如何通过双击加速识别单个水龙头？

Question

我有一个带行的UITableView,我添加了单击手势和双击手势:

let doubleTap = UITapGestureRecognizer(target: self, action: "doubleTap:")
doubleTap.numberOfTapsRequired = 2
doubleTap.numberOfTouchesRequired = 1
tableView.addGestureRecognizer(doubleTap)

let singleTap = UITapGestureRecognizer(target: self, action: "singleTap:")
singleTap.numberOfTapsRequired = 1
singleTap.numberOfTouchesRequired = 1
singleTap.requireGestureRecognizerToFail(doubleTap)
tableView.addGestureRecognizer(singleTap)

有没有办法减少制作第一次点击和手势识别器识别它是单击而不是双击之间的时间.

我问这个是因为当我点击一下时,新的viewController显得很晚,给人一种应用滞后的感觉.

Answer 1

我在这个链接上找到了答案

快速版本:

class UIShortTapGestureRecognizer: UITapGestureRecognizer {
    let tapMaxDelay: Double = 0.3

    override func touchesBegan(touches: NSSet!, withEvent event: UIEvent!) {
        super.touchesBegan(touches, withEvent: event)
        delay(tapMaxDelay) {
            // Enough time has passed and the gesture was not recognized -> It has failed.
            if  self.state != UIGestureRecognizerState.Ended {
                self.state = UIGestureRecognizerState.Failed
            }
        }
    }
}

用delay(delay: Double, closure:()->()):

class func delay(delay:Double, closure:()->()) {
        dispatch_after(dispatch_time( DISPATCH_TIME_NOW, Int64(delay * Double(NSEC_PER_SEC))), dispatch_get_main_queue(), closure)
    }

Answer 2

完全实现了eladleb原始解决方案的Markus Swift 3 版本。

创建子类文件 UIShortTapGestureRecogninzer

import UIKit
import UIKit.UIGestureRecognizerSubclass 

class UIShortTapGestureRecognizer: UITapGestureRecognizer {
    let tapMaxDelay: Double = 0.3 //anything below 0.3 may cause doubleTap to be inaccessible by many users

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
        super.touchesBegan(touches, with: event)

        DispatchQueue.main.asyncAfter(deadline: .now() + tapMaxDelay) { [weak self] in
            if self?.state != UIGestureRecognizerState.recognized {
                self?.state = UIGestureRecognizerState.failed
            }
        }
    }
}

注意：添加时UIGestureRecognizer只需要 doubleTap 需要类型UIShortTapGestureRecognizer&singleTap.require(toFail: doubleTap)是必需的。

func addBoth (views: UIView, selectorSingle: Selector, selectorDouble: Selector) {
    let doubleTap:UIShortTapGestureRecognizer = UIShortTapGestureRecognizer(target: self, action: selectorDouble)
    doubleTap.numberOfTapsRequired = 2
    views.addGestureRecognizer(doubleTap)

    let singleTap:UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: selectorSingle)
    singleTap.numberOfTapsRequired = 1
    singleTap.require(toFail: doubleTap)
    views.addGestureRecognizer(singleTap)
}