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
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。
其他回答
我注意到其他答案涉及从视图中删除一些顶部。如果你想简单地调整视图的大小而不削减任何内容，只需尝试这个方法:)
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.setTranslatesAutoresizingMaskIntoConstraints(true)
self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y, self.view.frame.size.width, self.view.frame.height - keyboardSize.height)
}
}
func keyboardWillHide(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.collectionView.setTranslatesAutoresizingMaskIntoConstraints(false)
self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y, self.view.frame.size.width, self.view.frame.height + keyboardSize.height)
}
}
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.frame.origin.y = self.view.frame.height - (self.view.frame.height + keyboardSize.height)
}
}
func keyboardWillHide(notification: NSNotification) {
self.view.frame.origin.y = 0
}
它必须更加稳定
这是一个解决方案，不处理从一个textField到另一个切换:
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) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.CGRectValue() {
self.view.frame.origin.y -= keyboardSize.height
}
}
func keyboardWillHide(notification: NSNotification) {
self.view.frame.origin.y = 0
}
要解决这个问题，将keyboardWillShow/Hide替换为以下两个函数:
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.CGRectValue() {
if view.frame.origin.y == 0 {
self.view.frame.origin.y -= keyboardSize.height
}
}
}
func keyboardWillHide(notification: NSNotification) {
if view.frame.origin.y != 0 {
self.view.frame.origin.y = 0
}
}
斯威夫特3.0:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0 {
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y = 0
}
}
斯威夫特4.0:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0 {
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y = 0
}
}
斯威夫特4.2:
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.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0 {
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y = 0
}
}
Swift 3代码
var activeField: UITextField?
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ProfileViewController.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ProfileViewController.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func textFieldDidBeginEditing(_ textField: UITextField){
activeField = textField
}
func textFieldDidEndEditing(_ textField: UITextField){
activeField = nil
}
func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if (self.activeField?.frame.origin.y)! >= keyboardSize.height {
self.view.frame.origin.y = keyboardSize.height - (self.activeField?.frame.origin.y)!
} else {
self.view.frame.origin.y = 0
}
}
}
func keyboardWillHide(notification: NSNotification) {
self.view.frame.origin.y = 0
}
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)
}
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