Question

我有视图，我想在其中执行向右滑动手势。不幸的是我收到错误 EXC_BAD_ACCESS。有人知道这里有什么问题吗？请看下面的代码。

extension UIView {

    func addGestureRecognizerWithAction(nizer: UIGestureRecognizer, action:() -> ()) {

        class Invoker {
            var action:() -> ()
            init(action:() -> ()) {
                self.action = action
            }
            func invokeTarget(nizer: UIGestureRecognizer) {
                self.action()
                println("Hi from invoker")
            }
        }
        addGestureRecognizer(nizer)
        nizer.addTarget(Invoker(action), action: "invokeTarget:")
    }
}

class BugView: UIView {

    override func awakeFromNib() {
        super.awakeFromNib()

        var swipeRight = UISwipeGestureRecognizer()
        swipeRight.direction = UISwipeGestureRecognizerDirection.Right
        self.addGestureRecognizerWithAction(swipeRight) {
            println("Hi from the gesture closure")
        }
    }
}

Answer 1

最后返回true是对的。在上面的回答中，他通过建议使Invoker成为NSObject的子类，指出了我正确的方向。

但这不是我在代码中遇到的唯一错误。我发现当滑动发生时，用于处理事件的Invoker对象已经从内存中消失了。我认为关闭它的提法并没有像它应该的那样被捕获。现在我想出了另一种实现此功能的方法，我想与您分享：

class UIGestureRecognizerWithClosure: NSObject {  // must subclass NSObject otherwise error: "class does not implement methodSignatureForSelector: -- " !!

    var closure:() -> ()

    init(view:UIView, nizer: UIGestureRecognizer, closure:() -> ()) {
        self.closure = closure
        super.init()
        view.addGestureRecognizer(nizer)
        nizer.addTarget(self, action: "invokeTarget:")
    }

    func invokeTarget(nizer: UIGestureRecognizer) {
        self.closure()
    }
}

此代码段显示了如何使用代码：

var swipeRight = UISwipeGestureRecognizer()
swipeRight.direction = UISwipeGestureRecognizerDirection.Right

// swipeWrapper has to be defined as a property: var swipeWrapper:UIGestureRecognizerWithClosure?
// -> this is needed in order to keep the object alive till the swipe event occurs
swipeWrapper = UIGestureRecognizerWithClosure(view: self, nizer:swipeRight) {
    println("Hi from the gesture closure")
}

Answer 2

对于那些不喜欢关联对象和其他棘手东西的人，我有一个小型手势识别器，不需要任何麻烦。而且它不需要存储在某个地方。像常规GR一样工作。尽管它有一些限制-它是从UITapGestureRecognizer继承的，并且他只知道如何处理水龙头。但是我们经常需要所有的类型吗？我个人不是。

final class BindableGestureRecognizer: UITapGestureRecognizer {
    private var action: () -> Void

    init(action: @escaping () -> Void) {
        self.action = action
        super.init(target: nil, action: nil)
        self.addTarget(self, action: #selector(execute))
    }

    @objc private func execute() {
        action()
    }
}

用法示例：

    let gestureRecognizer = BindableGestureRecognizer {
        print("It's alive!")
    }
    self.view.addGestureRecognizer(gestureRecognizer)

如果出现了一些更有意义的行，请不要忘记[弱自我]。我们不想创建那些不死伙伴。

    let colorGestureRecognizer = BindableGestureRecognizer { [weak self] in
        self?.view.backgroundColor = .red
    }
    self.view.addGestureRecognizer(colorGestureRecognizer)

我似乎很方便从这些@objc衬里纯化我们的视图控制器，并使它变得更多..反应灵敏吗？

Answer 3

老兄，这是我的UIGestures的ClosureActionsHandler。我已经为UIView扩展了它，因此您可以在所有UIComponents上实现。这就是Git-link。快乐的编码真棒极客。

import Foundation
import UIKit

private var AssociatedObjectHandle: UInt8 = 25
public enum closureActions : Int{
    case none = 0
    case tap = 1
    case swipe_left = 2
    case swipe_right = 3
    case swipe_down = 4
    case swipe_up = 5
}
public struct closure {
    typealias emptyCallback = ()->()
    static var actionDict = [Int:[closureActions : emptyCallback]]()
    static var btnActionDict = [Int:[String: emptyCallback]]()
}

public extension UIView{

var closureId:Int{
    get {
        let value = objc_getAssociatedObject(self, &AssociatedObjectHandle) as? Int ?? Int()
        return value
    }
    set {
        objc_setAssociatedObject(self, &AssociatedObjectHandle, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    }
}
public func actionHandleBlocks(_ type : closureActions = .none,action:(() -> Void)? = nil) {

    if type == .none{
        return
    }
    var actionDict : [closureActions : closure.emptyCallback]
    if self.closureId == Int(){
        self.closureId = closure.actionDict.count + 1
        closure.actionDict[self.closureId] = [:]
    }
    if action != nil {
        actionDict = closure.actionDict[self.closureId]!
        actionDict[type] = action
        closure.actionDict[self.closureId] = actionDict
    } else {
        let valueForId = closure.actionDict[self.closureId]
        if let exe = valueForId![type]{
            exe()
        }
    }
}

@objc public func triggerTapActionHandleBlocks() {
    self.actionHandleBlocks(.tap)
}
@objc public func triggerSwipeLeftActionHandleBlocks() {
    self.actionHandleBlocks(.swipe_left)
}
@objc public func triggerSwipeRightActionHandleBlocks() {
    self.actionHandleBlocks(.swipe_right)
}
@objc public func triggerSwipeUpActionHandleBlocks() {
    self.actionHandleBlocks(.swipe_up)
}
@objc public func triggerSwipeDownActionHandleBlocks() {
    self.actionHandleBlocks(.swipe_down)
}
public func addTap(Action action:@escaping() -> Void){
    self.actionHandleBlocks(.tap,action:action)
    let gesture = UITapGestureRecognizer()
    gesture.addTarget(self, action: #selector(triggerTapActionHandleBlocks))
    self.isUserInteractionEnabled = true
    self.addGestureRecognizer(gesture)
}
public func addAction(for type: closureActions ,Action action:@escaping() -> Void){

    self.isUserInteractionEnabled = true
    self.actionHandleBlocks(type,action:action)
    switch type{
    case .none:
        return
    case .tap:
        let gesture = UITapGestureRecognizer()
        gesture.addTarget(self, action: #selector(triggerTapActionHandleBlocks))
        self.isUserInteractionEnabled = true
        self.addGestureRecognizer(gesture)
    case .swipe_left:
        let gesture = UISwipeGestureRecognizer()
        gesture.direction = UISwipeGestureRecognizerDirection.left
        gesture.addTarget(self, action: #selector(triggerSwipeLeftActionHandleBlocks))
        self.isUserInteractionEnabled = true
        self.addGestureRecognizer(gesture)
    case .swipe_right:
        let gesture = UISwipeGestureRecognizer()
        gesture.direction = UISwipeGestureRecognizerDirection.right
        gesture.addTarget(self, action: #selector(triggerSwipeRightActionHandleBlocks))
        self.isUserInteractionEnabled = true
        self.addGestureRecognizer(gesture)
    case .swipe_up:
        let gesture = UISwipeGestureRecognizer()
        gesture.direction = UISwipeGestureRecognizerDirection.up
        gesture.addTarget(self, action: #selector(triggerSwipeUpActionHandleBlocks))
        self.isUserInteractionEnabled = true
        self.addGestureRecognizer(gesture)
    case .swipe_down:
        let gesture = UISwipeGestureRecognizer()
        gesture.direction = UISwipeGestureRecognizerDirection.down
        gesture.addTarget(self, action: #selector(triggerSwipeDownActionHandleBlocks))
        self.isUserInteractionEnabled = true
        self.addGestureRecognizer(gesture)
    }


}
}

Answer 4

这是一个基于@ user1755189的答案的Swift 4.2方法，但我认为它的调用更简单。首先添加以下类：

<description>

然后，您可以像这样添加UITapGestureRecognizer：

<Snippet>

Answer 5

这里是imho不需要子类化的Simpelst解决方案，因此它非常通用。但是它需要关联的对象来存储动作：

extension UIGestureRecognizer {

typealias Action = ((UIGestureRecognizer) -> ())

private struct Keys {
    static var actionKey = "ActionKey"
}

private var block: Action? {
    set {
        if let newValue = newValue {
            // Computed properties get stored as associated objects
            objc_setAssociatedObject(self, &Keys.actionKey, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
        }
    }

    get {
        let action = objc_getAssociatedObject(self, &Keys.actionKey) as? Action
        return action
    }
}

@objc func handleAction(recognizer: UIGestureRecognizer) {
    block?(recognizer)
}

convenience public  init(block: @escaping ((UIGestureRecognizer) -> ())) {
    self.init()
    self.block = block
    self.addTarget(self, action: #selector(handleAction(recognizer:)))
}
}

这使您甚至可以对自己的子类使用跟随。用法：

    let tapRecognizer = UITapGestureRecognizer { recognizer in
        print("Hallo")
    }
    myView.addGestureRecognizer(tapRecognizer)

带闭包的UIGestureRecognizer

5 个答案: