Timer to minutes : seconds : hundreds of seconds

Question

Possible Duplicate:
How to convert milliseconds to “hh:mm:ss” format?

I bet many people need a timer consisting of: minutes : seconds : hundreds of seconds. Clearly you start with:

` public TimeGame(){

    timer = new Timer(10, new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            counter++;
        }
    });
    timer.start();
}`

And then you need to call a methode that transforms this counter in : minutes : seconds : hundreds of seconds.

`private String timeTransfer(){

     minutes = counter/6000;
     counter = counter - (minutes*6000);
     seconds = counter/100 ;
     counter = counter - (seconds*100);
     milliseconds = counter;
     return minutes + " : " + seconds + " : " + miliseconds;
 }`

Yet i have a bug in my method. once it reaches 100 milliseconds it jumps back to 0. Normally it would have to put 0:1:0 , but it jumps back to 0:0:0. all Variables are declared private in the class.

So my question is does someone know a better method?

no duplicate, most timer converters are to hh:mm:ss – MrMe TumbsUp Jan 15 '13 at 23:30 — MrMe TumbsUp, Jan 15 '13 at 23:30
@MrMeThumbsUp Still duplicate as the concepts are the same. – nanofarad Jul 26 '13 at 15:02 — nanofarad, Jul 26 '13 at 15:02

score 5 · Answer 1 · answered Jan 15 '13 at 23:29

5

Suggestions:

Besides your math being off, a basic timer rule: do not trust the time interval of a Timer, ever. Instead store the initial System time, subtract it from the current System time and base your calculations on the real time, not on some artificial counter increment.
Also, you're using magic numbers, and need to avoid them. Instead use constants such as SECONDS_PER_MINUTE and MINUTES_PER_HOUR which will help you avoid careless math errors.

answered Jan 15 '13 at 23:29

Hovercraft Full Of Eels

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Also `TimeUnit` is good at converting... time units... So for example: `long SECONDS_PER_MINUTE = TimeUnit.SECONDS.convert(1, TimeUnit.MINUTES);` – assylias Jan 15 '13 at 23:32
@assylias: I never knew that even existed -- thanks! – Hovercraft Full Of Eels Jan 15 '13 at 23:33
1

[Joda-Time](http://joda-time.sourceforge.net/) – MadProgrammer Jan 15 '13 at 23:34
1

They said Java 7 would have Joda-Time equivalent 5 years ago. Now they say Java 8 will have it/has it. – Lee Meador Jan 15 '13 at 23:51
@LeeMeador It is still on track for Java 8. The final set of feature should be crystallised at the end of January. – assylias Jan 16 '13 at 10:49

Lee Meador · Accepted Answer · 2013-01-15T23:43:12.530

Here is the cannonical form of this code, written many times by many people over many years:

private String timeTransfer(){

     minutes = counter/6000;
     seconds = (counter % 6000) /100 ;
     milliseconds = counter % 100;
     return minutes + " : " + seconds + " : " + milliseconds;
 }

Another poster commented that using the timer this way is inexact. If you are just running this thing for a couple of minutes, the errors won't add up too much. if you are doing more that a few minutes you will want to use the system time to handle this.

First you store the current time when you initialize your counter:

long startTime = System.currentTimeMillis();

Then you periodically update the counter from the start time just before you return from timeTransfer()

if (milliseconds < 10) {
    counter = (System.currentTimeMillis() - start) / 10;
}

Thank you for posting clean correct formulas. 1+ – Hovercraft Full Of Eels Jan 15 '13 at 23:34 — Hovercraft Full Of Eels, Jan 15 '13 at 23:34

score 0 · Answer 3 · answered Jan 15 '13 at 23:29

0

Your method timeTransfer() modifies class member variable counter. Copy it to local variable in the beginning of method and perform calculations on it, for example:

    long counter = this.counter;

answered Jan 15 '13 at 23:29

Cozzamara

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Timer to minutes : seconds : hundreds of seconds

3 Answers3