Flexviewer uses Google maps as the basemap:
Before using a Google Map as the basemap, you must load the Google map code in Flex (a lot of code can be found on the Internet). If you load only Google Maps, it will be displayed successfully.
If your business layer is a dynamic MAP released by ArcGIS Server, you do not need to consider that dynamic maps can be dynamically projected into Google coordinates, however, if it is a tiled map, you need to consider more;
The wkid of the Google map is 102113, that is, the Web mokto. If your map is tiled, it is also 4326 (commonly used), that is, the geographical coordinate system,
Then you need to transform the map projection to the projection Coordinate System Web mocato (the same as your basemap Google projection), and then release the map, map slicing, note !!! Map slices cannot be classified as needed,
It must be fully graded based on the scale of Google Maps (or several levels should be reduced, but cannot be increased out of thin air ).
Flexviewer uses Google maps as the basemap