There are two ways of verifying.
1.Check IDE log¶
Set log level to Debug. If the User ID was correctly set, the IDE console will show the below log (for this purpose, the User ID is set as 1234-5678)
2019-11-11 16:05:21.641857+0900 Repro-demo-app[40072:1014116] INFO : Repro Set User ID: 1234-5678
2019-11-11 16:12:29.115 22902-22902/com.example.repro_demo_android I/Repro: Set user ID: 1234-5678
2.Check whether it can be added as audience¶
Open the audience dashboard, click add button and select specified ID, and enter the set User ID.
If the User ID was correctly set, you will be able to add the relevant device to the audience, as seen below.