I'm looking for a way to make the Chronometer in Android (preferably 1.6 and upwards) show 10ths of a second while counting up.
Is it possible to do this? If not, is there a free (and preferably open source) library that does the same? Failing that I'll write my own, but I'd rather use someone else's!
Is it possible to do this?
Not really. You could pass a format string that shows tenths of a second, but the Chronometer itself only updates every second. The update frequency is baked into the code.
If not, is there a free (and preferably open source) library that does the same?
The Chronometer source is available under the Apache License 2.0, so you can modify it to suit. Find all occurrences of 1000 and change them to 100, and you're probably most of the way there.
Bear in mind that this Chronometer can be used in an activity but not an app widget, since customized View classes are not supported by the app widget framework.