使用 Swift 使用键盘移动视图

Question

我有一个应用程序，在视图的下半部分有一个文本字段。这意味着当我输入文本字段时，键盘会覆盖文本字段。

我将如何在打字时向上移动视图，以便我可以看到我正在输入的内容，然后在键盘消失时将其移回原来的位置？

我到处寻找，但所有解决方案似乎都在 Obj-C 中，我还不能完全转换。

任何帮助将不胜感激。

Answer 1

这是一个解决方案，无需处理从一个文本字段到另一个文本字段的切换：

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
}

要解决此问题，请将这两个函数替换为keyboardWillShow/Hide：

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
    }
}