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
override func viewWillAppear(animated: Bool)
{
super.viewWillAppear(animated)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)
}
// MARK: - keyboard
func keyboardWillShow(notification: NSNotification)
{
if let userInfo = notification.userInfo {
if let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
let contentInsets = self.tblView.contentInset as UIEdgeInsets
self.tblView.contentInset = UIEdgeInsets(top: contentInsets.top, left: contentInsets.left, bottom: keyboardSize.height, right:contentInsets.right)
// ...
} else {
// no UIKeyboardFrameBeginUserInfoKey entry in userInfo
}
} else {
// no userInfo dictionary in notification
}
}
func keyboardWillHide(notification: NSNotification)
{
let contentInsets = self.tblView.contentInset as UIEdgeInsets
self.tblView.contentInset = UIEdgeInsets(top: contentInsets.top, left: contentInsets.left, bottom: 0, right:contentInsets.right)
}
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)
}
当打开键盘时，它100%完美地回答了所有人的更新表视图高度
对于Swift4.2
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(RecipeVC.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(RecipeVC.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
if ((notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue) != nil {
var userInfo = notification.userInfo!
var keyboardFrame:CGRect = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
keyboardFrame = self.view.convert(keyboardFrame, from: nil)
var contentInset:UIEdgeInsets = self.tbl.contentInset
contentInset.bottom = keyboardFrame.size.height
self.tbl.contentInset = contentInset
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if ((notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue) != nil {
let contentInset:UIEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
self.tbl.contentInset = contentInset
}
}
Swift3.2
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(RecipeVC.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(RecipeVC.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func keyboardWillShow(notification: NSNotification) {
if ((notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue) != nil {
//self.view.frame.origin.y -= keyboardSize.height
var userInfo = notification.userInfo!
var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
keyboardFrame = self.view.convert(keyboardFrame, from: nil)
var contentInset:UIEdgeInsets = self.tbl.contentInset
contentInset.bottom = keyboardFrame.size.height
self.tbl.contentInset = contentInset
}
}
func keyboardWillHide(notification: NSNotification) {
if ((notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue) != nil {
let contentInset:UIEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
self.tbl.contentInset = contentInset
}
}
我看到所有的答案都是通过键盘高度的值移动视图本身。好吧，我有一个详细的答案，这可能是有用的，如果你正在使用约束即自动布局，移动一个视图通过改变其约束值(底部或顶部约束为例)由一个预定义的值或你可以使用键盘大小值。
在这个例子中，我使用底部约束从文本字段到底部布局视图的初始值为175。
@IBOutlet weak var bottomConstraint: NSLayoutConstraint!
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);
}
func keyboardWillShow(notification: NSNotification) {
//To retrieve keyboard size, uncomment following line
//let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
bottomConstraint.constant = 260
UIView.animateWithDuration(0.3) {
self.view.layoutIfNeeded()
}
}
func keyboardWillHide(notification: NSNotification) {
//To retrieve keyboard size, uncomment following line
//let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
bottomConstraint.constant = 175
UIView.animateWithDuration(0.3) {
self.view.layoutIfNeeded()
}
}
由于在Combine中没有如何做到这一点的答案，这里是我使用的方法。
我们创建一个发布者来监听通知，显示和隐藏。 为了显示，我们从通知userInfo中获取键盘帧，并检查当前活动响应器是否包含在其中。如果被覆盖，返回键盘帧高度。如果它没有被覆盖，返回0，我们不想移动帧。对于隐藏通知，我们简单地返回0。
private var keyboardHeightPublisher: AnyPublisher<CGFloat, Never> {
Publishers.Merge(
NotificationCenter.default
.publisher(for: UIResponder.keyboardWillShowNotification)
.compactMap { $0.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect }
.map { $0.intersects(self.view.firstResponder!.frame) ? $0.height : 0 }
.map { $0 * -1 },
NotificationCenter.default
.publisher(for: UIResponder.keyboardWillHideNotification)
.map { _ in CGFloat(0) }
).eraseToAnyPublisher()
}
在viewDidLoad中，我们只需订阅发布者，相应地改变视图框架。
override func viewDidLoad() {
super.viewDidLoad()
keyboardHeightPublisher.sink{ [weak self] height in
self?.view.frame.origin.y = height
}.store(in: &cancelables)
}
编辑 小心!如果firstResponder在子视图中，你必须计算与整个屏幕相对应的帧，以检查它们是否相交。 例子:
let myViewGlobalFrame = myView.convert(myView.frame, to: parentView)
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)
}
}
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