Develop Reference

Get same time between iOS and Android Devices

I'm trying to return time in milliseconds between both iOS and Android devices. I was hoping that since most devices sync their time with a networked server, they would be the same. However, I'm noticing they are not precisely the same.
I'm using this method for iOS:
[[NSDate date] timeIntervalSince1970]
and this for Android:
System.currentTimeMillis()
Is there a better way to try to return the same exact time across devices? I'm noticing these values can be off from each other by up to 2 seconds depending upon the Android device.
The use-case for needing this synchronized time is to display a looping animation that is also synced across the devices. So the animation would need to start at the same time, perform its animation for a set duration, and then loop again.
Thanks for any help.

You'll never get exactly the same time. The problem is that clocks aren't perfect, and that they aren't always synched to exactly the same time source at the same rate. Even if you synch to the same time source, the latency between when they process update messages will make a difference between them. 2 seconds is actually pretty good.
Time is tricky. Take 2 devices in perfect synchronimity. Fly from the US to Europe with one of them. They're no no longer in synch, and both are right- the general relativistic effects of traveling at high speed means one is now several milliseconds older than the other.
Basically what you want isn't going to happen. You'll have to settle for close enough. Although if you post why you need them so synchronized maybe we can give you some ideas.

Run vungle advertisments after some time

I'm having some problems to figure out how to run my add after a specific amount of time, let's say 5 minutes.
I have a basic app and the only possibility to add vunglePub.playAd(); would be after I handle the new answer of my app. Is there any possibility you could add in a timer set to 5 minutes each time and run vunglePub.playAd(); and then repeat it again?
Thanks in advance

Delighted to hear that you're using Vungle!
There are a couple of ways that you could achieve this:
1) Use any number of patterns in Java to keep a timer, and only call VunglePub.playAd() after certain amounts of time.
2) Use Vungle's built-in feature designed for this exact use-case! If you go to your app on the Vungle dashboard, click 'edit' and then hit 'advanced settings'. One of the options in there is the 'frequency' cap, which allows you set a minimum time, in seconds, between ad plays. If you set it to 300 seconds, then once you've called VunglePub.playAd() once, we'll ignore and attempts to playAd() until 300 seconds is up.
Option 1 may be more useful in some instances, especially if you want to action any other behaviour at the same time, but option 2 is probably the simplest to implement!
And if you run into any issues - hit us up at 'tech hyphen support at vungle dot com'.
David#Vungle.

Best Android threading technique for long-running tasks?

The thing is, that I have to keep a thread running for a pretty long time (it's really an indefinite time, could be 1 minute or even months), and it needs to update the UI about once every 1 milisecond...
There is the Executor, AsyncTask, Handler and the native Thread class... but which one is better for this case?
The problem with AsyncTask is that it is destroyed (or detached from the Activity?) like one hour or so after the Activity starts running on background, and the user could return to the Activity at any time just to find that it's not working (and even causing memory leaks), and the UI lags when changing to another activity or even pulling down the notification panel.
Natural Threads are even more laggy due to the post() method being called on the TextView every time I need an update to the UI (remember that I need to report progress about once every 1 milisecond)...
tl:dr
I'm developing a long running stopwatch, that can measure from miliseconds to days, weeks or even years. What is the best UI-intensive threading technique for this?
Could you please help me? Thanks!!
--- Edit:
Solved. It had to do something with system resources and the app moving to background. I just had to save the inital time and pauses as a bundle and load them when the app is started again. Thank you everyone!

I'm no Android expert, but I'm guessing that the reason why your AsyncTask gets cancelled is because the OS, being a battery powered OS, is deciding that a long running background task is a bad thing for battery consumption.
Having your program run a background thread for years is going to be a big disappointment for your users who will wonder why their mobiles run out of juice within a couple of hours. I suggest finding another way of doing your time measurement. What's wrong with using the device's real time clock?
I see little point in trying to update a GUI once every millisecond. The OS isn't refreshing the screen at that rate anyway, and no user on earth is going to notice anyway. Plump for once every 40ms at most.
And then there's the matter of accuracy. There's no point trying to measure time with millisecond precision on a device like an Android mobile over periods of hours, never mind days or months. Left alone the clocks and oscillators will be wrong by several seconds a day. The best one will be the real time clock, but even that is going to be pretty poor (they always are). Android is probably doing an NTP updated a couple of times per day, so there will be brief periods in a day when the local clock is close to being accurate (but even then it won't be millisecond accurate).
So even if you do manage to measure time with millisecond precision over months the answers you'll be displaying to the user are going to be wrong by several seconds. You'll be lucky to get within minutes of the actual elapsed time.
If your goal is just to have a stopwatch display rapidly updating when the application is in the foreground, just loop reading the real time clock and calculate/display the time since the stopwatch was started. Don't bother doing anything in the background, just sleep. When your app becomes foreground again resume the loop; the device's real time clock will have been ticking away all the time you're app is asleep, allowing you to calculate and display the time difference. This will be a lot simpler than trying to have a long running background thread, and it will also be more accurate than any other way you might choose (though still not millisecond accurate).

ActionScript 3: How can I keep an accurate BPM counter?

I'm looking to create a drum machine in ActionScript 3 (as an Adobe AIR Android app), which will keep to a user defined tempo (BPM).
I am struggling to find a way to keep the project in time, I have, at the moment, made it so that 5 different sounds are represented in rows of 8 squares, and the user can click each square to choose when to play that sound (hope this makes sense).
At the moment I am using Timer to keep the project in time, which is very laggy and inconsistent.

using timer is a bad idea for this, there I said it...
The issue is that the timer has a drift and fires several milliseconds later.
Try a simple test where you have a timer that executes every 500ms, and then compare the getTimer() count. What I have found in my experiments that the timer is continually off and it looks like it doesn't self correct. I've tried using a self-correcting timer, that changes the firing time based on the getTimer() difference since last run, but it's still not reliable. and anytime your processor's load picks up, the timer will be off anyway.
The correct way of dealing with this is to use byteArray data as a source for the sound. Based on the calculation of sampling resolution you can populate the stream with the data in advance, and the sound will play on time, pretty much guaranteed. I haven't gone as far as to create something that does this myself. But there are several libraries that you can utilize that can help you with this.
My top two decremented libraries are SiON and tonfall
you can see a sample of SiON here http://wonderfl.net/c/qf4b
and tonfall example at http://tonematrix.audiotool.com/
While I haven't tried them on android, I think either should work

Android - Efficiently update counters in views

In the app I'm writing I have a bunch of stats which I want to display for the user.
The stats include when a specific module was last run, when it will be run next, when the last communication with the server was made and then the next one is going to be.
As well as this there are stuff like memory usage (simple memory usage, not measuring the actual usage).
The memory usage etc can be updated every few seconds so that not a problem the but the times needs to be updated every second at least (for counters).
Since running every second (or even with 500ms period) results in irregular updates/skipped seconds I now run it at 300ms period.
I did notice however that my app began to lag when starting.
After some profiling it turns out it's the views that need to resize that is taking 70% of the time and the string formatter (for formatting the counter) takes pretty much the rest.
Apart from the CPU being used I see a lot of allocations, every few seconds I see a GC_CONCURRENT in the logcat.
Any tips on solving this efficiently?

Can you restructure it in a way so that the fiews require less resizing? Eg: set the width of your element to fill_screen or a DP size that is bigger than the longest string size

I solved the problem by writing my own timer that sleeps in short increments and only updates the view when a full second has passed.
This way the fire interval will be [period, period+sleepTime) which is acceptable when you choose a short sleepTime.
I've also changed so it says "5 minutes ago" and I have two timers, one that fires every minute and one that fires every second.