swift - 如何在Swift中使用CGEventTapCreate？

有没有人设法使此功能在Swift中工作？

这是去年的引用SO帖子:Using CGEventTapCreate Trouble with parameters in Swift

苹果文档:https://developer.apple.com/library/prerelease/mac/documentation/Carbon/Reference/QuartzEventServicesRef/index.html#//apple_ref/c/func/CGEventTapCreate

这是CGEventTapCallBack的定义方式:

typealias CGEventTapCallBack = CFunctionPointer<((CGEventTapProxy, CGEventType, CGEvent!, UnsafeMutablePointer<Void>) -> Unmanaged<CGEvent>!)>

这是我编写块的方式:

let eventTapCallBackBlock : @objc_block
(CGEventTapProxy, CGEventType, CGEventRef, UnsafeMutablePointer<Void>) -> CGEventRef =
{ (eventTapProxy: CGEventTapProxy, eventType: CGEventType, event: CGEventRef, refcon: UnsafeMutablePointer<Void>) in
  return event
}

然后我用unsafeBitCast(eventTapCallBackBlock, CGEventTapCallBack.self)这样的回调参数调用了CGEventTapCreate

我收到了有效的CFMachPortRef，但是在运行时，在第一个事件上出现了访问冲突异常。它将“似乎”以其当前发布状态 swift 接近一个解决方案。

使用Xcode版本6.4

最佳答案

callback的CGEventTapCreate()参数是C函数指针，
在 Swift 1.x 中，不可能使用Swift函数参数来调用它。

但是，在 Swift 2 (Xcode 7)中，采用函数指针参数的C函数
可以使用闭包或全局函数来调用(但前提是
闭包不得捕获其任何本地上下文)。

例如，这是的完整翻译
Receiving, Filtering, and Modifying Key Presses and Releases
到Swift:

import Foundation

func myCGEventCallback(proxy : CGEventTapProxy, type : CGEventType, event : CGEvent, refcon : UnsafeMutablePointer<Void>) -> Unmanaged<CGEvent>? {

    if [.KeyDown , .KeyUp].contains(type) {
        var keyCode = CGEventGetIntegerValueField(event, .KeyboardEventKeycode)
        if keyCode == 0 {
            keyCode = 6
        } else if keyCode == 6 {
            keyCode = 0
        }
        CGEventSetIntegerValueField(event, .KeyboardEventKeycode, keyCode)
    }
    return Unmanaged.passRetained(event)
}

let eventMask = (1 << CGEventType.KeyDown.rawValue) | (1 << CGEventType.KeyUp.rawValue)
guard let eventTap = CGEventTapCreate(.CGSessionEventTap,
    .HeadInsertEventTap,
    .Default,
    CGEventMask(eventMask),
    myCGEventCallback,
    nil) else {
        print("failed to create event tap")
        exit(1)
}

let runLoopSource = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, eventTap, 0)
CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, kCFRunLoopCommonModes)
CGEventTapEnable(eventTap, true)
CFRunLoopRun()

的更新Swift 3:

import Foundation

func myCGEventCallback(proxy: CGEventTapProxy, type: CGEventType, event: CGEvent, refcon: UnsafeMutableRawPointer?) -> Unmanaged<CGEvent>? {

    if [.keyDown , .keyUp].contains(type) {
        var keyCode = event.getIntegerValueField(.keyboardEventKeycode)
        if keyCode == 0 {
            keyCode = 6
        } else if keyCode == 6 {
            keyCode = 0
        }
        event.setIntegerValueField(.keyboardEventKeycode, value: keyCode)
    }
    return Unmanaged.passRetained(event)
}

let eventMask = (1 << CGEventType.keyDown.rawValue) | (1 << CGEventType.keyUp.rawValue)
guard let eventTap = CGEvent.tapCreate(tap: .cgSessionEventTap,
                                      place: .headInsertEventTap,
                                      options: .defaultTap,
                                      eventsOfInterest: CGEventMask(eventMask),
                                      callback: myCGEventCallback,
                                      userInfo: nil) else {
                                        print("failed to create event tap")
                                        exit(1)
}

let runLoopSource = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, eventTap, 0)
CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, .commonModes)
CGEvent.tapEnable(tap: eventTap, enable: true)
CFRunLoopRun()

关于swift - 如何在Swift中使用CGEventTapCreate？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/31891002/