An indicator can be added to a custom view based on the value of a roll-up field, regardless of the actual records in the view. The indicator will display as a badge if the roll-up field value is 1, and the formula IF(COUNTA(values)>0, TRUE(), FALSE()) can be used for the roll-up field. You can set this up by going to:
Tables
Click on a portal table
Go to Custom Views section
Click on a custom view
Set the rollup field in the Custom field to show badge in custom view button (Optional)