Code the onTouchEvent function which enables the player to un-pause the game loop, move the ship and shoot a bullet at the invaders.

KotlinInvadersView.kt

// The SurfaceView class implements onTouchListener
// So we can override this method and detect screen touches.
override fun onTouchEvent(motionEvent: MotionEvent): Boolean {
	when (motionEvent.action and MotionEvent.ACTION_MASK) {

	// Player has touched the screen
	// Or moved their finger while touching screen
	MotionEvent.ACTION_POINTER_DOWN,
	MotionEvent.ACTION_DOWN,
	MotionEvent.ACTION_MOVE-> {
		paused = false

		if (motionEvent.y > size.y - size.y / 8) {
			if (motionEvent.x > size.x / 2) {
				playerShip.moving = PlayerShip.right
			} else {
				playerShip.moving = PlayerShip.left
			}

		}

		if (motionEvent.y < size.y - size.y / 8) {
			// Shots fired
			if (playerBullet.shoot(
					playerShip.position.left + playerShip.width / 2f,
					playerShip.position.top,
					playerBullet.up)) {

				soundPlayer.playSound(SoundPlayer.shootID)
			}
		}
	}

	// Player has removed finger from screen
	MotionEvent.ACTION_POINTER_UP,
	MotionEvent.ACTION_UP -> {
		if (motionEvent.y > size.y - size.y / 10) {
			playerShip.moving = PlayerShip.stopped
		}
	}

	}
	return true
}