仅在键盘覆盖输入字段时才向上移动视图

Question

我正在尝试为iPhone构建输入屏幕.屏幕有许多输入字段.其中大多数位于屏幕顶部,但两个字段位于底部.当用户尝试编辑屏幕底部的文本时,键盘将弹出并覆盖屏幕.我找到了一个简单的解决方案,可以在发生这种情况时将屏幕向上移动,但结果是屏幕总是向上移动,当用户尝试编辑屏幕时,屏幕顶部的字段会移动.

有没有办法让屏幕只在编辑底部字段时移动？

我使用了这里找到的代码:

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(sender: NSNotification) {
    self.view.frame.origin.y -= 150
}

func keyboardWillHide(sender: NSNotification) {
    self.view.frame.origin.y += 150
}

Answer 1

Apple在本文档中对您的问题进行了详细解释.此页面上的示例代码(at Listing 4-1)完全符合您的需要,只有在当前编辑应位于键盘下方时才会滚动视图.您只需要将所需的控件放在scrollViiew中.唯一的问题是这是Objective-C,我认为你需要它在Swift中...所以它是:它是:

声明一个变量

var activeField: UITextField?

然后添加这些方法

 func registerForKeyboardNotifications()
{
    //Adding notifies on keyboard appearing
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWasShown:", name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillBeHidden:", name: UIKeyboardWillHideNotification, object: nil)
}


func deregisterFromKeyboardNotifications()
{
    //Removing notifies on keyboard appearing
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}

func keyboardWasShown(notification: NSNotification)
{
    //Need to calculate keyboard exact size due to Apple suggestions
    self.scrollView.scrollEnabled = true
    var info : NSDictionary = notification.userInfo!
    var keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
    var contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize!.height, 0.0)

    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets

    var aRect : CGRect = self.view.frame
    aRect.size.height -= keyboardSize!.height
    if let activeFieldPresent = activeField
    {
        if (!CGRectContainsPoint(aRect, activeField!.frame.origin))
        {
            self.scrollView.scrollRectToVisible(activeField!.frame, animated: true)
        }
    }


}


func keyboardWillBeHidden(notification: NSNotification)
{
    //Once keyboard disappears, restore original positions
    var info : NSDictionary = notification.userInfo!
    var keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
    var contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, -keyboardSize!.height, 0.0)
    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets
    self.view.endEditing(true)
    self.scrollView.scrollEnabled = false

}

func textFieldDidBeginEditing(textField: UITextField!)
{
    activeField = textField
}

func textFieldDidEndEditing(textField: UITextField!)
{
    activeField = nil
}

请务必将ViewController声明为UITextFieldDelegate初始化方法并在初始化方法中设置正确的委托:ex:

self.you_text_field.delegate = self

并记得调用registerForKeyboardNotificationsviewInit并deregisterFromKeyboardNotifications退出.

编辑/更新:Swift 4.2语法

func registerForKeyboardNotifications(){
    //Adding notifies on keyboard appearing
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(notification:)), name: NSNotification.Name.UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(notification:)), name: NSNotification.Name.UIResponder.keyboardWillHideNotification, object: nil)
}

func deregisterFromKeyboardNotifications(){
    //Removing notifies on keyboard appearing
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIResponder.keyboardWillHideNotification, object: nil)
}

@objc func keyboardWasShown(notification: NSNotification){
    //Need to calculate keyboard exact size due to Apple suggestions
    self.scrollView.isScrollEnabled = true
    var info = notification.userInfo!
    let keyboardSize = (info[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
    let contentInsets : UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: keyboardSize!.height, right: 0.0)

    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets

    var aRect : CGRect = self.view.frame
    aRect.size.height -= keyboardSize!.height
    if let activeField = self.activeField {
        if (!aRect.contains(activeField.frame.origin)){
            self.scrollView.scrollRectToVisible(activeField.frame, animated: true)
        }
    }
}

@objc func keyboardWillBeHidden(notification: NSNotification){
    //Once keyboard disappears, restore original positions
    var info = notification.userInfo!
    let keyboardSize = (info[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
    let contentInsets : UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: -keyboardSize!.height, right: 0.0)
    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets
    self.view.endEditing(true)
    self.scrollView.isScrollEnabled = false
}

func textFieldDidBeginEditing(_ textField: UITextField){
    activeField = textField
}

func textFieldDidEndEditing(_ textField: UITextField){
    activeField = nil
}

Answer 2

这是我的2美分:

您是否尝试过:https://github.com/hackiftekhar/IQKeyboardManager

非常容易安装Swift或Objective-C.

它是如何工作的:

IQKeyboardManager(Swift): - IQKeyboardManagerSwift可通过CocoaPods获得,安装它只需将以下行添加到您的Podfile:(#236)

pod 'IQKeyboardManagerSwift'

在AppDelegate.swift中,只需导入IQKeyboardManagerSwift框架并启用IQKeyboardManager.

import IQKeyboardManagerSwift

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    IQKeyboardManager.sharedManager().enable = true
    // For Swift 4, use this instead
    // IQKeyboardManager.shared.enable = true


    return true
    }
}

这就是全部.简单!

Answer 3

我发现对我来说完美的工作是:

func textFieldDidBeginEditing(textField: UITextField) {
    if textField == email || textField == password {
        animateViewMoving(true, moveValue: 100)
    }
}

func textFieldDidEndEditing(textField: UITextField) {
    if textField == email || textField == password {
        animateViewMoving(false, moveValue: 100)
    }
}

func animateViewMoving (up:Bool, moveValue :CGFloat){
    let movementDuration:NSTimeInterval = 0.3
    let movement:CGFloat = ( up ? -moveValue : moveValue)

    UIView.beginAnimations("animateView", context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(movementDuration)

    self.view.frame = CGRectOffset(self.view.frame, 0, movement)
    UIView.commitAnimations()
}

您还可以更改高度值.如果要将其用于所有文本字段,请删除"if语句".

您甚至可以将此用于需要用户输入的所有控件,如TextView.

Answer 4

有没有办法让屏幕只在编辑底部字段时移动？

我有一个类似的问题,发现一个非常简单的解决方案,而不使用scrollView,而是在keyboardWillShow/Hide方法中使用if语句.

func keyboardWillShow(notification: NSNotification) {
    if bottomText.editing{
        self.view.window?.frame.origin.y = -1 * getKeyboardHeight(notification)
    }
}

func keyboardWillHide(notification: NSNotification) {
    if self.view.window?.frame.origin.y != 0 {
        self.view.window?.frame.origin.y += getKeyboardHeight(notification)
    }
}

这对我来说是一个很好的解决方案,因为我只有两个文本字段.

移动整个视图:仅在编辑某些文本字段(bottomText)时

向下移动整个视图:仅当视图不在原始位置时

Answer 5

出现键盘时，只需使用此扩展名即可移动任何UIView。

extension UIView {
    func bindToKeyboard(){
        NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillChange(_:)), name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)
    }

    @objc func keyboardWillChange(_ notification: NSNotification){
        let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
        let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
        let beginningFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
        let endFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

        let deltaY = endFrame.origin.y - beginningFrame.origin.y

        UIView.animateKeyframes(withDuration: duration, delay: 0.0, options: UIViewKeyframeAnimationOptions(rawValue: curve), animations: {
            self.frame.origin.y += deltaY
        }, completion: nil)
    }
}

然后在viewdidload中将视图绑定到键盘

UiView.bindToKeyboard()