我使用Swift与iOS编程，我使用这段代码来移动UITextField，但它不起作用。我正确地调用了函数keyboardWillShow，但是文本字段没有移动。我正在使用自动布局。
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
}
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self);
}
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
//let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
var frame = self.ChatField.frame
frame.origin.y = frame.origin.y - keyboardSize.height + 167
self.chatField.frame = frame
println("asdasd")
}
}
Well, I think i might be too late but i found another simple version of Saqib's answer. I'm using Autolayout with constraints. I have a small view inside of another main view with username and password fields. Instead of changing the y coordinate of the view i'm saving the original constraint value in a variable and changing the constraint's constant to some value and again after the keyboard dismisses, i'm setting up the constraint to original one. This way it avoids the problem Saqib's answer has, (The view keeps on moving up and does not stop). Below is my code...
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
self.originalConstraint = self.centerYConstraint.constant
}
func keyboardWillShow(sender: NSNotification) {
self.centerYConstraint.constant += 30
}
func keyboardWillHide(sender: NSNotification) {
self.centerYConstraint.constant = self.originalConstraint
}
编辑:我推荐一个更简单、更干净的解决方案。只需将底部间距约束的类更改为KeyboardLayoutConstraint。它会自动展开到键盘高度。
这是一个改进版的@JosephLord的回答。
在iOS 8.3 iPad模拟器上测试，Portrait。Xcode6.3 beta4，我发现他的答案不工作时，键盘隐藏，因为UIKeyboardFrameEndUserInfoKey是“NSRect:{{0, 1024}，{768, 264}}”;高度不为0。
这回到使用传统的UIKeyboardWillShowNotification和UIKeyboardWillHideNotification来更好地判断键盘何时隐藏，而不是依赖于结束帧的高度。UIKeyboardWillShowNotification也会在键盘帧改变时发送，所以它应该覆盖所有的用例。
// You have to set this up in storyboard first!.
// It's a vertical spacing constraint between view and bottom of superview.
@IBOutlet weak var bottomSpacingConstraint: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardNotification:"), name:UIKeyboardWillShowNotification, object: nil);
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardNotification:"), name:UIKeyboardWillHideNotification, object: nil);
}
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self)
}
func keyboardNotification(notification: NSNotification) {
let isShowing = notification.name == UIKeyboardWillShowNotification
if let userInfo = notification.userInfo {
let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.CGRectValue()
let endFrameHeight = endFrame?.size.height ?? 0.0
let duration:NSTimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
let animationCurveRaw = animationCurveRawNSN?.unsignedLongValue ?? UIViewAnimationOptions.CurveEaseInOut.rawValue
let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
self.bottomSpacingConstraint?.constant = isShowing ? endFrameHeight : 0.0
UIView.animateWithDuration(duration,
delay: NSTimeInterval(0),
options: animationCurve,
animations: { self.view.layoutIfNeeded() },
completion: nil)
}
}
对于任何不使用故事板设置布局约束的人。这是一种纯粹的编程方式，让它在Swift 5上工作:
在viewController中定义一个空约束。在这种情况下，我正在构建一个聊天应用程序，在屏幕的最底部有一个包含文本视图的UIView。
var discussionsMessageBoxBottomAnchor: NSLayoutConstraint = NSLayoutConstraint()
在viewDidLoad中为最底部的视图添加约束。在本例中是discussionsMessageBox。另外，为键盘事件添加监听器。
为了正确地初始化约束，您需要首先添加子视图，然后定义约束。
NotificationCenter.default.addObserver(self,
selector: #selector(self.keyboardNotification(notification:)),
name: NSNotification.Name.UIKeyboardWillChangeFrame,
object: nil)
view.addSubview(discussionsMessageBox)
if #available(iOS 11.0, *) {
discussionsMessageBoxBottomAnchor = discussionsMessageBox.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: 0)
} else {
// Fallback on earlier versions
discussionsMessageBoxBottomAnchor = discussionsMessageBox.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0)
}
NSLayoutConstraint.activate([ discussionsMessageBoxBottomAnchor ])
定义deinit。
deinit {
NotificationCenter.default.removeObserver(self)
}
接下来添加@JosephLord定义的代码，并对偏移量进行修正。
extension DiscussionsViewController {
@objc func keyboardNotification(notification: NSNotification) {
guard let userInfo = notification.userInfo else { return }
let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
let endFrameY = endFrame?.origin.y ?? 0
let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIView.AnimationOptions.curveEaseInOut.rawValue
let animationCurve:UIView.AnimationOptions = UIView.AnimationOptions(rawValue: animationCurveRaw)
if endFrameY >= UIScreen.main.bounds.size.height {
self.discussionsMessageBoxBottomAnchor.constant = 0.0
} else {
//Changed line
self.discussionsMessageBoxBottomAnchor.constant = -1 * (endFrame?.size.height ?? 0.0)
}
UIView.animate(
withDuration: duration,
delay: TimeInterval(0),
options: animationCurve,
animations: { self.view.layoutIfNeeded() },
completion: nil)
}
}
一个简单的解决方案是移动视图与键盘高度常数。
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
}
@objc func keyboardWillShow(sender: NSNotification) {
self.view.frame.origin.y = -150 // Move view 150 points upward
}
@objc func keyboardWillHide(sender: NSNotification) {
self.view.frame.origin.y = 0 // Move view to original position
}
斯威夫特5:
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(sender:)), name: UIResponder.keyboardWillShowNotification, object: nil);
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(sender:)), name: UIResponder.keyboardWillHideNotification, object: nil);
我使用的Swift 4解决方案需要键盘大小。将serverStatusStackView替换为任何你关心的视图，例如:self.view:
deinit {
NotificationCenter.default.removeObserver(self)
}
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
serverStatusStackView.frame.origin.y = keyboardSize.height * 2 - serverStatusStackView.frame.height
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
serverStatusStackView.frame.origin.y += keyboardSize.height
}
}
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
