3.4 KiB
+++ 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
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在 xib 中找到约束,并拖入 view 文件中
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起个名字
@IBOutlet weak var topConstraint: NSLayoutConstraint!
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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
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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