Is it really possible that DecimalFormat is producing a comma version of the decimal on European phones?
Yes, absolutely. That's what it's meant to do, after all:
Creates a DecimalFormat using the given pattern and the symbols for the default locale. This is a convenient way to obtain a DecimalFormat when internationalization is not the main concern.
To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getNumberInstance. These factories will return the most appropriate sub-class of NumberFormat for a given locale.
Note that this isn't a matter of a "European version of Android" - it's just a matter of using Android in a context where the default locale uses ,
as the decimal separator.
If you want to use the symbols for a particular locale, but using a specific pattern, you could use:
DecimalFormatSymbols symbols = DecimalFormatSymbols.getInstance(Locale.US);
DecimalFormat format = new DecimalFormat("#.00", symbols);
Having said that, it's not at all clear what you're trying to do in the first place - why would you format and then parse a number? You should almost always avoid string conversions when you don't really need them. Why not just convert it directly? (We don't know what totalNumberOfCredits
is, which doesn't help.)