and also I can't see my design part of xml code. Kindly let me know what we can do,
I tried:
- invalidating caches and restarting android studio.
- build -> clean project -> build -> rebuild project.

and also I can't see my design part of xml code. Kindly let me know what we can do,
I tried:

In my case, I verified that in File > Settings> HTTP proxy, I had checked the "no proxy" option. Then I created an exception in my antivirus for Android Studio and deleted the lines of proxy configuration of my gradle.properties file. Finally, I clicked on Sync Project with gradle files and it worked.