Swift：仅在键盘隐藏TextField或Button时滚动查看 [英] Swift: Scroll View only when a TextField or Button is hidden by the Keyboard

问题描述

下面是我试图使用的代码，只有在键盘隐藏了聚焦的textField或UIButton时才能滚动视图：

  import UIKit 
 
 class ViewController：UIViewController，UITextFieldDelegate {
 
 @IBOutlet weak var buttonToBottomConstraint：NSLayoutConstraint！ 
 
 @IBOutlet weak var textFieldUsername：UITextField！ 
 @IBOutlet weak var textFieldPassword：UITextField！ 
 @IBOutlet弱var scrollView：UIScrollView！ 
 
 
覆盖func viewDidLoad（）{
 super.viewDidLoad（）
 
 NSNotificationCenter.defaultCenter（）。addObserver（self，selector：keyboardWillBeHidden： ，name：UIKeyboardWillHideNotification，object：nil）
 
 NSNotificationCenter.defaultCenter（）。addObserver（self，selector：keyboardWillBeShown：，name：UIKeyboardWillShowNotification，object：nil）
} 
 
 func textFieldDidBeginEditing（textField：UITextField）{
} 
 
 func textFieldShouldReturn（textField：UITextField） - > Bool {textField.resignFirstResponder（）
 
返回true 
} 
 
 func keyboardWillBeHidden（通知：NSNotification）{
 
 self.scrollView。 setContentOffset（CGPointMake（0,0），animated：true）
} 
 
 func keyboardWillBeShown（通知：NSNotification）{
 
 let userInfo = notification.userInfo！ 
 
如果让kbsize = userInfo [UIKeyboardFrameBeginUserInfoKey] ?. CGRectValue（）。size {
 
 self.scrollView .setContentOffset（CGPointMake（0，kbsize.or），animated：true ）
} 
} 
} 
  

问题：视图滚动即使键盘没有隐藏任何东西。

启动时查看：

点击TextField时查看：

问题：如何检查键盘是否隐藏了聚焦区域，如果是，请将其推到上方？

项目：

解决方案

  var currentTextField：UITextField？ 
 
 @IBOutlet weak var textFieldUsername：UITextField！ 
 @IBOutlet weak var textFieldPassword：UITextField！ 
 @IBOutlet弱var scrollView：UIScrollView！ 
 
 
覆盖func viewDidLoad（）
 {
 super.viewDidLoad（）
 
 NSNotificationCenter.defaultCenter（）。addObserver（self，selector ：keyboardWillBeHidden：，name：UIKeyboardWillHideNotification，object：nil）
 
 NSNotificationCenter.defaultCenter（）。addObserver（self，selector：keyboardWillBeShown：，name：UIKeyboardWillShowNotification，object：nil）
} 
 
 func textFieldDidBeginEditing（textField：UITextField）
 {
 currentTextField = textField; 
} 
 
 func textFieldShouldReturn（textField：UITextField） - > Bool {
 textField.resignFirstResponder（）
 
返回true 
} 
 
 func keyboardWillBeHidden（通知：NSNotification）{
 currentTextField = nil; 
 self.scrollView.setContentOffset（CGPointMake（0,0），animated：true）
} 
 
 func keyboardWillBeShown（通知：NSNotification）{
 
让userInfo = notification.userInfo！ 
 
如果让kbsize = userInfo [UIKeyboardFrameBeginUserInfoKey] ?. CGRectValue（）。size 
 {
 let contentInsets = UIEdgeInsets（top：0，left：0，bottom：kbsize.height ，右：0）
让screenSize：CGRect = UIScreen.mainScreen（）。bounds 
让screenHeight = screenSize.height 
 let height：CGFloat = screenHeight-（kbsize.height） - （currentTextField ！.frame.size.width）
 
 if（currentTextField！.frame.origin.y> = height）
 {
 var scrollPoint：CGPoint = CGPointMake（0.0，currentTextField！ .frame.origin.y  - （kbsize.height））; 
 self.scrollView .setContentOffset（scrollPoint，animated：true）
} 
 
} 
} 
 
 func textFieldDidEndEditing（textField：UITextField） {
 currentTextField = nil; 
} 
  

Below is the code that I'm trying to use to have the view scroll only when the focused textField or UIButton is hidden by the keyboard:

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet weak var buttonToBottomConstraint: NSLayoutConstraint!

    @IBOutlet weak var textFieldUsername: UITextField!
    @IBOutlet weak var textFieldPassword: UITextField!
    @IBOutlet weak var scrollView: UIScrollView!


    override func viewDidLoad() {
        super.viewDidLoad()

        NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillBeHidden:", name: UIKeyboardWillHideNotification, object: nil)

        NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillBeShown:", name: UIKeyboardWillShowNotification, object: nil)
    }

    func textFieldDidBeginEditing(textField: UITextField) {
    }

    func textFieldShouldReturn(textField: UITextField) -> Bool {textField.resignFirstResponder()

        return true
    }

    func keyboardWillBeHidden(notification: NSNotification){

        self.scrollView.setContentOffset(CGPointMake(0, 0), animated: true)
    }

    func keyboardWillBeShown(notification: NSNotification){

        let userInfo = notification.userInfo!

        if let kbsize = userInfo[UIKeyboardFrameBeginUserInfoKey]?.CGRectValue().size{

             self.scrollView .setContentOffset(CGPointMake(0, kbsize.or), animated: true)
        }
    }
}

Problem: The View scrolls even when the keyboard is not hiding anything.

View at Launch:

View Upon Tapping on a TextField:

Question: How do I check to see if the focused field is hidden by the keyboard, and ONLY if it is, push it above it?

Project: TextFieldScroll

EDIT

App works fine in Portrait mode, however, not in landscape mode. Also in landscape mode, when the Username textField keyboard is up and I tap the Password textField, it remains hidden behind the keyboard. I updated the project on Github and fixed the link. Thanks

Screen shot in landscape:

解决方案

var currentTextField:UITextField?

@IBOutlet weak var textFieldUsername: UITextField!
@IBOutlet weak var textFieldPassword: UITextField!
@IBOutlet weak var scrollView: UIScrollView!


override func viewDidLoad() 
{
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillBeHidden:", name: UIKeyboardWillHideNotification, object: nil)

    NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillBeShown:", name: UIKeyboardWillShowNotification, object: nil)
}

func textFieldDidBeginEditing(textField: UITextField)
{
currentTextField=textField;
}

func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()

    return true
}

func keyboardWillBeHidden(notification: NSNotification){
      currentTextField=nil;
    self.scrollView.setContentOffset(CGPointMake(0, 0), animated: true)
}

func keyboardWillBeShown(notification: NSNotification){

    let userInfo = notification.userInfo!

    if let kbsize = userInfo[UIKeyboardFrameBeginUserInfoKey]?.CGRectValue().size
    {
          let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: kbsize.height, right: 0)
        let screenSize: CGRect = UIScreen.mainScreen().bounds
       let screenHeight = screenSize.height
        let height:CGFloat=screenHeight-(kbsize.height)-(currentTextField!.frame.size.width)

         if(currentTextField!.frame.origin.y>=height )
        {
            var scrollPoint: CGPoint  = CGPointMake(0.0, currentTextField!.frame.origin.y - (kbsize.height));
            self.scrollView .setContentOffset(scrollPoint, animated: true)
        }

    }
}

  func textFieldDidEndEditing(textField: UITextField) {
     currentTextField=nil;
   }

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