Android Account Transfer API: Where to get transferData for AccountTransferClient.sendData(accountType, transferData)?

Question

Im trying to implement the Android Account Transfer API which basically lets you transfer accounts for your app from an old phone to a new phone so the user won't have to login again when they use your app on the new phone.

However I feel like the documentation is missing information. Account Transfer API

When I call AccountTransferClient.sendData(accountType, transferData) to transfer accounts to the new phone, it doesnt tell me where I get transferData from. I tried looking at the AccountTransferClient docs for more info but it doesn't say much either.

Thanks!

Answer 1

Found the sample app https://github.com/android/identity-samples/tree/main/AccountTransferApi and apparently what they do is put account info in a JSON obj and then turn the JSON obj into a byte array (which is the transferData).

val jsonArray = JSONArray()
for (account in accounts) {
    val accountJsonObject = JSONObject()
    try {
        accountJsonObject.put(KEY_ACCOUNT_NAME, account.name)
        val password = accountManager.getPassword(account)
        accountJsonObject.put(KEY_ACCOUNT_PASSWORD, password)
    } catch (e: JSONException) {
        Log.e(TAG, "Error while creating bytes for transfer", e)
        return null
    }
    jsonArray.put(accountJsonObject)
}
val jsonObject = JSONObject()
try {
    jsonObject.put(KEY_ACCOUNT_ARRAY, jsonArray)
} catch (e: JSONException) {
    Log.e(TAG, "Error", e)
    return null
}
val transferData = jsonObject.toString().toByteArray(Charset.forName("UTF-8"))

Anyways highly recommend the sample app. The documentation is not clear enough!