Change default entry ID to your custom slug

GravityView Entry Slug Filter

<?php 
add_filter('gravityview_entry_slug', 'change_the_gravityview_entry_slug');    
/**   
 * Change the /123/ URL piece to /myslug/  
 * @param  string $slug Previous slug, default: "entryId"   
 * @return string           Change the new endpoint to "myslug"   
 */  
function change_the_gravityview_entry_slug( $slug ) {
      return 'myslug';  
}

}