仅当键盘覆盖输入字段时，才向上移动视图

Question

我正在尝试为iPhone构建一个输入屏幕。屏幕有一个进审量字段。它们大多在屏幕顶部，但底部有两个字段。当用户尝试编辑屏幕底部的文本时，键盘会弹出，它会覆盖屏幕。当这种情况发生时，我找到了一个简单的解决方案来向上移动屏幕，但结果是屏幕总是向上移动，当用户尝试编辑那些时，屏幕顶部的字段移动到够不着的地方。

是否有办法使屏幕仅在编辑底部字段时移动？

我使用了我在这里找到的代码：

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

我发现最适合我的是：

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“if语句”用于所有文本字段，请删除它。

您甚至可以将其用于所有需要用户输入的控件，如TextView。

Answer 2

这是我的2美分：

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

安装Swift或Objective-C非常容易。

其工作原理如下：

IQKeyboardManager（Swift）：-IQKeyboardManagerSwift通过CocoaPods提供，要安装它，只需在Podfile中添加以下行：（#236）

pod 'IQKeyboardManagerSwift'

在AppDelegate中。swift，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
    }
}

仅此而已。放松。

Answer 3

苹果公司在本文档中对您的问题进行了很好的解释。此页面上的示例代码（位于清单4-1）完全满足您的需要，只有当当前编辑应该在键盘下时，它才会滚动视图。您只需将所需的控件放在Scrollview中。唯一的问题是，这是Objective-C，我认为您需要在Swift中使用它。。所以这是：

声明变量

var activeField: UITextField?

然后加上这些方法

 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
}

请务必将您的ViewController声明为UITextFieldServer ate并在初始化方法中设置正确的委托：例如：

self.you_text_field.delegate = self

记住在viewInit上调用registerworkeyboardnotifications，在退出时调用从键盘通知中注销。

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
}