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当键盘隐藏时,为什么整个视图会突然出现?

nsnotification uikeyboard nsnotificationcenter swift ios

0

TheRedCamaro3.0 3.0 · 技术社区 · 7 年前

下面是我用来控制键盘通知的代码。我已经尝试过使用动画时间和布局限制,但我一直没能走得更远。关于如何修复的任何建议,谢谢。

基于建议编辑代码-我曾尝试按照建议为布局约束创建一个变量,但问题仍然存在,为什么?

import UIKit
import Foundation

extension UIView {
    func currentFirstResponder() -> UIResponder? {
        if self.isFirstResponder {
            return self
        }

        for view in self.subviews {
            if let responder = view.currentFirstResponder() {
                return responder
            }
        }

        return nil
    }
}

extension Notification.Name{
    static let showKeyboard = Notification.Name("showKeyboard")
}

class KeyboardSlider: NSObject {
    // variables to hold and process information from the view using this class
    weak var view: UIView?
    var searchBarTopTags:SearchBarTopTagsViewController?
    var amountToShiftBy:CGFloat!
    var originalFrame:CGRect!
    var previewController:PreviewController!

    @objc func keyboardWillShow(notification: NSNotification) {
self.searchBarTopTags?.myViewBottomLayoutConstraint.constant =  -self.getKeyboardHeight(notification as! Notification) + previewController.view.safeAreaInsets.bottom
        UIView.animate(withDuration: 0, animations: {
            self.view?.layoutIfNeeded()
            self.searchBarTopTags?.myView.layoutIfNeeded()

        })
    }

    @objc func keyboardWillHide(notification:NSNotification){

        self.searchBarTopTags?.myViewBottomLayoutConstraint.constant = 0
        UIView.animate(withDuration: 0, animations: {
            self.view?.layoutIfNeeded()
            self.searchBarTopTags?.myView.layoutIfNeeded()
        })
    }
    func getKeyboardHeight(_ notification:Notification) -> CGFloat {
        // get exact height of keyboard on all devices and convert to float value to return for use
        let userInfo = notification.userInfo
        let keyboardSize = userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue
        return keyboardSize.cgRectValue.height
    }

    func subscribeToKeyboardNotifications(view: UIView) {
        // assigning view to class' counterpart
        self.view = view
        // when UIKeyboardWillShow do keyboardWillShow function
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: .UIKeyboardWillShow, object: nil)
    }


    func subscribeToKeyboardNotifications(view: UIView, previewController:PreviewController? = nil) {
        // assigning view to class' counterpart
        self.view = view
        self.searchBarTopTags = previewController?.searchBarTopTags
        self.previewController = previewController

        // when UIKeyboardWillShow do keyboardWillShow function
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: .UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: .UIKeyboardWillHide, object: nil)
    }


    func unsubscribeFromKeyboardNotifications() {
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: nil)
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
    }

}

原始代码:

import UIKit
import Foundation

extension UIView {
    func currentFirstResponder() -> UIResponder? {
        if self.isFirstResponder {
            return self
        }

        for view in self.subviews {
            if let responder = view.currentFirstResponder() {
                return responder
            }
        }

        return nil
    }
}

extension Notification.Name{
    static let showKeyboard = Notification.Name("showKeyboard")
}

class KeyboardSlider: NSObject {
    // variables to hold and process information from the view using this class
    weak var view: UIView?
    var searchBarTopTags:SearchBarTopTagsViewController?
    var amountToShiftBy:CGFloat!
    var originalFrame:CGRect!

    @objc func keyboardWillShow(notification: NSNotification) {
        self.originalFrame = self.searchBarTopTags?.myView.frame
        self.amountToShiftBy = (self.searchBarTopTags?.view.frame.maxY)! - self.getKeyboardHeight(notification as! Notification) - (self.searchBarTopTags?.myView.frame.height)!
        self.amountToShiftBy = (searchBarTopTags?.view.bounds.height)! - self.getKeyboardHeight(notification as! Notification) - (searchBarTopTags?.myView.bounds.height)!
        self.searchBarTopTags?.myView.bottomAnchor.constraint(equalTo: (self.searchBarTopTags?.view.bottomAnchor)!, constant: -self.amountToShiftBy).isActive = true

        UIView.animate(withDuration: 0, animations: {
            self.view?.layoutIfNeeded()
            self.searchBarTopTags?.view.layoutIfNeeded()
            self.searchBarTopTags?.myView.layoutIfNeeded()        })

    }

    @objc func keyboardWillHide(notification:NSNotification){

        self.searchBarTopTags?.myView.bottomAnchor.constraint(equalTo: (self.searchBarTopTags?.view.bottomAnchor)!, constant: 0).isActive = true
        UIView.animate(withDuration: 0, animations: {
            self.view?.layoutIfNeeded()
            self.searchBarTopTags?.view.layoutIfNeeded()
            self.searchBarTopTags?.myView.layoutIfNeeded()
        })
    }
    func getKeyboardHeight(_ notification:Notification) -> CGFloat {
        // get exact height of keyboard on all devices and convert to float value to return for use
        let userInfo = notification.userInfo
        let keyboardSize = userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue
        return keyboardSize.cgRectValue.height
    }

    func subscribeToKeyboardNotifications(view: UIView) {
        // assigning view to class' counterpart
        self.view = view
        // when UIKeyboardWillShow do keyboardWillShow function
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: .UIKeyboardWillShow, object: nil)
    }


    func subscribeToKeyboardNotifications(view: UIView, seachBarTopTagsVC:SearchBarTopTagsViewController? = nil) {
        // assigning view to class' counterpart
        self.view = view
        self.searchBarTopTags = seachBarTopTagsVC

        // when UIKeyboardWillShow do keyboardWillShow function
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: .UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: .UIKeyboardWillHide, object: nil)
    }


    func unsubscribeFromKeyboardNotifications() {
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: nil)
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
    }

}

2 回复 | 直到 7 年前

1

Shehata Gamal 7 年前

在…内 keyboardWillShow 有

self.searchBarTopTags?.myView.bottomAnchor.constraint(equalTo: (self.searchBarTopTags?.view.bottomAnchor)!, constant: -self.amountToShiftBy).isActive = true

里面 keyboardWillHide

self.searchBarTopTags?.myView.bottomAnchor.constraint(equalTo: (self.searchBarTopTags?.view.bottomAnchor)!, constant: 0).isActive = true

当键盘隐藏/显示时,您只需创建一次底部约束,例如在中 viewDidLoad ,然后在这些方法中使用常量值,如下所示

var bottomConstraint:NSLayoutConstraint!

bottomConstraint = self.searchBarTopTags?.myView.bottomAnchor.constraint(equalTo: (self.searchBarTopTags?.view.bottomAnchor)!, constant: 0)
bottomConstraint.isActive = true

//

@objc func keyboardWillShow(notification: NSNotification) {

   // other code
   bottomConstraint.constant = -self.amountToShiftBy
}

@objc func keyboardWillHide(notification: NSNotification) {

   bottomConstraint.constant = 0 
   // other code
}

2

0

ukim 7 年前

每次调用以下行时,都会添加一个新约束:

self.searchBarTopTags?.myView.bottomAnchor.constraint(equalTo: (self.searchBarTopTags?.view.bottomAnchor)!, constant: -self.amountToShiftBy).isActive = true

您需要添加对约束的引用,只需更改其常量即可。

let constraint = self.searchBarTopTags?.myView.bottomAnchor.constraint...
contraint.constant = ...