { return }
    let keyboardFrame = view.convert(keyboardFrameValue.cgRectValue, from: nil)
    scrollView.contentInset.bottom = keyboardFrame.size.height
    scrollView.scrollIndicatorInsets = scrollView.contentInset
}

@objc private func keyboardWillBeHidden() {
    scrollView.contentInset = .zero
    scrollView.scrollIndicatorInsets = scrollView.contentInset
}

Answer 11

在 Swift4 中，只需添加以下扩展即可。

extension UIViewController {

   func setupViewResizerOnKeyboardShown() {
        NotificationCenter.default.addObserver(self,
                                           selector: #selector(self.keyboardWillShowForResizing),
                                           name: 
        Notification.Name.UIKeyboardWillShow,
                                           object: nil)
        NotificationCenter.default.addObserver(self,
                                           selector: #selector(self.keyboardWillHideForResizing),
                                           name: Notification.Name.UIKeyboardWillHide,
                                           object: nil)
        }

   @objc func keyboardWillShowForResizing(notification: Notification) {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue,
        let window = self.view.window?.frame {
        // We're not just minusing the kb height from the view height because
        // the view could already have been resized for the keyboard before
        self.view.frame = CGRect(x: self.view.frame.origin.x,
                                 y: self.view.frame.origin.y,
                                 width: self.view.frame.width,
                                 height: window.origin.y + window.height - keyboardSize.height)
      } else {
        debugPrint("We're showing the keyboard and either the keyboard size or window is nil: panic widely.")
      }
  }

   @objc func keyboardWillHideForResizing(notification: Notification) {
     if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
        let viewHeight = self.view.frame.height
        self.view.frame = CGRect(x: self.view.frame.origin.x,
                                 y: self.view.frame.origin.y,
                                 width: self.view.frame.width,
                                 height: viewHeight + keyboardSize.height)
    } else {
        debugPrint("We're about to hide the keyboard and the keyboard size is nil. Now is the rapture.")
    }
   }
 }

Answer 12

这是对上面发布的Zachary Probst 解决方案的改进。 我在他的解决方案中遇到了一些问题，并对其进行了修复并进行了一些改进。

这个版本不需要传入 UITextView 控件列表。它在当前视图中找到第一个响应者。它还处理视图层次结构中任何级别的 UITextView 控件。

我认为他的 safeArea 计算不太正确，scrollView.contentOffset.y 需要更改符号。如果不滚动它就不会显示。这个固定的增量滚动。这可能来自我所做的其他更改。

如果用户在键盘启动时跳转到其他 UITextViews，则此方法有效。

这是我用于一堆 ViewController 的基类。继承的 ViewController 只需要设置 UIScrollViewer 即可激活此代码行为。

class ThemeAwareViewController: UIViewController
{
    var scrollViewForKeyBoard: UIScrollView? = nil
    var saveOffsetForKeyBoard: CGPoint?
    
    func findViewThatIsFirstResponder(view: UIView) -> UIView?
    {
        if view.isFirstResponder {
            return view
        }

        for subView in view.subviews {
            if let hit = findViewThatIsFirstResponder(view: subView) {
                return hit
            }
        }

        return nil
    }
    
    @objc func keyboardWillShow(notification: NSNotification) {
        if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
            if let scrollView = scrollViewForKeyBoard {
                
                var safeArea = self.view.frame
                safeArea.size.height -= scrollView.contentOffset.y
                safeArea.size.height -= keyboardSize.height
                safeArea.size.height -= view.safeAreaInsets.bottom
                
                let activeField: UIView? = findViewThatIsFirstResponder(view: view)
                
                if let activeField = activeField {
                    // This line had me stumped for a while (I was passing in .frame)
                    let activeFrameInView = view.convert(activeField.bounds, from: activeField)
                    let distance = activeFrameInView.maxY - safeArea.size.height
                    if saveOffsetForKeyBoard == nil {
                        saveOffsetForKeyBoard = scrollView.contentOffset
                    }
                    scrollView.setContentOffset(CGPoint(x: 0, y: distance), animated: true)
                }
            }
        }
    }
    
    @objc func keyboardWillHide(notification: NSNotification) {
        guard let restoreOffset = saveOffsetForKeyBoard else {
            return
        }
        if let scrollView = scrollViewForKeyBoard {
            scrollView.setContentOffset(restoreOffset, animated: true)
            self.saveOffsetForKeyBoard = nil
        }
    }   
}

Answer 13

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

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

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

}

func keyboardWillShow(_ notification:Notification) {

    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardSize.height, 0)
    }
}
func keyboardWillHide(_ notification:Notification) {

    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        tableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
    }
}

Answer 14

如果有人正在为此解决方案寻找 Objective-C 代码：

- (void)keyboardWasShown:(NSNotification *)notification {
        NSDictionary* info = [notification userInfo];
        CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
        UIEdgeInsets contentInsets = baseScrollView.contentInset;
        contentInsets.bottom = kbSize.height;
        baseScrollView.contentInset = contentInsets;
    }

    - (void)keyboardWillBeHidden:(NSNotification *)notification {
        UIEdgeInsets contentInsets = UIEdgeInsetsZero;
        baseScrollView.contentInset = contentInsets;
        [baseScrollView endEditing:YES];
    }

Answer 15

在我的情况下

滚动视图 --> 表视图 --> TableViewCell

所以我必须获得相对于键盘框架的 y 位置，并检查键盘 y 位置和我的活动字段 y 位置是否相交

   @objc func keyboardWillShow(_ notification: Foundation.Notification) {

        var userInfo = notification.userInfo!
        var keyboardFrame:CGRect = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
        keyboardFrame = self.view.convert(keyboardFrame, from: nil)

        var contentInset:UIEdgeInsets = self.scrollView!.contentInset
        contentInset.bottom = keyboardFrame.size.height
        let loc = self.activeTextField?.convert(activeTextField!.bounds, to: self.view)

        if keyboardFrame.origin.y <  loc!.origin.y {
            self.scrollView?.contentOffset = CGPoint.init(x: (self.scrollView?.contentOffset.x)!, y: loc!.origin.y)
        }

        if self.scrollView?.contentInset.bottom == 0 {
            self.scrollView?.contentInset = contentInset
        }

    }