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FlintyLemming cfdfdfc662 new post
2024-09-26 17:07:23 +08:00

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+++ author = "FlintyLemming" title = "【归档】iOS 原生 UIKit 开发处理键盘遮挡输入框问题" slug = "1fd6cc7df7cf4583a7543b0018b32494" date = "2020-01-16" description = "" categories = ["Apple", "Coding"] tags = ["UIKit", "Swift"] image = "https://hf-public-source.mitsea.com:8840/images/blog/posts/2020/01/iOS%20%E5%8E%9F%E7%94%9F%20UIKit%20%E5%BC%80%E5%8F%91%E5%A4%84%E7%90%86%E9%94%AE%E7%9B%98%E9%81%AE%E6%8C%A1%E8%BE%93%E5%85%A5%E6%A1%86%E9%97%AE%E9%A2%98/slava-auchynnikau-B5nCJC-KpvA-unsplash.avif" +++

概要

目前项目中遇到小屏手机中弹出键盘时挡住输入框的问题,网上的方法我看都是要么修改当前 scrollview 的 offset要么是修改 .view.frame 的y轴位置。但该方法在页面纵幅较短的情况下会出现问题所以我这边使用修改约束的方法。

预想方法

通过修改最上方的元素到顶端的距离来实现需求

Risks

动画做起来的话,没有移动 frame 来的简单,不能用 animated: true得要自己写。当然我这边 base 里别人写好了。

Open Questions

也许移动 frame 可行,但我这边就是会出现之前视频上出现的那个问题,没有找到解决方法。

不过修改约束也没有经过长时间的充分测试,还没发现什么隐性问题。

核心步骤

  1. 在 xib 中找到约束,并拖入 view 文件中

  2. 起个名字

    @IBOutlet weak var topConstraint: NSLayoutConstraint!
    
  3. 在 ViewController 里计算应当修改的数值,并进行偏移

    @objc private func keyboardWillAppear(notification: NSNotification) {
        let keyboardRect = (notification.userInfo![UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
        let keyboardHeight = keyboardRect.size.height
        let screenHeight = self.view.frame.height
        let scrollViewOffset = cala001030View.scrollView.contentOffset.y
        let textFieldOffset = currentField.frame.origin.y - scrollViewOffset
        let visibleHeight = screenHeight - keyboardHeight - currentField.frame.size.height
    
        self.isNeedResetViewFrame = visibleHeight < textFieldOffset
        self.keyboardHeight = keyboardHeight
    
        let inputButtomToViewTop = currentField.frame.origin.y + currentField.frame.height + 30
        let keyboardTopToViewTop = screenHeight - keyboardHeight
        let shouldOffset = inputButtomToViewTop - keyboardTopToViewTop - scrollViewOffset
    
        if visibleHeight < textFieldOffset {
            self.cala001030View.topConstraint.constant = -shouldOffset
        }
    }
    

    关于偏移量是如何计算出来的,会单独开一个文章来说明

  4. 键盘收回时,恢复原来的约束即可

    @objc private func keyboardWillHide(notification: NSNotification) {
        self.cala001030View.topConstraint.constant = 0
    }
    

Photo by Slava Auchynnikau on Unsplash