计算两个EditText之间的时差

Question

I have seen almost similar questions about this but my wont work as I want. Not at all in fact.

So I have been trying to calculate the time difference between two timestamps that I set with a TimePicker to two EditTexts.

Here is the code I dont get to work:

public void calcTime() throws Exception{
    String startTime = startworkFrom.getText().toString();
    String endTime = startworkTo.getText().toString();

    DateFormat format = new SimpleDateFormat("hh:mm a");
    Date time_1 = format.parse(startTime);
    Date time_2 = format.parse(endTime);

    long timeDiff = time_2.getTime() - time_1.getTime();

    System.out.println("Time difference" + timeDiff);
}

What is missing in the code?

UPDATE

I found the problem that is this line:

DateFormat format = new SimpleDateFormat("hh:mm a");

If I delete the ' a '. Also the value is really high. If I set 12:00 to 13:00 the difference should be 1.But I get a really huge value here. I will be using

Answer 1

The only problem now is if I start to work late at night and then stop working in the morning i will get a negative value but I guess there is a fix for that for another topic.

This should do it

String neg = "-"; 
    long timeDiff;  
    if(timeDiff.contains(neg)){ 
    timeDiff = time_1.getTime() - time_2.getTime(); }
else{ timeDiff =
    time_2.getTime() - time_1.getTime(); }
    System.out.println("Time difference" + timeDiff);

Answer 2

A solution to the negative values is to use the Math library. I did like this:

String a =""+Math.abs(diff/(60*60*1000)%24);