macos - Swift - 从 NSViewController 捕获 keydown

Question

我想在我的小应用程序中捕获按键事件。

我做了什么:

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
    }

...
}

发生了什么:

按下琴键时，会播放Funk 音效。

我见过很多帖子都在讨论这是一个属于 NSView 的委托(delegate)，而 NSViewController 没有访问权限。但是 keydown 函数 override 自动在 NSViewController 类型的类中完成，这让我相信这是错误的。

Answer 1

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")
        }
    }
}

<小时/>

要消除按下字符键时发出的咕噜声，您需要对 View 进行子类化，请重写方法 PerformKeyEquivalent 并返回 true。

import Cocoa

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

Sample Project