swift - 在 Swift 3 中单击和双击 UITableViewCell

Question

我在 TableViewCell 上有 Storyboard segue，我用它在 didSelectRowAt 方法中单击单元格时转移到另一个 VC。现在我双击 TapGestureRecognizer 来处理单元格上的触摸。问题是单击时，segue 正在执行，而双击不起作用。双击可以很好地点击单元格。到目前为止，可以用我的代码以某种方式解决这个问题吗？或者我需要删除 segue 并分别处理单击和双击。感谢您的任何建议

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    let doubleTap = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTap))
    doubleTap.numberOfTapsRequired = 2
    view.addGestureRecognizer(doubleTap)
}

func handleDoubleTap(recognizer: UIGestureRecognizer) {
    let p = recognizer.location(in: tableView)

    let indexPath = tableView.indexPathForRow(at: p)

    if let _ = indexPath {
        tableView.deselectRow(at: indexPath!, animated: true)
        update(index: (indexPath?.row)!, isFinished: true)
    }

    print ("doubke")
}


override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "showSingleTask") {
        if let indexPath = tableView.indexPathForSelectedRow {
            let nav = segue.destination as! UINavigationController
            let destinationVC = nav.topViewController as! ShowTaskVC
            destinationVC.singleTask = tasks[indexPath.row]
        }
    }
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

    tableView.deselectRow(at: indexPath as IndexPath, animated: true)
    self.selectedTask = tasks[indexPath.row]
}

Answer 1

详情

• Xcode 10.2.1 (10E1001)、Swift 5

解决方案

protocol MultiTappableDelegate: class {
    func singleTapDetected(in view: MultiTappable)
    func doubleTapDetected(in view: MultiTappable)
}

class ThreadSafeValue<T> {
    private var _value: T
    private lazy var semaphore = DispatchSemaphore(value: 1)
    init(value: T) { _value = value }
    var value: T {
        get {
            semaphore.signal(); defer { semaphore.wait() }
            return _value
        }
        set(value) {
            semaphore.signal(); defer { semaphore.wait() }
            _value = value
        }
    }
}

protocol MultiTappable: UIView {
    var multiTapDelegate: MultiTappableDelegate? { get set }
    var tapCounter: ThreadSafeValue<Int> { get set }
}

extension MultiTappable {
    func initMultiTap() {
        if let delegate = self as? MultiTappableDelegate { multiTapDelegate = delegate }
        let tap = UITapGestureRecognizer(target: self, action: #selector(UIView.multitapActionHandler))
        addGestureRecognizer(tap)
    }

    func multitapAction() {
        if tapCounter.value == 0 {
            DispatchQueue.global(qos: .utility).async {
                usleep(250_000)
                DispatchQueue.main.async { [weak self] in
                    guard let self = self else { return }
                    if self.tapCounter.value > 1 {
                        self.multiTapDelegate?.doubleTapDetected(in: self)
                    } else {
                        self.multiTapDelegate?.singleTapDetected(in: self)
                    }
                    self.tapCounter.value = 0
                }
            }
        }
        tapCounter.value += 1
    }
}

private extension UIView {
    @objc func multitapActionHandler() {
        if let tappable = self as? MultiTappable { tappable.multitapAction() }
    }
}

用法

class MyView: UIView, MultiTappable {
    weak var multiTapDelegate: MultiTappableDelegate?
    lazy var tapCounter = ThreadSafeValue(value: 0)
    override func awakeFromNib() {
        super.awakeFromNib()
        initMultiTap()
    }
}

完整样本

ViewController.swift

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var tableView: UITableView!
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.dataSource = self
        tableView.tableFooterView = UIView()
    }
}

extension ViewController: UITableViewDataSource {

    func numberOfSections(in tableView: UITableView) -> Int { return 1 }
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return 10 }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell") as! TableViewCell
        cell.label.text = "\(indexPath)"
        cell.delegate = self
        return cell
    }
}

extension ViewController: TableViewCellDelegate {
    func singleTapDetected(in cell: TableViewCell)  {
        if let indexPath = tableView.indexPath(for: cell) { print("singleTap \(indexPath) ") }
    }
    func doubleTapDetected(in cell: TableViewCell) {
        if let indexPath = tableView.indexPath(for: cell) { print("doubleTap \(indexPath) ") }
    }
}

TableViewCell.swift

import UIKit

protocol TableViewCellDelegate: class {
    func singleTapDetected(in cell: TableViewCell)
    func doubleTapDetected(in cell: TableViewCell)
}

class TableViewCell: UITableViewCell, MultiTappable {
    weak var multiTapDelegate: MultiTappableDelegate?
    lazy var tapCounter = ThreadSafeValue(value: 0)

    @IBOutlet weak var label: UILabel!
    weak var delegate: TableViewCellDelegate?

    override func awakeFromNib() {
        super.awakeFromNib()
        initMultiTap()
    }
}

extension TableViewCell: MultiTappableDelegate {
    func singleTapDetected(in view: MultiTappable) { self.delegate?.singleTapDetected(in: self) }
    func doubleTapDetected(in view: MultiTappable) { self.delegate?.doubleTapDetected(in: self) }
}

Main.storyboard

<?xml version="1.0" encoding="UTF-8"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="12118" systemVersion="16E195" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="g2V-T0-sqD">
    <device id="retina4_7" orientation="portrait">
        <adaptation id="fullscreen"/>
    </device>
    <dependencies>
        <deployment identifier="iOS"/>
        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12086"/>
        <capability name="Constraints to layout margins" minToolsVersion="6.0"/>
        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
    </dependencies>
    <scenes>
        <!--View Controller-->
        <scene sceneID="tne-QT-ifu">
            <objects>
                <viewController id="BYZ-38-t0r" customClass="ViewController" customModule="stackoverflow_43153530" customModuleProvider="target" sceneMemberID="viewController">
                    <layoutGuides>
                        <viewControllerLayoutGuide type="top" id="y3c-jy-aDJ"/>
                        <viewControllerLayoutGuide type="bottom" id="wfy-db-euE"/>
                    </layoutGuides>
                    <view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                        <subviews>
                            <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="44" sectionHeaderHeight="28" sectionFooterHeight="28" translatesAutoresizingMaskIntoConstraints="NO" id="fQm-mQ-a9u">
                                <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
                                <color key="backgroundColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
                                <prototypes>
                                    <tableViewCell clipsSubviews="YES" contentMode="scaleToFill" selectionStyle="default" indentationWidth="10" reuseIdentifier="TableViewCell" id="nsF-ue-0bK" customClass="TableViewCell" customModule="stackoverflow_43153530" customModuleProvider="target">
                                        <rect key="frame" x="0.0" y="28" width="375" height="44"/>
                                        <autoresizingMask key="autoresizingMask"/>
                                        <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="nsF-ue-0bK" id="pT6-2N-oTC">
                                            <rect key="frame" x="0.0" y="0.0" width="375" height="44"/>
                                            <autoresizingMask key="autoresizingMask"/>
                                            <subviews>
                                                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Label" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="fEK-J3-oqH">
                                                    <rect key="frame" x="8" y="8" width="42" height="21"/>
                                                    <fontDescription key="fontDescription" type="system" pointSize="17"/>
                                                    <nil key="textColor"/>
                                                    <nil key="highlightedColor"/>
                                                </label>
                                            </subviews>
                                            <constraints>
                                                <constraint firstItem="fEK-J3-oqH" firstAttribute="leading" secondItem="pT6-2N-oTC" secondAttribute="leadingMargin" id="Vfg-Ij-f6c"/>
                                                <constraint firstItem="fEK-J3-oqH" firstAttribute="top" secondItem="pT6-2N-oTC" secondAttribute="topMargin" id="tc0-qJ-N1n"/>
                                            </constraints>
                                        </tableViewCellContentView>
                                        <connections>
                                            <outlet property="label" destination="fEK-J3-oqH" id="YBJ-tG-J5T"/>
                                        </connections>
                                    </tableViewCell>
                                </prototypes>
                            </tableView>
                        </subviews>
                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                        <constraints>
                            <constraint firstItem="fQm-mQ-a9u" firstAttribute="bottom" secondItem="wfy-db-euE" secondAttribute="top" id="8Vy-l8-jpB"/>
                            <constraint firstItem="fQm-mQ-a9u" firstAttribute="leading" secondItem="8bC-Xf-vdC" secondAttribute="leading" id="Wwr-ox-Qbd"/>
                            <constraint firstItem="fQm-mQ-a9u" firstAttribute="top" secondItem="y3c-jy-aDJ" secondAttribute="bottom" constant="-64" id="xJR-Uk-rbj"/>
                            <constraint firstAttribute="trailing" secondItem="fQm-mQ-a9u" secondAttribute="trailing" id="zxs-ED-Whb"/>
                        </constraints>
                    </view>
                    <navigationItem key="navigationItem" id="pLJ-Bz-NIm"/>
                    <connections>
                        <outlet property="tableView" destination="fQm-mQ-a9u" id="DhZ-jj-zmB"/>
                    </connections>
                </viewController>
                <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>
            </objects>
            <point key="canvasLocation" x="1079.2" y="137.18140929535232"/>
        </scene>
        <!--Navigation Controller-->
        <scene sceneID="w7e-Wj-oUR">
            <objects>
                <navigationController automaticallyAdjustsScrollViewInsets="NO" id="g2V-T0-sqD" sceneMemberID="viewController">
                    <toolbarItems/>
                    <navigationBar key="navigationBar" contentMode="scaleToFill" id="7qG-8v-S0O">
                        <rect key="frame" x="0.0" y="0.0" width="375" height="44"/>
                        <autoresizingMask key="autoresizingMask"/>
                    </navigationBar>
                    <nil name="viewControllers"/>
                    <connections>
                        <segue destination="BYZ-38-t0r" kind="relationship" relationship="rootViewController" id="yqZ-pK-Yf3"/>
                    </connections>
                </navigationController>
                <placeholder placeholderIdentifier="IBFirstResponder" id="tnz-x0-vDN" userLabel="First Responder" sceneMemberID="firstResponder"/>
            </objects>
            <point key="canvasLocation" x="140" y="137.18140929535232"/>
        </scene>
    </scenes>
</document>

结果