Reference
Google SMS retriever

Demo Environment:

AVD Emulator (with GooglePlay Store)

Steps

1. Run this demo

2. Click 'Test' to pickup a phone number
   (you can send the phone number to your server, then server sends SMS to the specific phone number)

3. See Android Studio Debug console, copy the hash code, paste it in next step. This hash code simulates server generated the one-time code. (thanks AppSignatureHelper.java, remove it before you publish your app)

4. Open emulator settings->phone->send message.
   SMS message format:
   <#> Your ExampleApp code is: 123ABC78 bMWGb1odbbw

5. SMS send to emulator, the smsRetrieverAPI verify SMS. Here's only two status you can get, success or timeout. if verify result is fail, nothing happened.