Swift-从NSViewController捕获keydown

问题描述

我想在我的小应用程序中捕获关键事件.

I would like to capture keyevents in my little app.

我所做的事情:

class ViewController : NSViewController {
...
  override func keyDown(theEvent: NSEvent) {
        if theEvent.keyCode == 124 {
            println("abc")
        } else {
            println("abcd")
        }
    }

    override var acceptsFirstResponder: Bool {
        return true
    }

    override func becomeFirstResponder() -> Bool {
        return true
    }

    override func resignFirstResponder() -> Bool {
        return true
    }

...
}

会发生什么:

按下键时，会播放Funk音效.

When a key pressed, the Funk sound effect plays.

我看过很多帖子，都在谈论这是如何属于NSView和NSViewController无权的委托.但是keydown函数override自动在类型为NSViewController的类中完成，这使我相信这是错误的.

I've seen many posts talking about how this is a delegate the belongs to NSView and NSViewController does not have access. But the keydown function override auto completes in a class of type NSViewController leading me to believe that this is wrong.

推荐答案

Xcode 8.2.1•Swift 3.0.2

import Cocoa

class ViewController: NSViewController {

    @IBOutlet var textField: NSTextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        NSEvent.addLocalMonitorForEvents(matching: .flagsChanged) {
            self.flagsChanged(with: $0)
            return $0
        }
        NSEvent.addLocalMonitorForEvents(matching: .keyDown) {
            self.keyDown(with: $0)
            return $0
        }
    }
    override func keyDown(with event: NSEvent) {
        switch event.modifierFlags.intersection(.deviceIndependentFlagsMask) {
        case [.command] where event.characters == "l",
             [.command, .shift] where event.characters == "l":
            print("command-l or command-shift-l")
        default:
            break
        }
        textField.stringValue = "key = " + (event.charactersIgnoringModifiers
            ?? "")
        textField.stringValue += "\ncharacter = " + (event.characters ?? "")
    }
    override func flagsChanged(with event: NSEvent) {
        switch event.modifierFlags.intersection(.deviceIndependentFlagsMask) {
        case [.shift]:
            print("shift key is pressed")
        case [.control]:
            print("control key is pressed")
        case [.option] :
            print("option key is pressed")
        case [.command]:
            print("Command key is pressed")
        case [.control, .shift]:
            print("control-shift keys are pressed")
        case [.option, .shift]:
            print("option-shift keys are pressed")
        case [.command, .shift]:
            print("command-shift keys are pressed")
        case [.control, .option]:
            print("control-option keys are pressed")
        case [.control, .command]:
            print("control-command keys are pressed")
        case [.option, .command]:
            print("option-command keys are pressed")
        case [.shift, .control, .option]:
            print("shift-control-option keys are pressed")
        case [.shift, .control, .command]:
            print("shift-control-command keys are pressed")
        case [.control, .option, .command]:
            print("control-option-command keys are pressed")
        case [.shift, .command, .option]:
            print("shift-command-option keys are pressed")
        case [.shift, .control, .option, .command]:
            print("shift-control-option-command keys are pressed")
        default:
            print("no modifier keys are pressed")
        }
    }
}

---

要消除按字符键时需要发出的嘶哑声，您需要对视图进行子类化，请覆盖performPerEquivalent方法并返回true.

---

To get rid of the purr sound when pressing the character keys you need to subclass your view, override the method performKeyEquivalent and return true.

import Cocoa

class View: NSView {
    override func performKeyEquivalent(with event: NSEvent) -> Bool {
        return true
    }
}

示例项目

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