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
这是我的解决方案(实际上这段代码是在你的视图中有几个文本字段的情况下，这也适用于当你有一个文本字段的情况下)
class MyViewController: UIViewController, UITextFieldDelegate {
@IBOutlet weak var firstTextField: UITextField!
@IBOutlet weak var secondTextField: UITextField!
var activeTextField: UITextField!
var viewWasMoved: Bool = false
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(PrintViewController.keyboardWillShow(_:)), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(PrintViewController.keyboardWillHide(_:)), name: UIKeyboardWillHideNotification, object: nil)
}
override func viewDidDisappear(animated: Bool) {
super.viewWillDisappear(animated)
NSNotificationCenter.defaultCenter().removeObserver(self)
}
func textFieldDidBeginEditing(textField: UITextField) {
self.activeTextField = textField
}
func textFieldDidEndEditing(textField: UITextField) {
self.activeTextField = nil
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
func keyboardWillShow(notification: NSNotification) {
let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
var aRect: CGRect = self.view.frame
aRect.size.height -= keyboardSize!.height
let activeTextFieldRect: CGRect? = activeTextField?.frame
let activeTextFieldOrigin: CGPoint? = activeTextFieldRect?.origin
if (!CGRectContainsPoint(aRect, activeTextFieldOrigin!)) {
self.viewWasMoved = true
self.view.frame.origin.y -= keyboardSize!.height
} else {
self.viewWasMoved = false
}
}
func keyboardWillHide(notification: NSNotification) {
if (self.viewWasMoved) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.frame.origin.y += keyboardSize.height
}
}
}
其他回答
我对初学者的两点建议: 在上面的例子中，有人改变坐标，其他人使用“自动调整蒙版”和其他约束:
正如苹果所说，不要将这三种逻辑混合在一起。 如果你在故事板中有约束，不要尝试改变x/y。这绝对行不通。
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
}
}
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
}
}
这是我的解决方案(实际上这段代码是在你的视图中有几个文本字段的情况下，这也适用于当你有一个文本字段的情况下)
class MyViewController: UIViewController, UITextFieldDelegate {
@IBOutlet weak var firstTextField: UITextField!
@IBOutlet weak var secondTextField: UITextField!
var activeTextField: UITextField!
var viewWasMoved: Bool = false
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(PrintViewController.keyboardWillShow(_:)), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(PrintViewController.keyboardWillHide(_:)), name: UIKeyboardWillHideNotification, object: nil)
}
override func viewDidDisappear(animated: Bool) {
super.viewWillDisappear(animated)
NSNotificationCenter.defaultCenter().removeObserver(self)
}
func textFieldDidBeginEditing(textField: UITextField) {
self.activeTextField = textField
}
func textFieldDidEndEditing(textField: UITextField) {
self.activeTextField = nil
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
func keyboardWillShow(notification: NSNotification) {
let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
var aRect: CGRect = self.view.frame
aRect.size.height -= keyboardSize!.height
let activeTextFieldRect: CGRect? = activeTextField?.frame
let activeTextFieldOrigin: CGPoint? = activeTextFieldRect?.origin
if (!CGRectContainsPoint(aRect, activeTextFieldOrigin!)) {
self.viewWasMoved = true
self.view.frame.origin.y -= keyboardSize!.height
} else {
self.viewWasMoved = false
}
}
func keyboardWillHide(notification: NSNotification) {
if (self.viewWasMoved) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.frame.origin.y += keyboardSize.height
}
}
}
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)
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