get the zoom level(Level ID) when using ArcGISTiledMapServiceLayer

[mavenmaven]

Hi:

I am using the ArcGISTiledMapServiceLayer and I meet two problems:

1 How to get the current Level ID of the map?

I can only get the resolution by

map.getResolution();

But it seem that the resolution by the method is not the fixed value defined in the server. For example:

With Level ID: 13, the resolution is :19.1092570712683

With Level ID: 14, the resolution is : 9.55462853563415

But the resolution I get from the method maybe 10.xxxxxx.

2 Is it possible to listen the "center_changed" event of the map?