Color black = Colors.black; // example black color
String _storeColorValue = black.value.toString() ;
int value = int.parse(_storeColorValue);
Color color = Color(value).withOpacity(1);
var colors = { "NA":Color(0xFFFF9E80), "EU":Color(0xFF2196F3) [,…..,key_n:value_n] }
colors["NA"];....colors["EU"];