Provide the caller id for incoming call from my own app

I just barely wrote a tutorial on how to get this working. Check it out here: https://simplenexus.dev/2019/08/27/android-caller-id.html

The basics of how to get this working are:

AndroidManifest.xml

<provider
android:name=".callerid.CallerIDProvider"
android:authorities="@string/callerid_authority"
android:readPermission="android.permission.READ_CONTACTS"
android:enabled="true"
android:exported="true">
<meta-data
  android:name="android.content.ContactDirectory"
  android:value="true"/></provider>

CallerIDProvider.kt

private var userRepository: UserRepository? = null

private val uriMatcher = UriMatcher(UriMatcher.NO_MATCH)

override fun onCreate(): Boolean {
    context?.let {
        val userDao = UserDatabase.getDatabase(it).userDao()
        userRepository = UserRepository(userDao)
        val authority = it.getString(R.string.callerid_authority)
        uriMatcher.addURI(authority, "directories", DIRECTORIES)
        uriMatcher.addURI(authority, "phone_lookup/*", PHONE_LOOKUP)
    }
    return true
}

override fun query(uri: Uri, projection: Array<out String>?, selection: String?, selectionArgs: Array<out String>?, sortOrder: String?): Cursor? {
    when (uriMatcher.match(uri)) {
        DIRECTORIES -> {
            val label = context?.getString(R.string.app_name) ?: return null
            val cursor = MatrixCursor(projection)
            projection?.map { column ->
                when (column) {
                    Directory.ACCOUNT_NAME,
                    Directory.ACCOUNT_TYPE,
                    Directory.DISPLAY_NAME -> label
                    Directory.TYPE_RESOURCE_ID -> R.string.app_name
                    Directory.EXPORT_SUPPORT -> Directory.EXPORT_SUPPORT_SAME_ACCOUNT_ONLY
                    Directory.SHORTCUT_SUPPORT -> Directory.SHORTCUT_SUPPORT_NONE
                    else -> null
                }
            }?.let { cursor.addRow(it) }
            return cursor
        }
        PHONE_LOOKUP -> {
            userRepository?.let { userRepo ->
                val phoneNumber = uri.pathSegments[1]
                val cursor = MatrixCursor(projection)
                val user = runBlocking(Dispatchers.IO) { userRepo.getUser(phoneNumber) }
                user?.let { u ->
                    projection?.map { column ->
                        when (column) {
                            PhoneLookup._ID -> -1
                            PhoneLookup.DISPLAY_NAME -> u.fullName
                            PhoneLookup.LABEL -> u.phoneLabel
                            else -> null
                        }
                    }?.let { cursor.addRow(it) }
                }
                return cursor
            }
        }
    }
    return null
}