我有一个应用，它在视图的下半部分有一个文本框。 这意味着当我在文本框中输入时，键盘会覆盖文本框。
我如何在打字时向上移动视图，这样我就可以看到我键入的内容，然后在键盘消失时将它移回原来的位置?
我到处都看了，但所有的解似乎都在Obj-C中，我还不能完全转换。
任何帮助都将不胜感激。
当前回答
对于黑屏错误(Swift 4和4.2)。
我解决了黑屏的问题。在验证方案中，敲击后键盘高度变化，导致黑屏。
必须使用UIKeyboardFrameEndUserInfoKey而不是UIKeyboardFrameBeginUserInfoKey
var isKeyboardAppear = false
override func viewDidLoad() {
super.viewDidLoad()
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)
}
@objc func keyboardWillShow(notification: NSNotification) {
if !isKeyboardAppear {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0{
self.view.frame.origin.y -= keyboardSize.height
}
}
isKeyboardAppear = true
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if isKeyboardAppear {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0{
self.view.frame.origin.y += keyboardSize.height
}
}
isKeyboardAppear = false
}
}
其他回答
在这个线程中，一个流行的答案使用了以下代码:
func keyboardWillShow(sender: NSNotification) {
self.view.frame.origin.y -= 150
}
func keyboardWillHide(sender: NSNotification) {
self.view.frame.origin.y += 150
}
用一个静态量来抵消你的视图有一个明显的问题。它在一个设备上看起来很好，但在任何其他尺寸配置上看起来都很糟糕。您需要获取键盘高度并将其用作偏移值。
下面是一种适用于所有设备的解决方案，它可以处理用户在输入时隐藏预测文本字段的边缘情况。
解决方案
下面需要注意的是，我们将self.view.window作为对象参数传入。这将为我们提供来自键盘的数据，比如它的高度!
@IBOutlet weak var messageField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: self.view.window)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: self.view.window)
}
func keyboardWillHide(sender: NSNotification) {
let userInfo: [NSObject : AnyObject] = sender.userInfo!
let keyboardSize: CGSize = userInfo[UIKeyboardFrameBeginUserInfoKey]!.CGRectValue.size
self.view.frame.origin.y += keyboardSize.height
}
我们将使它在所有设备上看起来都很漂亮，并处理用户添加或删除预测文本字段的情况。
func keyboardWillShow(sender: NSNotification) {
let userInfo: [NSObject : AnyObject] = sender.userInfo!
let keyboardSize: CGSize = userInfo[UIKeyboardFrameBeginUserInfoKey]!.CGRectValue.size
let offset: CGSize = userInfo[UIKeyboardFrameEndUserInfoKey]!.CGRectValue.size
if keyboardSize.height == offset.height {
UIView.animateWithDuration(0.1, animations: { () -> Void in
self.view.frame.origin.y -= keyboardSize.height
})
} else {
UIView.animateWithDuration(0.1, animations: { () -> Void in
self.view.frame.origin.y += keyboardSize.height - offset.height
})
}
}
删除观察者
不要忘记在离开视图之前删除您的观察器，以防止传输不必要的消息。
override func viewWillDisappear(animated: Bool) {
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: self.view.window)
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: self.view.window)
}
根据评论中的问题更新:
如果你有两个或更多的文本字段，你可以检查你的view.frame.origin.y是否为零。
func keyboardWillShow(sender: NSNotification) {
let userInfo: [NSObject : AnyObject] = sender.userInfo!
let keyboardSize: CGSize = userInfo[UIKeyboardFrameBeginUserInfoKey]!.CGRectValue.size
let offset: CGSize = userInfo[UIKeyboardFrameEndUserInfoKey]!.CGRectValue.size
if keyboardSize.height == offset.height {
if self.view.frame.origin.y == 0 {
UIView.animateWithDuration(0.1, animations: { () -> Void in
self.view.frame.origin.y -= keyboardSize.height
})
}
} else {
UIView.animateWithDuration(0.1, animations: { () -> Void in
self.view.frame.origin.y += keyboardSize.height - offset.height
})
}
print(self.view.frame.origin.y)
}
最简单的方法，甚至不需要任何代码:
下载KeyboardLayoutConstraint.swift并将文件添加(拖放)到你的项目中，如果你还没有使用Spring动画框架的话。 在你的故事板中，为视图或文本字段创建一个底部约束，选择约束(双击它)，在标识检查器中，将其类从NSLayoutConstraint更改为KeyboardLayoutConstraint。 完成了!
物体会随着键盘同步自动移动。
这个实现(Swift 4)将给你的行为最接近Android的默认行为。Ie:当活动文本域在键盘下时，将视图向上移动，当用户切换到另一个视图时，无需关闭键盘。记住调用settextfielddelegate()。
public class DelegateProxy: NSObject, UITextFieldDelegate {
private static let instance = DelegateProxies()
weak var activeTextField: UITextField?
var offset: CGFloat = 0
weak var vc: UIViewController?
var keyboardHeight: CGFloat = 0
public static func getDelegate(root: UIViewController) -> DelegateProxies {
instance.vc = root
return instance
}
public static func getDelegate() -> DelegateProxies {
return instance
}
public func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
public func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
self.activeTextField = textField
let globalPointY: CGFloat = (textField.superview?.convert(textField.frame.origin, to: nil).y ?? CGFloat(0)) + textField.frame.height
offset = UIScreen.main.bounds.height - globalPointY
if keyboardHeight > 0 {
vc?.moveViewUp(offsetFromKeyboard: keyboardHeight - offset)
}
return true
}
}
extension UIViewController {
private func setTextFieldDelegates(parentView: UIView) {
for child in parentView.subviews {
setTextFieldDelegates(parentView: child)
(child as? UITextField)?.delegate = DelegateProxies.getDelegate(root: self)
}
}
func registerAutoResizeOnKeyboardAppear(){
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)
}
func unregisterAutoResizeOnKeyboard(){
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let offsetFromKeyboard = keyboardSize.height - DelegateProxies.getDelegate().offset
DelegateProxies.getDelegate().keyboardHeight = keyboardSize.height
moveViewUp(offsetFromKeyboard: offsetFromKeyboard)
}
}
func moveViewUp(offsetFromKeyboard: CGFloat){
print("offset from keyboard: \(offsetFromKeyboard)")
let moveOffset = offsetFromKeyboard + 8
if offsetFromKeyboard > 0 {
self.view.frame.origin.y = -moveOffset
}
if offsetFromKeyboard < 0 && view.frame.origin.y < 0 {
self.view.frame.origin.y += -moveOffset
if self.view.frame.origin.y > 0{
self.view.frame.origin.y = 0
}
}
}
@objc func keyboardWillHide(notification: NSNotification) {
self.view.frame.origin.y = 0
}
}
对于Swift 3，我做了一个UIViewController子类，因为我需要在所有的视图控制器中恒定的行为。
class SomeClassVC: UIViewController {
//MARK: - Lifecycle
override func viewDidLoad() {
super.viewDidLoad()
addKeyboardObservers()
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
removeKeyboardObservers()
}
//MARK: - Overrides
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
view.endEditing(true)
}
//MARK: - Help
func addKeyboardObservers() {
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)
}
func removeKeyboardObservers() {
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: self.view.window)
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: self.view.window)
}
func keyboardWillShow(notification: NSNotification) {
let keyboardHeight = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.height
UIView.animate(withDuration: 0.1, animations: { () -> Void in
self.view.window?.frame.origin.y = -1 * keyboardHeight!
self.view.layoutIfNeeded()
})
}
func keyboardWillHide(notification: NSNotification) {
UIView.animate(withDuration: 0.1, animations: { () -> Void in
self.view.window?.frame.origin.y = 0
self.view.layoutIfNeeded()
})
}
func resignTextFieldFirstResponders() {
for textField in self.view.subviews where textField is UITextField {
textField.resignFirstResponder()
}
}
func resignAllFirstResponders() {
view.endEditing(true)
}
}
这个视频教程是最好的。7分钟长，会很有意义。这样一个简单的解决方案，当你有多个文本字段，并希望滚动视图移动“x”数量的像素时，特定的文本字段被点击。
https://youtu.be/VuiPGJOEBH4
就这些步骤:
-把你所有的文本字段放在一个滚动视图中，约束到视图的边缘。
-连接所有的文本字段和滚动视图作为视图控制器的委托。
-用IBOutlet连接所有文本字段和滚动视图。
class ViewController: UIViewController, UITextFieldDelegate {
添加UITextFieldDelegate协议到你的类中
@IBOutlet var stateAddress: UITextField!
@IBOutlet var zipAddress: UITextField!
@IBOutlet var phoneNumber: UITextField!
@IBOutlet var vetEmailAddress: UITextField!
@IBOutlet weak var scrollView: UIScrollView!
-在swift文件中添加UITextFieldDelegate方法:
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
func textFieldDidBeginEditing(textField: UITextField) {
if (textField == self.stateAddress) {
scrollView.setContentOffset(CGPointMake(0, 25), animated: true)
}
else if (textField == self.zipAddress) {
scrollView.setContentOffset(CGPointMake(0, 57), animated: true)
}
else if (textField == self.phoneNumber) {
scrollView.setContentOffset(CGPointMake(0, 112), animated: true)
}
else if (textField == self.vetEmailAddress) {
scrollView.setContentOffset(CGPointMake(0, 142), animated: true)
}
}
func textFieldDidEndEditing(textField: UITextField) {
scrollView.setContentOffset(CGPointMake(0, 0), animated: true)
}
第一种方法只是激活键盘上的返回按钮来关闭键盘。第二个是当你点击到任何特定的文本域，然后设置你的滚动视图滚动的距离的y偏移(我的是基于我的视图控制器上的y位置25,57,112,142)。最后一个说，当你从键盘上点击时，滚动视图会回到原来的位置。
我使我的视图像素完美的这种方式!
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