Cannot reload AVD list: cvc-enumeration-valid: Value '280dpi' is not facet-valid with respect to enumeration

[monajalal]

Hi, can you have a look at my error?
Cannot reload AVD list: cvc-enumeration-valid: Value '280dpi' is
not facet-valid with respect to enumeration[ldpi, mdpi, tvdpi, hdpi,
xhdpi, 400dpi, xxdpi, 560dpi, xxxhdpi] it must be a value from the enumeration.

http://stackoverflow.com/questions/35808585/cant-run-the-sample-project-tango-app-in-android-studio