如何在键盘存在时使UITextField向上移动？

Question

如何防止UITextField键盘隐藏？

Answer 1

我假设这是在UIViewController上发生的.如果是这样,您可以设置在键盘显示/隐藏时调用以下2个函数,并在其块中进行适当响应.

设置UIViewController:

class XXXViewController: UIViewController, UITextFieldDelegate... {

    var frameView: UIView!

首先,在ViewDidLoad中:

override func viewDidLoad() {

    self.frameView = UIView(frame: CGRectMake(0, 0, self.view.bounds.width, self.view.bounds.height))


    // Keyboard stuff.
    let center: NSNotificationCenter = NSNotificationCenter.defaultCenter()
        center.addObserver(self, selector: #selector(ATReportContentViewController.keyboardWillShow(_:)), name: UIKeyboardWillShowNotification, object: nil)
    center.addObserver(self, selector: #selector(ATReportContentViewController.keyboardWillHide(_:)), name: UIKeyboardWillHideNotification, object: nil)
}

然后实现以下2个函数以响应上面ViewDidLoad中定义的NSNotificationCenter函数.我给你一个移动整个视图的例子,但你也可以只为UITextFields制作动画.

func keyboardWillShow(notification: NSNotification) {
    let info:NSDictionary = notification.userInfo!
    let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue()

    let keyboardHeight: CGFloat = keyboardSize.height

    let _: CGFloat = info[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber as CGFloat


    UIView.animateWithDuration(0.25, delay: 0.25, options: UIViewAnimationOptions.CurveEaseInOut, animations: {
        self.frameView.frame = CGRectMake(0, (self.frameView.frame.origin.y - keyboardHeight), self.view.bounds.width, self.view.bounds.height)
        }, completion: nil)

}

func keyboardWillHide(notification: NSNotification) {
    let info: NSDictionary = notification.userInfo!
    let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue()

    let keyboardHeight: CGFloat = keyboardSize.height

    let _: CGFloat = info[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber as CGFloat

    UIView.animateWithDuration(0.25, delay: 0.25, options: UIViewAnimationOptions.CurveEaseInOut, animations: {
        self.frameView.frame = CGRectMake(0, (self.frameView.frame.origin.y + keyboardHeight), self.view.bounds.width, self.view.bounds.height)
        }, completion: nil)

}

离开视图时不要忘记删除通知

override func viewWillDisappear(animated: Bool) {
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}

Answer 2

这是Swift中的简单解决方案.我翻译了一些过去对我有用的Objective-C代码.

func textFieldDidBeginEditing(textField: UITextField) { // became first responder

    //move textfields up
    let myScreenRect: CGRect = UIScreen.mainScreen().bounds
    let keyboardHeight : CGFloat = 216

    UIView.beginAnimations( "animateView", context: nil)
    var movementDuration:NSTimeInterval = 0.35
    var needToMove: CGFloat = 0

    var frame : CGRect = self.view.frame
    if (textField.frame.origin.y + textField.frame.size.height + /*self.navigationController.navigationBar.frame.size.height + */UIApplication.sharedApplication().statusBarFrame.size.height > (myScreenRect.size.height - keyboardHeight)) {
    needToMove = (textField.frame.origin.y + textField.frame.size.height + /*self.navigationController.navigationBar.frame.size.height +*/ UIApplication.sharedApplication().statusBarFrame.size.height) - (myScreenRect.size.height - keyboardHeight);
    }

    frame.origin.y = -needToMove
    self.view.frame = frame
    UIView.commitAnimations()
}

func textFieldDidEndEditing(textField: UITextField) {
        //move textfields back down
        UIView.beginAnimations( "animateView", context: nil)
        var movementDuration:NSTimeInterval = 0.35
        var frame : CGRect = self.view.frame
        frame.origin.y = 0
        self.view.frame = frame
        UIView.commitAnimations()
}

Answer 3

Swift 4代码,它非常简单,而不是使用像NSNotificationCenter这样的很多东西,然后计算所有东西的高度并创造条件使这更复杂,

下面编写了简单的方法,它可以向上移动视图.

func textFieldDidBeginEditing(_ textField: UITextField) {
        moveTextField(textfield: textField, moveDistance: -250, up: true)
}

func textFieldDidEndEditing(_ textField: UITextField) {
        moveTextField(textfield: textField, moveDistance: -250, up: false)
}

func moveTextField(textfield: UITextField, moveDistance: Int, up: Bool) {
    let moveDuration = 0.3
    let movement: CGFloat = CGFloat(up ? moveDistance: -moveDistance)
    UIView.beginAnimations("animateTextField", context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(moveDuration)
    self.view.frame = self.view.frame.offsetBy(dx: 0, dy: movement)
    UIView.commitAnimations()
}

您可以根据文本字段的位置更改-250值.