Ios 根据UIScrollView中的内容调整UIView的大小

我在根UIView中有这样的布局层次结构，请参见图片： UIScrollView->UIView->UITextView

我在UITextView.textViewDidChange上的代码中动态更改UIScrollView视图的大小。 我对UIView.bottom有一个与Superview.bottom UIScrollView相等的约束。 在UITextView视图适合一个屏幕之前，一切都正常工作

如何以编程方式将UIView调整为等于UITextView大小

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您需要做的是：

将UITextView顶部/前导/尾随约束到其超级视图UIView 将UITextView底部约束到其superview底部UIView，使用>= 将UIView上/下/前导/尾随约束到其超级视图UIScrollView 将UIView的宽度和高度约束为其超级视图UIScrollView的宽度和高度 编辑高度约束并设置优先级：250 这将允许文本视图根据其内容垂直增长/收缩。UIView将保持在滚动视图的高度，直到文本视图变得太高而无法容纳为止。此时，低优先级将允许在文本视图增长时向下推UIView的底部边缘

以下是故事板中的布局：

<?xml version="1.0" encoding="UTF-8"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14490.70" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="VM1-mg-1mG">
    <device id="retina4_7" orientation="portrait">
        <adaptation id="fullscreen"/>
    </device>
    <dependencies>
        <deployment identifier="iOS"/>
        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14490.49"/>
        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
    </dependencies>
    <scenes>
        <!--View Controller-->
        <scene sceneID="jpE-FH-8e8">
            <objects>
                <viewController id="VM1-mg-1mG" sceneMemberID="viewController">
                    <view key="view" contentMode="scaleToFill" id="yS7-gh-XNz">
                        <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="gBx-Cd-lhB">
                                <rect key="frame" x="8" y="120" width="359" height="447"/>
                                <subviews>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="UGW-Gc-H5B">
                                        <rect key="frame" x="0.0" y="0.0" width="359" height="447"/>
                                        <subviews>
                                            <textView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" scrollEnabled="NO" text="This is the UITextView" textAlignment="natural" translatesAutoresizingMaskIntoConstraints="NO" id="wad-lw-VgC">
                                                <rect key="frame" x="20" y="20" width="319" height="45"/>
                                                <color key="backgroundColor" red="0.99942404029999998" green="0.98555368190000003" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                                <fontDescription key="fontDescription" type="system" pointSize="24"/>
                                                <textInputTraits key="textInputTraits" autocapitalizationType="sentences"/>
                                            </textView>
                                        </subviews>
                                        <color key="backgroundColor" red="0.52747867609999999" green="1" blue="0.55622484120000004" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                        <constraints>
                                            <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="wad-lw-VgC" secondAttribute="bottom" constant="20" id="43l-VA-TfK"/>
                                            <constraint firstItem="wad-lw-VgC" firstAttribute="top" secondItem="UGW-Gc-H5B" secondAttribute="top" constant="20" id="6gx-L4-rfK"/>
                                            <constraint firstAttribute="trailing" secondItem="wad-lw-VgC" secondAttribute="trailing" constant="20" id="Hze-tT-ctt"/>
                                            <constraint firstItem="wad-lw-VgC" firstAttribute="leading" secondItem="UGW-Gc-H5B" secondAttribute="leading" constant="20" id="O7m-RX-NHL"/>
                                        </constraints>
                                    </view>
                                </subviews>
                                <color key="backgroundColor" red="0.46202266219999999" green="0.83828371759999998" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                <constraints>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="top" secondItem="gBx-Cd-lhB" secondAttribute="top" id="9Ca-8i-QSo"/>
                                    <constraint firstAttribute="trailing" secondItem="UGW-Gc-H5B" secondAttribute="trailing" id="HpF-K7-pGb"/>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="width" secondItem="gBx-Cd-lhB" secondAttribute="width" id="T85-Nb-vFG"/>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="leading" secondItem="gBx-Cd-lhB" secondAttribute="leading" id="aKi-pE-7nq"/>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="height" secondItem="gBx-Cd-lhB" secondAttribute="height" priority="250" id="gMZ-MY-cZ4"/>
                                    <constraint firstAttribute="bottom" secondItem="UGW-Gc-H5B" secondAttribute="bottom" id="yBi-9n-Sd3"/>
                                </constraints>
                            </scrollView>
                        </subviews>
                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                        <constraints>
                            <constraint firstItem="gBx-Cd-lhB" firstAttribute="top" secondItem="1Le-6E-02N" secondAttribute="top" constant="100" id="IpO-b2-zbv"/>
                            <constraint firstItem="1Le-6E-02N" firstAttribute="trailing" secondItem="gBx-Cd-lhB" secondAttribute="trailing" constant="8" id="XVi-7E-3hn"/>
                            <constraint firstItem="gBx-Cd-lhB" firstAttribute="leading" secondItem="1Le-6E-02N" secondAttribute="leading" constant="8" id="at7-bP-fws"/>
                            <constraint firstItem="1Le-6E-02N" firstAttribute="bottom" secondItem="gBx-Cd-lhB" secondAttribute="bottom" constant="100" id="nhL-ST-z4d"/>
                        </constraints>
                        <viewLayoutGuide key="safeArea" id="1Le-6E-02N"/>
                    </view>
                </viewController>
                <placeholder placeholderIdentifier="IBFirstResponder" id="6C7-lr-bGI" userLabel="First Responder" sceneMemberID="firstResponder"/>
            </objects>
            <point key="canvasLocation" x="136.80000000000001" y="124.58770614692655"/>
        </scene>
    </scenes>
</document>

在运行时：

显示大量文本并向上滚动：

下面是故事板的来源—不需要代码—只有故事板：

<?xml version="1.0" encoding="UTF-8"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14490.70" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="VM1-mg-1mG">
    <device id="retina4_7" orientation="portrait">
        <adaptation id="fullscreen"/>
    </device>
    <dependencies>
        <deployment identifier="iOS"/>
        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14490.49"/>
        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
    </dependencies>
    <scenes>
        <!--View Controller-->
        <scene sceneID="jpE-FH-8e8">
            <objects>
                <viewController id="VM1-mg-1mG" sceneMemberID="viewController">
                    <view key="view" contentMode="scaleToFill" id="yS7-gh-XNz">
                        <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="gBx-Cd-lhB">
                                <rect key="frame" x="8" y="120" width="359" height="447"/>
                                <subviews>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="UGW-Gc-H5B">
                                        <rect key="frame" x="0.0" y="0.0" width="359" height="447"/>
                                        <subviews>
                                            <textView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" scrollEnabled="NO" text="This is the UITextView" textAlignment="natural" translatesAutoresizingMaskIntoConstraints="NO" id="wad-lw-VgC">
                                                <rect key="frame" x="20" y="20" width="319" height="45"/>
                                                <color key="backgroundColor" red="0.99942404029999998" green="0.98555368190000003" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                                <fontDescription key="fontDescription" type="system" pointSize="24"/>
                                                <textInputTraits key="textInputTraits" autocapitalizationType="sentences"/>
                                            </textView>
                                        </subviews>
                                        <color key="backgroundColor" red="0.52747867609999999" green="1" blue="0.55622484120000004" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                        <constraints>
                                            <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="wad-lw-VgC" secondAttribute="bottom" constant="20" id="43l-VA-TfK"/>
                                            <constraint firstItem="wad-lw-VgC" firstAttribute="top" secondItem="UGW-Gc-H5B" secondAttribute="top" constant="20" id="6gx-L4-rfK"/>
                                            <constraint firstAttribute="trailing" secondItem="wad-lw-VgC" secondAttribute="trailing" constant="20" id="Hze-tT-ctt"/>
                                            <constraint firstItem="wad-lw-VgC" firstAttribute="leading" secondItem="UGW-Gc-H5B" secondAttribute="leading" constant="20" id="O7m-RX-NHL"/>
                                        </constraints>
                                    </view>
                                </subviews>
                                <color key="backgroundColor" red="0.46202266219999999" green="0.83828371759999998" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                <constraints>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="top" secondItem="gBx-Cd-lhB" secondAttribute="top" id="9Ca-8i-QSo"/>
                                    <constraint firstAttribute="trailing" secondItem="UGW-Gc-H5B" secondAttribute="trailing" id="HpF-K7-pGb"/>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="width" secondItem="gBx-Cd-lhB" secondAttribute="width" id="T85-Nb-vFG"/>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="leading" secondItem="gBx-Cd-lhB" secondAttribute="leading" id="aKi-pE-7nq"/>
                                    <constraint firstItem="UGW-Gc-H5B" firstAttribute="height" secondItem="gBx-Cd-lhB" secondAttribute="height" priority="250" id="gMZ-MY-cZ4"/>
                                    <constraint firstAttribute="bottom" secondItem="UGW-Gc-H5B" secondAttribute="bottom" id="yBi-9n-Sd3"/>
                                </constraints>
                            </scrollView>
                        </subviews>
                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                        <constraints>
                            <constraint firstItem="gBx-Cd-lhB" firstAttribute="top" secondItem="1Le-6E-02N" secondAttribute="top" constant="100" id="IpO-b2-zbv"/>
                            <constraint firstItem="1Le-6E-02N" firstAttribute="trailing" secondItem="gBx-Cd-lhB" secondAttribute="trailing" constant="8" id="XVi-7E-3hn"/>
                            <constraint firstItem="gBx-Cd-lhB" firstAttribute="leading" secondItem="1Le-6E-02N" secondAttribute="leading" constant="8" id="at7-bP-fws"/>
                            <constraint firstItem="1Le-6E-02N" firstAttribute="bottom" secondItem="gBx-Cd-lhB" secondAttribute="bottom" constant="100" id="nhL-ST-z4d"/>
                        </constraints>
                        <viewLayoutGuide key="safeArea" id="1Le-6E-02N"/>
                    </view>
                </viewController>
                <placeholder placeholderIdentifier="IBFirstResponder" id="6C7-lr-bGI" userLabel="First Responder" sceneMemberID="firstResponder"/>
            </objects>
            <point key="canvasLocation" x="136.80000000000001" y="124.58770614692655"/>
        </scene>
    </scenes>
</document>

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您可以为此创建一个约束吗，例如UIView大小为X，在textViewDidChange上使用constraint.constant=newSizeIt除了在某些情况下可以工作外，但我得到一个错误：无法同时满足约束。如果UIScrollView中有UITextView，是否可以删除scrollView和ViewView垂直中心的约束？禁用文本视图上的滚动。然后，它将根据文本自动调整其高度。像使用任何其他视图一样使用约束，例如，行数设置为零的UILabel。@m1sh0，我在UIBuilder中遇到错误-需要约束：Y位置或高度