I have tried clean build and restart the android studio but its not working. Any solution please!! the preview is not showing any change.

I have tried clean build and restart the android studio but its not working. Any solution please!! the preview is not showing any change.

You can see the error by clicking that Red error symbol on right side upper corner in preview screen and share the error message here.
Just try to change the value inside Style.xml file from parent="Theme.AppCompat.Light.DarkActionBar" to parent="Base.Theme.AppCompat.Light.DarkActionBar". See if it works or not or share your error.
Thanks
Change your Dependencies version to alpha1
Like
implementation 'com.android.support:appcompat-v7:28.0.0-alpha1'
implementation 'com.android.support.constraint:constraint-layout:1.1.2'
implementation 'com.android.support:support-v4:28.0.0-alpha1'