swift - NSEvent.keyCode 到 Swift 中的 unicode 字符

Question

我正在尝试开发一个 macOS 应用程序，我需要监听按键事件。

我可以使用以下类来做到这一点:

import Cocoa

class EditorWindow: NSWindow {
    override func keyDown(with event: NSEvent) {
        super.keyDown(with: event)
        Swift.print("Caught a key down: \(event.keyCode)!")
    }
}

我能够得到每个字母的键码，例如A = 0 和S = 1。

但是，在这种情况下，关键代码似乎不太适合 Unicode 标量，因此我无法将这些关键值转换为 Character。

有什么方法可以将 NSEvent.keyCode 输出的 UInt16 输出转换为 Character 或 String?

Answer 1

NSEvent 有一个名为 characters 的属性:

var characters: String?

The characters associated with a key-up or key-down event.

Declaration

var characters: String? { get }

Discussion

These characters are derived from a keyboard mapping that associates various key combinations with Unicode characters. This property is only valid for key-up and key-down events. It raises an NSInternalInconsistencyException if accessed on any other kind of event object.

This property is set to an empty string for dead keys, such as Option-e. However, for a key combination such as Option-Shift-e this property is set to the standard accent ("´").

For a list of constants corresponding to commonly-used Unicode characters, see NSText.