Set min/max axis with date

Question

I have to show a line graph with the date in the X axis. I use the following method for show correctly the dates:

graph.getGridLabelRenderer().setLabelFormatter(new DateAsXAxisLabelFormatter(getApplicationContext()));

But I have a problem: I can't set the min and the max value of axis with the date because the methods setMinX and setMaxX accept the only double value, not date.

How can I solve this problem?