当键盘出现时移动按钮 Swift

Question

当键盘出现时移动按钮 Swift

8

在UIViewController中，我有几个文本字段和一个按钮在UIViewController的底部。对于按钮，我设置了一个常量为0的底部约束。然后，我从底部约束到UIViewController创建了一个outlet。

当我运行我的代码时，按钮不会向上移动。我在stackoverflow上看到了建议，说我应该添加UIScrollView，但这意味着我必须删除UIViewController上的所有对象，放置UIScrollView，然后再将我的对象放回到UIVIewController上。

@IBOutlet weak var bottomConstraint: NSLayoutConstraint!

// When tapping outside of the keyboard, close the keyboard down
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    self.view.endEditing(true)
}

// Stop Editing on Return Key Tap. textField parameter refers to any textfield within the view
func textFieldShouldReturn(textField: UITextField) -> Bool {
    textField.resignFirstResponder()
    return true
}

// When keyboard is about to show assign the height of the keyboard to bottomConstraint.constant of our button so that it will move up
func keyboardWillShow(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        if let keyboardSize: CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
            bottomConstraint.constant = keyboardSize.size.height
            view.setNeedsLayout()
        }
    }
}

// When keyboard is hidden, move the button to the bottom of the view
func keyboardWillHide(notification: NSNotification) {
    bottomConstraint.constant = 0.0
    view.setNeedsLayout()
}

- bibscy

5个回答

5

为了补充Ryan上面的答案，这可以完全使用自动布局来完成，无需使用框架和CGRect。

Swift 5

在您的视图中，按照通常的方式约束按钮，但添加一个约束的引用，以便在键盘隐藏/显示时进行修改：

var bottomButtonConstraint = NSLayoutConstraint()

bottomButtonConstraint = yourButton.bottomAnchor.constraint(equalTo: safeAreaLayoutGuide.bottomAnchor, constant: -12)
bottomButtonConstraint.isActive = true

在您的视图控制器中的 viewDidLoad() 函数内：

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

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

在你的ViewController中：

@objc private func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        self.yourCustomView.bottomButtonConstraint.constant -= keyboardSize.height
    }
}

@objc private func keyboardWillHide(notification: NSNotification) {
    self.yourCustomView.bottomButtonConstraint.constant = -12
}

- Justin Vallely

safeArea 未定义 :/ - Rami Alloush

1

错别字。请尝试使用 safeAreaLayoutGuide。 - Justin Vallely

view.safeAreaLayoutGuide.bottomAnchor - iMinion

3

您需要在viewDidLoad中添加观察者来调用您的函数：

NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillShow), name: UIKeyboardDidShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillHide), name: UIKeyboardDidHideNotification, object: nil)

- Klevison

我添加了观察者，它起作用了。然而，@Ryan说我的实现会因为不同的iPhone屏幕尺寸而暴露出意外的行为。他提出了一种方法，但它没有起作用。按钮不随键盘升起，键盘在点击外部时不再放弃，当在键盘外部点击时，我现在创建的编程按钮不再显示，在iPhone 6上，按钮固定在屏幕底部，但在其他屏幕上看起来不同，nextButton.frame = CGRectMake(0, 620, 375, 50)。你能帮忙吗？ - bibscy

0

考虑使用这个pod：https://cocoapods.org/pods/IQKeyboardManager 在AppDelegate.swift中，只需导入IQKeyboardManagerSwift框架并启用IQKeyboardManager。

import IQKeyboardManagerSwift

@UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

  IQKeyboardManager.shared.enable = true

  return true
}

}

- Nedim Karavdic

IQKeyboardManager会在文本框被键盘遮挡时更新文本框内容。但它并没有回答这个问题。 - Ankur Lahiry

0

我知道我来晚了一点，但由于上一个回答是在大约2年前，我认为我可以为这个问题提供更多的价值。我的示例适用于Swift 5.5+，但较低版本也应该可以使用。

在我的场景中，我需要一种更通用、可配置的解决方案，它可以让我在项目中的任何UIViewController类中移动视图并控制间距。

以下是使其工作所需的步骤：

第一步：

为您的视图底部约束创建outlet，并为键盘和源视图定义自定义间距：

@IBOutlet weak var <<yourViewName>>BottomConstraint: NSLayoutConstraint! // Your view's bottom constraint, that should be connected to safe/area or superview

private let <<yourViewName>>BottomSpacing: CGFloat = 56 // Spacing between view and safe area/superview when keyboard is hidden
private let <<yourViewName>>KeyboardSpacing: CGFloat = 22 // Spacing between active keyboard and your view

第二步：

在我们的视图控制器中注册观察者，以跟踪键盘的显示/隐藏（您可以根据需要在viewDidLoad或init中调用此方法）。请注意，在旧版本的Swift中，您必须手动删除观察者，例如在deinit中。

private func addKeyboardObservers() {
    // Notifications for when the keyboard show/hides
    NotificationCenter.default.addObserver(self,
                                           selector: #selector(self.keyboardWillShow),
                                           name: UIResponder.keyboardWillShowNotification,
                                           object: nil)
    NotificationCenter.default.addObserver(self,
                                           selector: #selector(self.keyboardWillHide),
                                           name: UIResponder.keyboardWillHideNotification,
                                           object: nil)
}

第三步：

将以下代码添加到您的UIViewController类中。这段代码将作为NotificationCenter观察者的结果被调用：

@objc private func keyboardWillShow(_ notification: NSNotification) {
    moveViewWithKeyboard(notification: notification,
                         keyboardWillShow: true,
                         viewBottomConstraint: <<yourViewName>>BottomConstraint,
                         activeKeyboardToViewSpacing: <<yourViewName>>KeyboardSpacing,
                         hiddenKeyboardToViewSpacing: <<yourViewName>>BottomSpacing)
}

@objc private func keyboardWillHide(_ notification: NSNotification) {
    moveViewWithKeyboard(notification: notification,
                         keyboardWillShow: false,
                         viewBottomConstraint: <<yourViewName>>BottomConstraint,
                         activeKeyboardToViewSpacing: <<yourViewName>>KeyboardSpacing,
                         hiddenKeyboardToViewSpacing: <<yourViewName>>BottomSpacing)
}

第四步：

拼图的最后一部分是一个方法，它获取键盘大小，计算间距并相应地移动视图。

通常，在我的项目中，我有一个名为UIViewController+Keyboard.swift的文件，其中包含这段代码作为extension到UIViewController。您还可以添加其他与键盘管理相关的代码，例如在用户点击周围时隐藏键盘，如下面的示例所示：

extension UIViewController {

func hideKeyboardWhenTappedAround() {
    let tap = UITapGestureRecognizer(target: self, action: #selector(UIViewController.dismissKeyboard))
    tap.cancelsTouchesInView = false
    view.addGestureRecognizer(tap)
}

@objc
func dismissKeyboard() {
    view.endEditing(true)
}

func moveViewWithKeyboard(notification: NSNotification,
                          keyboardWillShow: Bool,
                          viewBottomConstraint: NSLayoutConstraint,
                          activeKeyboardToViewSpacing: CGFloat,
                          hiddenKeyboardToViewSpacing: CGFloat) {
    
    guard let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else { return }
    let keyboardHeight = keyboardSize.height
    let keyboardAnimationDuration = notification.userInfo![UIResponder.keyboardAnimationDurationUserInfoKey] as! Double
    let keyboardAnimationCurve = UIView.AnimationCurve(rawValue: notification.userInfo![UIResponder.keyboardAnimationCurveUserInfoKey] as! Int)!
    
    // Modifying spacing constants
    if keyboardWillShow {
        let safeAreaExists = self.view?.window?.safeAreaInsets.bottom != 0
        // Default value in case something goes wrong with bottom spacings
        let bottomConstant: CGFloat = 20
        viewBottomConstraint.constant = keyboardHeight + (safeAreaExists ? 0 : bottomConstant) + activeKeyboardToViewSpacing
    } else {
        viewBottomConstraint.constant = hiddenKeyboardToViewSpacing
    }
    
    // Animating the view the same way the keyboard animates
    let animator = UIViewPropertyAnimator(duration: keyboardAnimationDuration, curve: keyboardAnimationCurve) { [weak self] in
        self?.view.layoutIfNeeded()
    }
    
    animator.startAnimation()
} }

实施所有这些步骤后，您应该获得所需的可重用行为和可配置的间距。希望对您有所帮助！

- Taras Tomchuk

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Ryan Cocuzzo · Accepted Answer

解决这个问题的典型方法是使用以下代码将键盘移动：

在 ViewController 类中：

  func keyboardWillShow(notification: NSNotification) {

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

                self.view.frame.origin.y += height
            }

        }

    }

    func keyboardWillHide(notification: NSNotification) {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
            if view.frame.origin.y != 0 {
                let height = keyboardSize.height
                self.view.frame.origin.y -= height
            }

        }
    }

在ViewDidLoad方法中：

  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)

请注意： 你尝试解决问题的方法是不被允许的。在上述代码中，如果你将view改为你的按钮变量名，按钮会弹起然后掉落。这是因为自动布局和编程布局不能同时使用，只能选择其中一种。你需要通过编程方式创建该按钮（使用CGRect），然后使用上述代码仅移动该按钮以响应键盘按下事件（通过将view更改为你的按钮变量名）。

   func keyboardWillShow(notification: NSNotification) {

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

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

要在程序中创建按钮，您需要使用类似于以下代码的代码：

myButton.frame = CGRect(...)