Java Android Compare Times from String Format

Question

I have a String that contains a Time in the following format:

"hh:mm tt"

For Example you could represent the current time as "7:04 PM"

How can I compare this to the current time in the user's time zone to see if this time is less than, equal to, or greater than the current time?

I need this to be as efficient as possible since it will be executed in a Service. — zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
– zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz, Commented May 24, 2012 at 0:08
if you just have 7:04 PM and not the offset, how do you hope to compare it to an offset time in the users local timezone? Or are your times based off of a specific offset? — Mike McMahon
– Mike McMahon, Commented May 24, 2012 at 0:10
Personally then I would put the time into a 24hr format and just do the math directly on the hour/minutes/seconds...etc (whatever granularity you need) and then apply the offset to the result. — Mike McMahon
– Mike McMahon, Commented May 24, 2012 at 0:17
So you are recommending this as opposed to create Calendar() or Date() objects? — zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
– zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz, Commented May 24, 2012 at 0:19

Simon Dorociak · Accepted Answer · 2012-05-24 00:20:18Z

3

You can convert String to Date.

String pattern = "<yourPattern>";
SimpleDateFormat dateFormat = new SimpleDateFormat(pattern);
try {
 Date one = dateFormat.parse(<yourDate>);
 Date two = dateFormat.parse(<yourDate>);

}
catch (ParseException e) {}

It's implements Comparable interface so you should be able to compare them with compareTo()

Edit: I forgot but you know it but only for sure compareTo return -1, 1 or 0 so one.compareTo(two) returns -1 when first ist before second etc.

answered May 24, 2012 at 0:20

Simon Dorociak

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creemama · Accepted Answer · 2012-05-24 00:53:46Z

3

The following code elaborates on @Sajmon's answer.

public static void main(String[] args) throws ParseException {
    String currentTimeStr = "7:04 PM";

    Date userDate = new Date();
    String userDateWithoutTime = new SimpleDateFormat("yyyyMMdd").format(userDate);

    String currentDateStr = userDateWithoutTime + " " + currentTimeStr;
    Date currentDate = new SimpleDateFormat("yyyyMMdd h:mm a").parse(currentDateStr);

    if (userDate.compareTo(currentDate) >= 0) {
        System.out.println(userDate + " is greater than or equal to " + currentDate);
    } else {
        System.out.println(userDate + " is less than " + currentDate);
    }
}

answered May 24, 2012 at 0:53

creemama

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2 Comments

zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Over a year ago

Eclipse says that you must surround SimpleDateFormat.parse() with a try catch block.

creemama Over a year ago

Yes, this is true. In the code above, the main method throws a ParseException. In your code, just like in @Sajmon's answer, I expect you'll be surrounding parse with a try-catch block.

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