// Create a Report Definition



ReportDefinition reportDefinition = new ReportDefinition();



// Set the Repo Date Range type as Custom Date



reportDefinition.setDateRangeType(ReportDefinitionDateRangeType.CUSTOM_DATE);



// Create. a date format as Google want date as string a specific format 



SimpleDateFormat dateFormat = new SimpleDateFormat("YYYYMMDD", Locale.getDefault());

      

// Create selector



Selector selector = new Selector();



// Add fields to selector



selector.getFields()

            .addAll(Arrays.asList("Id", "CampaignName");



// Set Min and Max date to the selector

      

selector.getDateRange().setMin(dateFormat.format(startDate));

selector.getDateRange().setMax(dateFormat.format(endDate));



// Add selector to Report Definition



reportDefinition.setSelector(selector);