I am brand new to trying out an android app. I started to follow the online tutorial (https://developer.android.com/training/basics/firstapp/building-ui), but getting a bit
First and foremost, check to see if your dependencies match your SDK level. To check this, go to your app.gradle file and check every highlighted statement for version conflicts.
If this doesn't work, your next debugging step should be to restart your Android studio. Since the view shows in your component tree (and in your emulator), it ought to show in your preview. Previews in android studio lag sometimes due to various reasons (mostly machine related).
If it still doesn't show up after restarting, the problem might be a larger scale IDE issue and you should consider updating your question accordingly.
I hope this helps.. Merry coding!!