How to quickly format floating point number in Android game loop?

I'd like to display a millisecond timer value in a game.

String.format is hellishly slow on Android, so I can't use it. I currently use this:

long elapsedMillis = ...; //elapsed milliseconds
int whole = (int)(elapsedMillis / 1000);
int fraction = (int)(elapsedMillis % 1000);
StringBuilder sb = new StringBuilder("TIME:");
sb.append(whole);
sb.append('.');
if(fraction < 10)
sb.append("00");
else if(fraction < 100)
sb.append("0");
sb.append(fraction);
g.drawText(sb.toString(), ..开发者_如何学运维.);

but I think it could be done faster. Can you please guide me in the right direction? Thanks

related question

some ideas:

• use a static StringBuilder initialized with a large capacity
• use a native function
• have "TIME:" pre-drawn (I assume it does not move)
• keep the time value in milliseconds