Convert a user inputted time to UNIX Time? [Android]

How would I convert a user given time, using the time picker would be fine, into UNIX time assumin开发者_如何学运维g the user inputted a time in the same time zone that they are currently in?

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You should use Calendar to convert values provided by the user to valid Unix timestamps

Calendar cal = Calendar.getInstance();
cal.set(2011, 9, 3);
cal.getTimeInMillis();