SimpleContract.kt

class SimpleContract : ActivityResultContract<Integer, String?>() {

    override fun createIntent(context: Context, input: Integer?): Intent {
        var intent = Intent(context, MyChildActivity::class.java)
        intent.putExtra("myInputKey", input)
        return intent
    }

    override fun parseResult(resultCode: Int, intent: Intent?): String? = when
    {
        resultCode != Activity.RESULT_OK -> null      // Return null, if action is cancelled
        else -> intent?.getStringExtra("data")        // Return the data
    }
}