It doesn't seem that this question has come up before, so I'll ask it here: Is the expectation with the "shallow" copying of a Calendar via Calendar.clone() that the milliseconds stored become invalid?
I ask because the following chunk of code is failing:
public boolean someFunc(Calendar prevTime, Calendar proposal) {
int submissionMinuteThreshold = 30;
boolean isAfterMinTime;
...
Calendar min = (GregorianCalendar) prevTime.clone();
Log.i("PROJ", "1. Proposed time = " + proposal.getTimeInMillis() + ", min time = " + min.getTimeInMillis());
min.add(Calendar.MINUTE, submissionMinuteThreshold);
Log.i("PROJ", "2. Proposed time = " + proposal.getTimeInMillis() + ", min time = " + min.getTimeInMillis());
isAfterMinTime = proposal.after(min); // returns true even though min is 29 minutes later
I've experimented with the following settings:
proposal = 10:34 AM on 2014-10-25
prevTime = 10:33 AM on 2014-10-25
Log output is shown below:
After looking through the fields of min in the debugger, I see that add correctly sets the hour to 11, minutes to 03, and date to 2014-10-25, so it seems that add works correctly. However, when the comparison is performed, the milliseconds set in min are completely wrong, and that's what after (in the Calendar class) uses for a comparison.
As can be seen in the log output, the root of the problem with the milliseconds stored seems to begin with Calendar min = (GregorianCalendar) prevTime.clone(). Is there some other copy method that I should use so as to ensure valid comparisons later?
The problem was an incorrect initialization of prevTime, as suggested by prettyvoid.