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")
}
}
如果你正在使用自动布局，我假设你已经设置了底部空间为Superview约束。如果是这种情况，您只需更新约束的值。这是你如何用一点动画来做到这一点。
func keyboardWasShown(notification: NSNotification) {
let info = notification.userInfo!
let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()
UIView.animateWithDuration(0.1, animations: { () -> Void in
self.bottomConstraint.constant = keyboardFrame.size.height + 20
})
}
添加硬编码的20只是为了将文本框弹出到键盘上方一点。否则键盘的上边距和文本框的下边距将会接触。
当键盘关闭时，将约束的值重置为原始值。
这是一个通用的解决方案，为所有的TextField
步骤,
1)创建一个由其他ViewController扩展的通用ViewController
override func viewDidLoad() {
super.viewDidLoad()
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 func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0 {
self.view.frame.origin.y -= getMoveableDistance(keyboarHeight: keyboardSize.height)
}
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y = 0
}
}
deinit {
NotificationCenter.default.removeObserver(self)
}
//get the distance to move up the main view for the focus textfiled
func getMoveableDistance(keyboarHeight : CGFloat) -> CGFloat{
var y:CGFloat = 0.0
if let activeTF = getSelectedTextField(){
var tfMaxY = activeTF.frame.maxY
var containerView = activeTF.superview!
while containerView.frame.maxY != self.view.frame.maxY{
let contViewFrm = containerView.convert(activeTF.frame, to: containerView.superview)
tfMaxY = tfMaxY + contViewFrm.minY
containerView = containerView.superview!
}
let keyboardMinY = self.view.frame.height - keyboarHeight
if tfMaxY > keyboardMinY{
y = (tfMaxY - keyboardMinY) + 10.0
}
}
return y
}
2)创建UIViewController和当前激活的TextField的扩展
//get active text field
扩展 UIViewController {
func getSelectedTextField（） -> UITextField？{
let totalTextFields = getTextFieldsInView(view: self.view)
for textField in totalTextFields{
if textField.isFirstResponder{
return textField
}
}
return nil
}
func getTextFieldsInView(view: UIView) -> [UITextField] {
var totalTextFields = [UITextField]()
for subview in view.subviews as [UIView] {
if let textField = subview as? UITextField {
totalTextFields += [textField]
} else {
totalTextFields += getTextFieldsInView(view: subview)
}
}
return totalTextFields
}
}
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)
}
}
如果你正在使用自动布局，我假设你已经设置了底部空间为Superview约束。如果是这种情况，您只需更新约束的值。这是你如何用一点动画来做到这一点。
func keyboardWasShown(notification: NSNotification) {
let info = notification.userInfo!
let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()
UIView.animateWithDuration(0.1, animations: { () -> Void in
self.bottomConstraint.constant = keyboardFrame.size.height + 20
})
}
添加硬编码的20只是为了将文本框弹出到键盘上方一点。否则键盘的上边距和文本框的下边距将会接触。
当键盘关闭时，将约束的值重置为原始值。
我创建了一个Swift 3协议来处理键盘的出现/消失
import UIKit
protocol KeyboardHandler: class {
var bottomConstraint: NSLayoutConstraint! { get set }
func keyboardWillShow(_ notification: Notification)
func keyboardWillHide(_ notification: Notification)
func startObservingKeyboardChanges()
func stopObservingKeyboardChanges()
}
extension KeyboardHandler where Self: UIViewController {
func startObservingKeyboardChanges() {
// NotificationCenter observers
NotificationCenter.default.addObserver(forName: NSNotification.Name.UIKeyboardWillShow, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillShow(notification)
}
// Deal with rotations
NotificationCenter.default.addObserver(forName: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillShow(notification)
}
// Deal with keyboard change (emoji, numerical, etc.)
NotificationCenter.default.addObserver(forName: NSNotification.Name.UITextInputCurrentInputModeDidChange, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillShow(notification)
}
NotificationCenter.default.addObserver(forName: NSNotification.Name.UIKeyboardWillHide, object: nil, queue: nil) { [weak self] notification in
self?.keyboardWillHide(notification)
}
}
func keyboardWillShow(_ notification: Notification) {
let verticalPadding: CGFloat = 20 // Padding between the bottom of the view and the top of the keyboard
guard let value = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue else { return }
let keyboardHeight = value.cgRectValue.height
// Here you could have more complex rules, like checking if the textField currently selected is actually covered by the keyboard, but that's out of this scope.
self.bottomConstraint.constant = keyboardHeight + verticalPadding
UIView.animate(withDuration: 0.1, animations: { () -> Void in
self.view.layoutIfNeeded()
})
}
func keyboardWillHide(_ notification: Notification) {
self.bottomConstraint.constant = 0
UIView.animate(withDuration: 0.1, animations: { () -> Void in
self.view.layoutIfNeeded()
})
}
func stopObservingKeyboardChanges() {
NotificationCenter.default.removeObserver(self)
}
}
然后，要在UIViewController中实现它，执行以下操作:
let the viewController conform to this protocol :
class FormMailVC: UIViewControlle, KeyboardHandler {
start observing keyboard changes in viewWillAppear:
// MARK: - View controller life cycle
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
startObservingKeyboardChanges()
}
stop observing keyboard changes in viewWillDisappear:
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
stopObservingKeyboardChanges()
}
create an IBOutlet for the bottom constraint from the storyboard:
// NSLayoutConstraints
@IBOutlet weak var bottomConstraint: NSLayoutConstraint!
(I recommend having all of your UI embedded inside a "contentView", and linking to this property the bottom constraint from this contentView to the bottom layout guide)
change the constraint priority of the top constraint to 250 (low)
这是为了让整个内容视图在键盘出现时向上滑动。
优先级必须低于子视图中的任何其他约束优先级，包括内容拥抱优先级/内容抗压缩优先级。
确保你的自动布局有足够的约束来决定contentView应该如何滑动。
你可能需要添加一个“大于等于”的约束:
给你!
