Develop Reference

Android: Chronometer SetBase in minutes

Is there a way by which using the android chronometer class to set base of the chronometer in 15 minutes and from that period the times goes down until 0 seconds?
I have tried with setBase(60000) but this isn't work.

Check out this thread Android: chronometer as a persistent stopwatch. How to set starting time? What is Chronometer "Base"? as well as this thread Android - Get time of chronometer widget. Neither answers your question directly, but the nuggets there should lead you to an answer.

In general the chronometer works like this (if you would like to set the Base to a specific nr):
mChronometer.setBase(SystemClock.elapsedRealtime() - (nr_of_min * 60000 + nr_of_sec * 1000)))
what you are asking can be done through a countdown (http://developer.android.com/reference/android/os/CountDownTimer.html)
Or create your own countdown by using the chronometer like this (more work should be done cause i just wrote this and did not test it yet)
private OnChronometerTickListener countUp = new OnChronometerTickListener(){
#Override
public void onChronometerTick(Chronometer chronometer){
long elapsedTime = (SystemClock.elapsedRealtime() - mChronometerCountUp.getBase()) / 60000;
Log.v("counting up", elapsedTime);
// you will see the time counting up
count_down--;
if(count_down == 0){
mChronometerCountUp.stop();
}
// an int which will count down,
// this is not (very) accurate due to the fact that u r using the update part of the chronometer
// u just might implement the countdown i guess
// or 2 chronometers (one counting up and an other counting down using the elapsed time :p)
// just remember programming is creating ur solution to problems u face its like expression urself
};
};

http://developer.android.com/reference/android/widget/Chronometer.html
For set the base time you can use elapsedRealtime(), and you can output format with setFormat()

System.currentTimeMillis() work wrong

I need stopWatch and I used http://www.goldb.org/stopwatchjava.html
It did not work well so I tried write out the value every 1000ms:
stopWatch.start();
HandlerScrollBar.postDelayed(TtScroll, 1000);
private Runnable TtScroll = new Runnable() {
public void run() {
long time = stopWatch.getElapsedTime();
HandlerScrollBar.postDelayed(TtScroll,(long) 1000);
Log.d(TAG, Long.toString(time));
}
};
I can see value of time every second in CatLog and this is result:
Real time is max +5ms but in Column it is at least +3 seconds! How is it possible? It is the same with
new Date().getTime().
Is there some StopWatch class which will pass this test as expected?
Thank you.

If you are measuring elapsed time, and you want it to be correct, you must use System.nanoTime(). You cannot use System.currentTimeMillis(), unless you don't mind your result being wrong.
The purpose of nanoTime is to measure elapsed time, and the purpose of currentTimeMillis is to measure wall-clock time. You can't use the one for the other purpose. The reason is that no computer's clock is perfect; it always drifts and occasionally needs to be corrected.
Since nanoTime's purpose is to measure elapsed time, it is unaffected by any of these small corrections.I would suggest to pick the nanoTime() as it has better accuracy in those microcalculations.
for extremely precise measurements of elapsed time. From its javadoc:
long startTime = System.nanoTime();
// ... the code being measured ...
long estimatedTime = System.nanoTime() - startTime;

Seems impossible. I've never had System.currentTimeMillis() act that way. Also, you're logging out as Log.d() but the logcat you show indicates a Log.e(). You sure that's the right logcat?

Precision of delay

I have a problem with this code used for Android (Java)
handler.postDelayed(new Runnable(){
public void run(){
// Your code goes here...
}
}, 500);
If the delay is about 500ms then the program seems to repeat the task at 0.5s, but if I change to less than 100ms or even less it does not follow any more. I test the brightness change and for a while it can repeat the change of brightness at that rate, but then slow down and come back to normal flash rate again. It seems unstable. Do you have any code that give exact delay regardless of the load of the phone's CPU.
Many thanks

Not from Java, no; stock Java isn't a real-time system.
Timing precision is subject to the whims of the JVM and the OS's scheduler. You may be able to get incrementally more precise, but there's no guarantee of the kind of precision you're looking for.

You might be able to do something more precise if you use a CountDownTimer which has a periodic tick. Essentially you set it to count down for a period which can be hours if need be, and there are two methods one method is called on each tick, and the other at the end of the timer at which point you could start another one. Anyway you could set the tick to be very fast, and then only kick off the code at the delay point by check the actual time difference in the click. I think thats about the best you could do. Essentially inside the tick you would issue a signal if the right amout of time had actually passed. That signal would either kick off the thread or release something the already running thread was waiting on. What is the value of the CountDownTimer, I guess its just that you can do a very frequent polling, and elapsed time check. Although its not guaranteed, the time between the ticks you can set it to a high frequency and check/poll very frequently. This could lead to a smooth performance not unlike a realtime system. Its more likely to be accurate because its just issuing a signal and not taking up the resources of threading just to issue the signal. You might also try an IntentService to perform the tasks and just call startService(intentToIntentService) each call. See if the threading works better inside a service like IntentService which does queue them up I believe.
Date startDate = new Date();
long startTime = startDate.getTime();
// Tick called every 10th of a second. OnFinish called at Signal.
CountDownTimer ctDownTimer = new CountDownTimer(30000, 100) {
long startIntervalTime=startTime;
public void onTick(long millisUntilFinished) {
Date now = new Date();
long nowTime = now.getTime();
if ((startIntervalTime - nowTime) > 100)
{
issueSignal();
intervalStartTime=nowTime;
}
now=null;
}
public void onFinish() {
Log.d("MyClass", "Done") // Maybe start out.
}
}.start();

Android Dev: Timer not honoring dynamic interval period

im working on a audio profile switcher for android and as part of the entire project, i have a service that is running in the background using the following timer code:
timer.scheduleAtFixedRate( new TimerTask() {
public void run() {.....}, 0, nextUpdateInterval);
what im noticing is that the timer is not honoring the dynamically generated next update interval period...the nextUpdateInterval is declared as private static long which is initialized to 30000 (30 seconds) for the first run....then once a profile is found, i do some math and update the nextUpdateInterval...i have converted the nextUpdateInterval value back out to hours/minutes for debugging purpose, and the calculation is working as expected...like it shows me in hours and minutes, when the next timer execution should take place...
nextUpdateInterval calculation: long entirePeriodDiff = toTimeMiliseconds - fromTimeMiliseconds;
then once a profile is found, i calculate the elapsedTime like so: long elapsedTime = rightNowDate.getTime() - fromDate.getTime();
and then i update the nextUpdateInterval: nextUpdateInterval = entirePeriodDiff - elapsedTime;
one example scenario: Profile of 'Work' is set from 9AM to 4:30PM, the service/app is executed at 2:02PM (EST), my toast message is executing constantly and is acting as a count down telling me how much time is left...in this case 2:28 and decreasing...ideally this should not display until the 2:28 is up...any ideas?

As per android doc:
With fixed-rate execution, the start time of each successive run of a task is scheduled without regard for when the previous run took place. This may result in a series of bunched-up runs (one launched immediately after another) if delays prevent the timer from starting tasks on time.
I think that could be the reason, may be you need to consider alternative 'fixed period'

AS3 Delay Timer Execute and Start Timer

Hello I have a ActionScript 3.0 project and I have a timer that is running on 1000 millisecond intervals. I would like to delay this timer for 1500 milliseconds perform an action and start the timer again after the delay. I thought I could do this easily, but I'm having trouble, would it be better to stop the timer and perform the action and then listen for the action to be completed to start the timer again?
If you have time, I would appreciate the help.
Thank you,
Scientific

Assuming I understood your question, why not something like this? (UNTESTED CODE)
yourTimer.addEventListener(TimerEvent.TIMER, itIsTime);
function itIsTime(evt:TimerEvent):void {
yourTimer.stop();
yourTimer.reset();
if(yourTimer.delay == 1500){
//Do your stuff
...
yourTimer.delay = 1000;
yourTimer.start();
} else {
//Do your stuff
...
yourTimer.delay = 1500;
yourTimer.start();
}
}
Alternatively you could use 2 timers, but the idea is the same, after 1000 do one thing, after 1500 do something different, controlling when each timer goes off with the other timer's listener function.