Question

我正在尝试在UITextView中垂直中间对齐文本。搜索之后，我找到了代码，并且似乎可以正常工作，直到我们开始键入并在光标跳转时按回车。当我们在文本视图内键入内容时，按Enter键时，光标会跳转以调整其位置（由于其调用/实现的方式，我假设该位置）。

是否有更好，更优雅的解决方案？

我已将其实现为UITextView扩展名。该代码摘自Center text vertically in a UITextView

上建议的一种解决方案

我的问题是解决跳跃问题。这不是上述问题的重复。

extension UITextView {
    func alignTextVerticallyInContainer() {
        let fittingSize = CGSize(width: bounds.width, height: CGFloat.greatestFiniteMagnitude)
        let size = sizeThatFits(fittingSize)
        let topOffset = ((bounds.size.height - size.height * zoomScale) / 2)
        let positiveTopOffset = max(1, topOffset)
        contentOffset.y = -positiveTopOffset + 1
    }
}

然后从

调用

override func viewDidLayoutSubviews() {
    textView.alignTextVerticallyInContainer()
}

Answer 1

请选中此link以确保文本居中对齐。

 textView.textAlignment = .center

Answer 2

您只能使用自动布局来完成此操作-无需代码。

首先添加一个UIScrollView-我已将其限制为从顶部 80-pts ，每侧 20-pts 和一个高度限制为 240 （为了方便查看，我将背景设置为橙色）：

接下来，添加一个标准UIView作为scrollView的子视图（我将背景设置为青色以便于查看）。将其两侧，顶部和底部限制为 8点（需要一些填充）。约束其width等于scrollView Width，并具有 -16 常数（用于侧边填充），并约束其Height等于scrollView Height，也具有一个常数 -16 < / strong>（用于顶部/底部填充）。

关键点：将高度约束的优先级设置为低（250）。这将使它在需要时增长：

现在添加一个UITextView作为青色视图的子视图。仅以一行文本开始。从每一侧将其限制为 8点（用于填充）；在顶部和底部将其限制为> = 8-pts ；并在跨度视图中将其垂直居中进行约束：

运行该应用程序时，它应具有以下功能（再次，无需代码）：

以下是情节提要的来源：

<?xml version="1.0" encoding="UTF-8"?> <document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14460.31" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="LZe-dy-wRt"> <device id="retina4_7" orientation="portrait"> <adaptation id="fullscreen"/> </device> <dependencies> <deployment identifier="iOS"/> <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14460.20"/> <capability name="Safe area layout guides" minToolsVersion="9.0"/> <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/> </dependencies> <scenes>  <scene sceneID="k3M-Zu-xX0"> <objects> <viewController id="LZe-dy-wRt" sceneMemberID="viewController"> <view key="view" contentMode="scaleToFill" id="fZP-6s-NIY"> <rect key="frame" x="0.0" y="0.0" width="375" height="667"/> <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/> <subviews> <scrollView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="guO-HM-qxH"> <rect key="frame" x="20" y="100" width="335" height="240"/> <subviews> <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="zW5-KI-gna"> <rect key="frame" x="8" y="8" width="319" height="224"/> <subviews> <textView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" scrollEnabled="NO" text="Start with one line." textAlignment="natural" translatesAutoresizingMaskIntoConstraints="NO" id="S6g-U0-TeD"> <rect key="frame" x="8" y="95.5" width="303" height="33"/> <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/> <fontDescription key="fontDescription" type="system" pointSize="14"/> <textInputTraits key="textInputTraits" autocapitalizationType="sentences"/> </textView> </subviews> <color key="backgroundColor" red="0.45138680930000002" green="0.99309605359999997" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/> <constraints> <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="S6g-U0-TeD" secondAttribute="bottom" constant="8" id="Ewc-yq-KHO"/> <constraint firstItem="S6g-U0-TeD" firstAttribute="leading" secondItem="zW5-KI-gna" secondAttribute="leading" constant="8" id="RIE-gD-bX2"/> <constraint firstAttribute="trailing" secondItem="S6g-U0-TeD" secondAttribute="trailing" constant="8" id="SfV-e8-TXV"/> <constraint firstItem="S6g-U0-TeD" firstAttribute="top" relation="greaterThanOrEqual" secondItem="zW5-KI-gna" secondAttribute="top" constant="8" id="byT-nx-8K1"/> <constraint firstItem="S6g-U0-TeD" firstAttribute="centerY" secondItem="zW5-KI-gna" secondAttribute="centerY" id="qGs-hb-AdH"/> </constraints> </view> </subviews> <color key="backgroundColor" red="1" green="0.83234566450000003" blue="0.47320586440000001" alpha="1" colorSpace="custom" customColorSpace="sRGB"/> <constraints> <constraint firstAttribute="bottom" secondItem="zW5-KI-gna" secondAttribute="bottom" constant="8" id="1xU-wS-Qcb"/> <constraint firstItem="zW5-KI-gna" firstAttribute="top" secondItem="guO-HM-qxH" secondAttribute="top" constant="8" id="CgB-kT-vjH"/> <constraint firstItem="zW5-KI-gna" firstAttribute="leading" secondItem="guO-HM-qxH" secondAttribute="leading" constant="8" id="O4I-aF-PEV"/> <constraint firstAttribute="height" constant="240" id="OZD-dD-yht"/> <constraint firstAttribute="trailing" secondItem="zW5-KI-gna" secondAttribute="trailing" constant="8" id="QXI-Lh-37A"/> <constraint firstItem="zW5-KI-gna" firstAttribute="height" secondItem="guO-HM-qxH" secondAttribute="height" priority="250" constant="-16" id="dMe-rS-ZOO"/> <constraint firstItem="zW5-KI-gna" firstAttribute="width" secondItem="guO-HM-qxH" secondAttribute="width" constant="-16" id="pGF-wL-V4q"/> </constraints> </scrollView> </subviews> <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/> <constraints> <constraint firstItem="XpO-5d-W48" firstAttribute="trailing" secondItem="guO-HM-qxH" secondAttribute="trailing" constant="20" id="Mvu-Ug-NEY"/> <constraint firstItem="guO-HM-qxH" firstAttribute="leading" secondItem="XpO-5d-W48" secondAttribute="leading" constant="20" id="Rfe-Ev-3xj"/> <constraint firstItem="guO-HM-qxH" firstAttribute="top" secondItem="XpO-5d-W48" secondAttribute="top" constant="80" id="YhH-mc-af6"/> </constraints> <viewLayoutGuide key="safeArea" id="XpO-5d-W48"/> </view> </viewController> <placeholder placeholderIdentifier="IBFirstResponder" id="p5Q-GK-BKG" userLabel="First Responder" sceneMemberID="firstResponder"/> </objects> <point key="canvasLocation" x="-10" y="775"/> </scene> </scenes> </document>

如何在UITextView中的中间垂直对齐文本

2 个答案: