AndroidKeyboardShortcut.kt

/* Copyright 2023 Cedric Ferry.
   SPDX-License-Identifier: Apache-2.0 */

class MainActivity : ComponentActivity() {

  // activity top level interception of the keyboard events
  override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
    val ctrl_w = KeyShortcut(KeyEvent.KEYCODE_W, ctrl = true)
    val ctrl_r = KeyShortcut(KeyEvent.KEYCODE_R, ctrl = true)

    event?.let {
      if(ctrl_w.match(event)) {
        // action on CTRL-W
        return true
      } else if(ctrl_r.match(event)) {
        // action on CTRL-R
        return true
      }
    }

    return super.onKeyUp(keyCode, event)
  }
}
// Optional utility class to create keyboard shortcuts
class KeyShortcut(
  val key: Int,
  val ctrl: Boolean = false,
  val shift: Boolean = false,
  val alt: Boolean = false,
  val meta: Boolean = false,
) {
  // check if the KeyEvent match the shortcut
  fun match(keyEvent: KeyEvent): Boolean {
    return keyEvent.keyCode == key
            && keyEvent.isAltPressed == alt
            && keyEvent.isCtrlPressed == ctrl
            && keyEvent.isMetaPressed == meta
            && keyEvent.isShiftPressed == shift

  }
}