I went through the ios sdk on github. But didn't understand the following parameters:
retrieveAndRank.searchAndRank( withCollectionName: collectionName, fromSolrClusterID: cluster.solrClusterID, rankerID: ranker.rankerID, query: "your-query-here", returnFields: "your-return-fields-here", failure: failure) { response in print(response) }
You can find the cluster ID and collection name on the Clusters screen.
You can find the ranker ID on the Performance screen.
For fields, I'd suggest
title,body.And the query is the question text that you want to search for.
Hope that helps!