Implementing Android Content provider Insert(), using notifyChange() -

sorry, i'm not @ english.

i'm learning developing android apps in udacity. implemented insert() in content provider, , wonder. in code, there 2 different uris, returnuri , uri(past uri passed parameter).

@override public uri insert(uri uri, contentvalues values) {   final sqlitedatabase db = mopenhelper.getwritabledatabase();   final int match = surimatcher.match(uri);   uri returnuri;    switch (match) {     case weather: {       normalizedate(values);       long _id = db.insert(weathercontract.weatherentry.table_name, null, values);       if ( _id > 0 )         returnuri = weathercontract.weatherentry.buildweatheruri(_id);       else         throw new android.database.sqlexception("failed insert row " + uri);       break;     }     default:       throw new unsupportedoperationexception("unknown uri: " + uri);   }   getcontext().getcontentresolver().notifychange(uri, null);   return returnuri; } 

please pay attention bottom of code. in lecture, have use past uri in getcontext().getcontentresolver().notifychange(), not returnuri. 'note must use past in uri, , not return uri, not correctly notify our cursors of change.' don't understand this. used returnuri instead of past uri. passed test, , worked! have use past uri?