Timer running inconsistent
asked 2014-08-30 14:45:25 +0300
Hi,
I realized that the Timer function is not really running constantly.
Timer {
id: ticker
interval: 1000
repeat: true
onTriggered: {
clock.time--
console.log(clock.time)
}
}
As long as the display is on it runes okay. Also if I turn off the display manually (there is a keep alive function running). The only issue is when the display dimmes down, then the last five seconds speed up and are done in 2.5. Any idea why?
You should never rely on interval functions to be precise (no matter which language); even if they generally are pretty close, there can always be external circumstances that make them unprecise and it sums up quickly. Better remember the start timestamp in a variable and calculate the difference to the current time on each tick to update the displayed time (or whatever you need to do with it).
tokaru ( 2014-08-30 19:45:52 +0300 )editLooking for a solution I found similar comments regarding timers several times. Too bad, the Timer function just look so simpel and it was so easy to get my code working.
FloR707 ( 2014-08-31 12:38:18 +0300 )editI guess I have to change my code and work with timestamps. If I do that I would still have the timer to update the view. What interval would you use to update the time stamps? 1000 ms or less?
Actually, it is nearly as simple, so instead of
tokaru ( 2014-08-31 16:24:37 +0300 )editclock.time--you could just do something like (pseudo-code)remainingTime = countdownDuration - (nowTimestamp - startTimestamp), assuming it is supposed to be a countdown timer. The interval depends on your needs: if you actually create a countdown displaying seconds, there is no need to go below 1000ms. From the performance point of view it could be much shorter, after all it is just a simple calculation and updating the user interface.