ios - UITableViewCell 按钮在屏幕下方加载时未注册单击

Question

我的主视图是 ScrollView ，在该 View 内我有一个内容 View 。在这个 View 中我有三个不同的表格 View 。 TableView 的行数是可变的，我在运行时根据单元格的数量设置每个 TableView 的高度。

例如TableView 1 的行高为 72，在运行时有三行。所以tableView高度等于72*3 = 216

然后，我禁用 TableView 的滚动，以便可以轻松地滚动整个 View 。在每个 tableView 单元格中都有执行某些操作的按钮。这些按钮使用按钮标签和与每个按钮相关的操作可以完美地工作。但这就是问题所在......

这些按钮仅在初始加载时位于屏幕上时才起作用。如果我的 ScrollView 超过屏幕底部，所有按钮都会变为非事件状态。无论什么 TableView 超出屏幕边缘，下面的所有按钮都将不再起作用。

我读过一些关于在加载 tableView 数据之前将内容 View 高度设置为 ScrollView 的整个高度的论坛，但这似乎不起作用。这是我在加载 tableData 之前用来更改 ScrollView /内容 View 高度的代码。我可以显示您认为有必要帮助解决该问题的任何其他代码。

totalHeight = self.friendsTableHeight.constant + self.invitationsTableHeight.constant + self.suggestionsTableHeight.constant + 350
self.scrollView.contentSize = CGSize(width: UIScreen.main.bounds.width, height: totalHeight)
self.contentViewHeight.constant = totalHeight

DispatchQueue.main.async {
    self.suggestionsTable.dataSource = self
    self.friendsTableView.dataSource = self
    self.invitationsTableView.dataSource = self
    self.suggestionsTable.reloadData()
    self.friendsTableView.reloadData()
    self.invitationsTableView.reloadData()
}

我还尝试将 contentView 设置为 ClipToBounds，但这会切断屏幕下方表格的任何部分。现在已经研究了几个小时，希望有人以前遇到过这个!

Answer 1

如果没有看到更多代码或如何设置约束，很难说你做错了什么。然而...

这里是一个简单的例子，在一个scrollView中垂直布局了3个tableView，它们之间有40点的垂直间距。无论滚动位置如何，单元格中的按钮都可以正常工作。

Storyboard布局如下所示:

结果:

向下滚动后:

代码:

//
//  TablesInScrollViewController.swift
//
//  Created by Don Mag on 11/7/18.
//

import UIKit

class ButtonCell: UITableViewCell {

    let theButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.setContentHuggingPriority(.required, for: .horizontal)
        v.backgroundColor = .yellow
        v.setTitleColor(.blue, for: .normal)
        v.setTitle("Button", for: .normal)
        return v
    }()

    let theLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .cyan
        return v
    }()

    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        commonInit()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }

    func commonInit() -> Void {

        contentView.addSubview(theLabel)
        contentView.addSubview(theButton)

        NSLayoutConstraint.activate([

            theLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 8.0),
            theLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 8.0),
            theLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -8.0),

            theButton.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -8.0),
            theButton.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 8.0),
            theButton.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -8.0),

            theLabel.trailingAnchor.constraint(equalTo: theButton.leadingAnchor, constant: -8.0),

            ])

        theButton.addTarget(self, action: #selector(buttonTapped(_:)), for: .touchUpInside)
    }

    @objc func buttonTapped(_ sender: Any) {
        print("Button tapped for:", theLabel.text ?? "")
    }

}

class TablesInScrollViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBOutlet var tableA: UITableView!
    @IBOutlet var tableB: UITableView!
    @IBOutlet var tableC: UITableView!

    @IBOutlet var tableAHeightConstraint: NSLayoutConstraint!
    @IBOutlet var tableBHeightConstraint: NSLayoutConstraint!
    @IBOutlet var tableCHeightConstraint: NSLayoutConstraint!

    var aData = ["A - 1", "A - 2", "A - 3", "A - 4", "A - 5", "A - 6"]
    var bData = ["B - 1", "B - 2", "B - 3", "B - 4", "B - 5", "B - 6", "B - 7", "B - 8", "B - 9", "B - 10"]
    var cData = ["C - 1", "C - 2", "C - 3", "C - 4"]

    var rHeight = 72

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let theData = tableView.isEqual(tableA) ? aData : tableView.isEqual(tableB) ? bData : cData
        return theData.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "ButtonCell", for: indexPath) as! ButtonCell

        let theData = tableView.isEqual(tableA) ? aData : tableView.isEqual(tableB) ? bData : cData
        cell.theLabel.text = theData[indexPath.row]

        return cell

    }

    override func viewDidLoad() {
        super.viewDidLoad()

        [tableA, tableB, tableC].forEach {
            $0?.dataSource = self
            $0?.delegate = self
            $0?.register(ButtonCell.self, forCellReuseIdentifier: "ButtonCell")
            $0?.rowHeight = CGFloat(rHeight)
        }

        tableAHeightConstraint.constant = CGFloat(rHeight * aData.count)
        tableBHeightConstraint.constant = CGFloat(rHeight * bData.count)
        tableCHeightConstraint.constant = CGFloat(rHeight * cData.count)

    }

}

和 Storyboard源(帮助您获得正确的约束):

<?xml version="1.0" encoding="UTF-8"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14109" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="llR-vr-4Zy">
    <device id="retina4_7" orientation="portrait">
        <adaptation id="fullscreen"/>
    </device>
    <dependencies>
        <deployment identifier="iOS"/>
        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14088"/>
        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
    </dependencies>
    <scenes>
        <!--Tables In Scroll View Controller-->
        <scene sceneID="7Zm-EI-Mg7">
            <objects>
                <viewController id="llR-vr-4Zy" customClass="TablesInScrollViewController" customModule="SW4Temp" customModuleProvider="target" sceneMemberID="viewController">
                    <view key="view" contentMode="scaleToFill" id="tw7-gs-oZR">
                        <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="GnA-uY-k8D">
                                <rect key="frame" x="20" y="40" width="335" height="607"/>
                                <subviews>
                                    <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="-1" estimatedRowHeight="-1" sectionHeaderHeight="28" sectionFooterHeight="28" translatesAutoresizingMaskIntoConstraints="NO" id="PBs-dW-Koi">
                                        <rect key="frame" x="7.5" y="8" width="319" height="128"/>
                                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                        <constraints>
                                            <constraint firstAttribute="height" constant="128" id="BKq-4w-98u"/>
                                        </constraints>
                                    </tableView>
                                    <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="-1" estimatedRowHeight="-1" sectionHeaderHeight="28" sectionFooterHeight="28" translatesAutoresizingMaskIntoConstraints="NO" id="nk6-mF-h3T">
                                        <rect key="frame" x="7.5" y="176" width="319" height="128"/>
                                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                        <constraints>
                                            <constraint firstAttribute="height" constant="128" id="Z9y-eh-Yju"/>
                                        </constraints>
                                    </tableView>
                                    <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="-1" estimatedRowHeight="-1" sectionHeaderHeight="28" sectionFooterHeight="28" translatesAutoresizingMaskIntoConstraints="NO" id="Exi-mx-rcW">
                                        <rect key="frame" x="7.5" y="344" width="319" height="128"/>
                                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                        <constraints>
                                            <constraint firstAttribute="height" constant="128" id="qti-gs-wLU"/>
                                        </constraints>
                                    </tableView>
                                </subviews>
                                <color key="backgroundColor" red="0.0" green="0.58980089430000004" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                <constraints>
                                    <constraint firstItem="PBs-dW-Koi" firstAttribute="width" secondItem="GnA-uY-k8D" secondAttribute="width" constant="-16" id="Axl-cT-hm3"/>
                                    <constraint firstItem="Exi-mx-rcW" firstAttribute="top" secondItem="nk6-mF-h3T" secondAttribute="bottom" constant="40" id="G1C-SH-ONS"/>
                                    <constraint firstItem="nk6-mF-h3T" firstAttribute="centerX" secondItem="PBs-dW-Koi" secondAttribute="centerX" id="MjW-Yu-9Bi"/>
                                    <constraint firstAttribute="bottom" secondItem="Exi-mx-rcW" secondAttribute="bottom" constant="8" id="R5m-2G-ZHN"/>
                                    <constraint firstItem="PBs-dW-Koi" firstAttribute="top" secondItem="GnA-uY-k8D" secondAttribute="top" constant="8" id="UZj-KF-b8H"/>
                                    <constraint firstItem="PBs-dW-Koi" firstAttribute="leading" secondItem="GnA-uY-k8D" secondAttribute="leading" constant="8" id="bhx-EO-I8M"/>
                                    <constraint firstItem="Exi-mx-rcW" firstAttribute="centerX" secondItem="nk6-mF-h3T" secondAttribute="centerX" id="gF2-Nw-sxy"/>
                                    <constraint firstItem="Exi-mx-rcW" firstAttribute="width" secondItem="nk6-mF-h3T" secondAttribute="width" id="glB-2g-ALO"/>
                                    <constraint firstAttribute="trailing" secondItem="PBs-dW-Koi" secondAttribute="trailing" constant="8" id="n5L-uV-uAN"/>
                                    <constraint firstItem="nk6-mF-h3T" firstAttribute="top" secondItem="PBs-dW-Koi" secondAttribute="bottom" constant="40" id="ppi-8s-Y5S"/>
                                    <constraint firstItem="nk6-mF-h3T" firstAttribute="width" secondItem="PBs-dW-Koi" secondAttribute="width" id="qFz-lA-ieI"/>
                                </constraints>
                            </scrollView>
                        </subviews>
                        <color key="backgroundColor" red="1" green="0.83234566450000003" blue="0.47320586440000001" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                        <constraints>
                            <constraint firstItem="V6X-c3-PaY" firstAttribute="trailing" secondItem="GnA-uY-k8D" secondAttribute="trailing" constant="20" id="0Ev-px-vRN"/>
                            <constraint firstItem="GnA-uY-k8D" firstAttribute="top" secondItem="V6X-c3-PaY" secondAttribute="top" constant="20" id="3sa-DD-wMb"/>
                            <constraint firstItem="V6X-c3-PaY" firstAttribute="bottom" secondItem="GnA-uY-k8D" secondAttribute="bottom" constant="20" id="Dji-Cc-aaB"/>
                            <constraint firstItem="GnA-uY-k8D" firstAttribute="leading" secondItem="V6X-c3-PaY" secondAttribute="leading" constant="20" id="ZKZ-mu-117"/>
                        </constraints>
                        <viewLayoutGuide key="safeArea" id="V6X-c3-PaY"/>
                    </view>
                    <connections>
                        <outlet property="tableA" destination="PBs-dW-Koi" id="Cnm-we-nuM"/>
                        <outlet property="tableAHeightConstraint" destination="BKq-4w-98u" id="6mm-8g-BQL"/>
                        <outlet property="tableB" destination="nk6-mF-h3T" id="yEs-cv-Zld"/>
                        <outlet property="tableBHeightConstraint" destination="Z9y-eh-Yju" id="oC8-9g-71b"/>
                        <outlet property="tableC" destination="Exi-mx-rcW" id="UhD-rh-9Kw"/>
                        <outlet property="tableCHeightConstraint" destination="qti-gs-wLU" id="ej2-mK-5YT"/>
                    </connections>
                </viewController>
                <placeholder placeholderIdentifier="IBFirstResponder" id="kfo-TI-SEb" userLabel="First Responder" sceneMemberID="firstResponder"/>
            </objects>
            <point key="canvasLocation" x="31" y="48"/>
        </scene>
    </scenes>
</document>