I'm developing an android application and hit the problem with determining system first boot up time. I mean i need to measure how much time already passed from device first boot up.
I know about solution with listening for ACTION_BOOT_COMPLETED and save anything in SharedPreferences, but i need another solution, because this one does not work for some cases. Maybe there is any system property?
Use case (excerpt from discussion)
The filename of each file I receive from server includes a timestamp
taken from System.currentMillis()
I compare those timestamps in order to determine, which file the most current one is.
Now, the user changes system time a few months ahead.
I am still able to determine the most current file downloaded after user changed system time.
Now, the user changes time back to original setting.
The file downloaded on step 4 always wins when comparing timestamps.
The silver bullet to solve this problem would be a timestamp that counts seconds since first boot (after factory reset). Just like SystemClock.elapsedRealtime() but without reset after each boot. Unfortunately, the answers so far tell us, that this silver bullet doesn't exist.
However, many answers show a great variety of options how to tackle that problem. OneWorld123 commented each answer, how that suited his needs.
Maybe there is any system property?
Not sure about system property, but there is SystemClock class which provides API's to get system uptime:
SystemClock.uptimeMillis() which
Returns milliseconds since boot, not counting time spent in deep sleep.
You may also use SystemClock.elapsedRealtime() which
Returns milliseconds since boot, including time spent in sleep.
Hope this helps.
In case one needs to know when was the first time an Android device was booted,
The easiest method would be to have an application
that is installed in the factory image
that is configured to run during boot
that logs the current date & time into a sharedPreference on its first run
Subsequently any other apps that need to determine the first boot time of the Android device can lookup the appropriate sharedPreference during the lifetime of the device. (or until the device is factory-reset; at which point the pre-installed app would write the new date&time into the shared preference after a reboot.)
However if it is not possible to an pre-install an application on the Android device, then a couple of potential workarounds would be:
1. As a root/superuser
one would lookup the time-stamp of a directory/file that is known to get created on the Android device during first-boot.
2. As a regular app,
a simple workaround method using standard Android APIs would be to check for the installation-time of an appropriate system package that is known to get installed during first-boot.
/* This returns the last time a package was installed */
PackageManager pm = context.getPackageManager();
PackageInfo pInfo = pm.getPackageInfo(<app-package-name>, 0);
return pInfo.firstInstallTime;
3. Alternately as a regular app,
if we can rely on a specific package being updated one-time during first-boot (and never again) we can check its update-time as follows:
/* This returns the last time a package was updated */
PackageManager pm = context.getPackageManager();
ApplicationInfo appInfo = pm.getApplicationInfo(<app-package-name>, 0);
String appFile = appInfo.sourceDir;
long installed = new File(appFile).lastModified();
If we stick to the SDK, I don't know of a method providing this information directly; but there might be a way to derive this information from other resources. Again, if we stick to SDK, one "rather reliable" option is to use application usage statistics which Android OS saves during device lifetime. That is - the timestamp for a first "usage stats" ever saved.
This, though, clearly does not provide an exact "first boot time" timestamp, so it depends on whether some approximation is OK in your case. Generally, the problem with usage statistics is that Andriod aggregates it for periods distant in time - so, the older device is - the less accurate the date is. For example, for my current phone, first booted on Dec. 3 2014, aggregated usage statistics is first recorded on Dec. 21 2014 currently (for the record - it is Feb. 2016 by the time of this writing). (I have to admit though that I don't know how Android OS schedules the aggregation, and if it is just scheduled on Dec. 21 every year, or if it is indeed somewhat close to the first device usage - I guess it is easy to check with any other device.)
Following is some sample code showing UsageStatsManager usage, but it certainly would need more adjustments in order to address the fact of having more precision for more recent periods:
UsageStatsManager usageStatsManager = (UsageStatsManager) context.getSystemService(Context.USAGE_STATS_SERVICE);
Calendar year2013 = Calendar.getInstance(); year2013.set(2013, 0, 1);
List<UsageStats> stats = usageStatsManager.queryUsageStats(
UsageStatsManager.INTERVAL_YEARLY, // or adjust for "younger" devices to get more precision - so, you'll probably need several queries
year2013.getTimeMillis(),
Calendar.getInstance().getTimeInMillis());
// now, first element in stats (if it is present at all) will point to the "earliest" statistics saved *for this interval* (yearly in this case)
// use UsageStats.getFirstTimeStamp() to get first known/saved usage
Note also that, as documented in the SDK, UsageStatsManager requires PACKAGE_USAGE_STATS system-level permission, so you'll need to make user accept it in Settings first:
Intent settingsIntent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS);
startActivity(settingsIntent);
Hope it helps!
According to your discussion on: https://chat.stackoverflow.com/rooms/102325/discussion-between-ankitagrawal-and-oneworld , you need a monotonic counter to uniquely identify a dataset.
For that you can easily set a SharedPreference and increment this value every time you need a new identifier. When you require to know which is the newest file, just compare the identifiers. If it is an issue that this counter gets reset once the app is uninstalled, please refer to: In android is there any way to preserve SharedPreferences after an uninstall
A different approach that could be used, is to request a timestamp from an outside server.
Hope it helps ;-)
There are 3 methods in ANDROID SDK for these:-
public static long elapsedRealtime ()
Added in API level 1
Returns milliseconds since boot, including time spent in sleep.
Returns
elapsed milliseconds since boot.
public static long elapsedRealtimeNanos ()
Added in API level 17
Returns nanoseconds since boot, including time spent in sleep. Returns
elapsed nanoseconds since boot.
For #oneWorld Case:
You can use 2 approach:-
1) While writing check if some data has date above the current date then change the date of previous data to something less than current data and time,
so it will return correct latest data.
2) You can store the time on server and retrieve time from there and set it.
Related
I am currently developing an app that used for write some document and send them to a database. Issue is app need to get date and time automatically when form created and users can modify system date & time.
First, I search for solution on the internet, then one of the solutions is using a service that return time and later on count that time, so time can not be modified by user. This solution will not for this app because users can be in a place that do not have cell reception or internet access, so app need to work without internet access as long as sending data to remote database via internet.(date of form must be the time when form created)
Second idea is about network-provided time and time zone. If user want to change, he or she must disable those setting then modify time. I think when user want to write a form, app will check whether it is on or off. If it is of app will show an alert dialog which force them to activate those settings.
So I tested, I turned off wifi and cellular, turned off those setting, modified time and waited for a couple minutes. Then I turned on those setting and system showed correct time.
Also, after system corrected its date and time without network connection when I activated network-provided time and time zone setting, It made me think maybe app can get date from a place that user can not modify, yet I could not find information about this.
So I am looking for reliable method, and open for new ideas. If there was not I will implement second method.
Thank all of you who spared their time and read this.
And Second solustion will look like this:
private boolean isTimeZoneAutomatic(Context c) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
return Settings.Global.getInt(c.getContentResolver(), Settings.Global.AUTO_TIME_ZONE, 0) == 1;
} else {
return android.provider.Settings.System.getInt(c.getContentResolver(), Settings.System.AUTO_TIME_ZONE, 0) == 1;
}
}
Do you have any suggestion?
We have identified in our user base that since the last google fit app update there's been a dramatic drop in data, and since it began we have tried to identify the issue in our code. Giving the timing, we thought the version we were using ( 18.0 at the time ) was the problem.
Upgrading to SDK 20.0 did not improve the results, but stopped the data from stalling. currently we can assume 50-60% of the users connected to google fit trough the SDK are no longer corretcly retrieving data according to the (previously working) implementation. They are not lost, and they still send some bits here and there, but it's no longer what it used to be.
This graph showcases the timeline of events that lead us the conclusion that one of the sides must be doing something wrong.
The code examples below have been stripped of most data processing code for readability, but it is there.
Our Fitness client requests FitnessOptions.ACCESS_READ for all the types mentioned below, plus others depending on the App, every time it's initialised, either in foreground or background, making sure we only request those accepted by the user.
We can confirm the next data types no longer return any value when requesting daily total or local device daily total, but do return data chunks of the same period when requested in a non-aggregated read:
DataType.TYPE_STEP_COUNT_DELTA
DataType.TYPE_CALORIES_EXPENDED
DataType.TYPE_HEART_RATE_BPM
we also tried changing those possible to their aggregate counterparts, with no avail:
DataType.AGGREGATE_CALORIES_EXPENDED
DataType.AGGREGATE_STEP_COUNT_DELTA
This is our current getDailyTotal implementation, working before the update, and is written straight out as the examples on the developer site show:
Fitness.getHistoryClient(context, account)
.readDailyTotal(type)
.addOnSuccessListener {
Logger.i("${type.name}::DailyTotal::Success")
onResponse(it)
}
This currently returns 0 no matter the time of the day it's asked.
Then we have our complementary code, which emulates what getDailyTotal does in the insides, also as per developer site examples:
from: day start at 00:00:00, UTC+1
to: day end at 23:59:59, UTC+1
type: any DataType.
val readRequest = DataReadRequest.Builder()
.enableServerQueries()
.aggregate(type)
.bucketByTime(1, TimeUnit.DAYS)
.setTimeRange(from.time, to.time, TimeUnit.MILLISECONDS)
.build()
val account = GoogleSignIn
.getAccountForExtension(context, fitnessOptions!!)
GFitClient.request(context, account, readRequest) {
if (it == null) {
aggregatedRequestError(type)
} else {
Logger.i(TAG, "Aggregated ${type.name} received.")
}
}
The common result here is either 1) a null or empty result, 2) actually getting the result ( in the case of DataType.TYPE_STEP_COUNT_DELTA sometimes it happens ) or 3) a APIException code 5012, this datatype can't be aggregated.
We are using the single aggregate since the double, that could be called by (type, type.aggregate) has been deprecated since a couple versions already, although some developer site examples still use it.
The use ( or not ) of .enableServerQueries() does not modify the final result.
Finally we assume the worst and we request anything for that day no matter what and then we aggregate manually. This usually reports results, wether others did not. sadly those results are never conclusive enough to feel comfortable.
val readRequest = DataReadRequest.Builder()
.enableServerQueries()
.read(type)
.bucketByTime(1, TimeUnit.DAYS)
.setTimeRange(from.time, to.time, TimeUnit.MILLISECONDS)
.build()
val account = GoogleSignIn
.getAccountForExtension(context, fitnessOptions!!)
This tends to work but the manual processing of the data is complex given the intricate nested nature of datasets, buckets and the overall dataset structure.
We have also noticed issues when retrieving data that is clearly seen on the fit app, but doesn't appear on the SDK, for example, Huawei Health activities appearing on the App while the SDK returns only a subset of them, and the other way around, the SDK returning us data ( for example, a whole night worth of sleep sessions ( light, rem, deep... ), while the fit app shows that same sleep as a single Sleep block without any sessions.
Sleep session as shown in a third party app, with the same data the SDK returns us:
The same sleep session shown in the Google fit app:
As far as the documentation says:
For the Android APIs, read by data type and the Fit platform will
return the merged stream by default. This automatically includes all
data available to your app, including data written by other apps. You
won't be able to see a list of which apps or devices the data came
from with the Android APIs.
We believe that the merged stream is not behaving properly, not in real time ( which could be explained by a delay between the App showing the data directly from the backend and the SDK not having the data yet written ), but also not in a matter of minutes or hours of difference, sometimes never showing up.
To understand how we retrieve this data, we have a background WorkerManager CouroutineJob that every once in a while ( when the system lets so, given doze mode permissions, but what we would prefer (and ask so via WorkerManager configuration ) is once every hour or couple of hours, to keep the data up to date with the one displayed in the fitness app ), we request data from last update to last day's end day or/and we request today's daily total ( or up to the current time, depends on how far the "doesn't work" funnel we go, and also on the last update's date).
Is there anything wrong in our implementation?
has google fit changed the way it reports its data to connected apps?
can we somehow get more truthful data?
is there any way to request the same data differently, more efficiently? we are deeply interested mostly in getting daily summaries, totals and averages, rather than time buckets / sessions. We request both but they go to different data funnels covering different use cases.
There is no answer yet.
Our solution has ended up having a rowdy succession of checks for data and on every failure we try a different way.
I am using S3 Lifecycle Rule to move objects to Glacier. Since objects will be moved to glacier storage I need to make sure my application RDS is also
updated with similar details.
As per my discussion over this thread AWS Lambda for objects moved to glacier, there is no way currently to generate SQS notification to get notified about object being moved to glacier.
Also, as per my understanding currently Lifecycle rule will be evaluated once in a day, but there is not specific time when this will happen in a day. If there was i was planning to have a scheduler which will run after that and update status of archived objects in RDS.
Is there a way that you can suggest which will be close enough to sync this status changes between AWS & RDS?
Let me know your feedback or if you need more information on this to understand use case.
=== My Current approach is as per below.
Below is exact flow that I have implemented, please review and let me know if there is anything that could have been done in better way.
When object is uploaded to system I am marking it with status Tagged and also capturing creation date. My Lifecycle rule is configured with 30 days from creation. So, I have a scheduler which calculates difference between today's date and object creation date for all objects with status Tagged, and check if diff is greater than equal to 30. If so, it updates status to Archived.
If user performs any operation on object with status Archived, we explicitly check in s3 whether object is actually moved to glacier or not. If not we perform operation requested. If moved to glacier we initiate restore process and wait for restore to finish to initiate operation requred.
I appreciate your thoughts and would like to hear your inputs on above approach that i have taken.
Regards.
If I wanted to implement this, I would set the storage class of the object inside my database as "Glacier/Archived" at the beginning of the day it is supposed to transition.
You already know your lifecycle policies, and, as part of object metadata, you also know the creation time of each object. Then it becomes a simple query, which can be scheduled to run every night at 12:00 AM.
You could further enhance your application by defining an algorithm that checks if an object has transitioned to Glacier today, at the moment when object access is requested, it would go and explicitly check if it is actually transitioned or not. If it is marked as Glacier/Archive for more than a day, then checking is no longer required.
Of course, if for any reason, the above solution doesn't work for you, it is possible to write a scanner application to continuously check the status of those objects that are supposed to transition at "DateTime.Today" and are not marked as Glacier/Archive yet.
I wanted to learn more about the Android Services / Broadcasts, so I started a simple project, to create a battery monitoring app. It turned out pretty good, I'm using it for a few days now, but I want to add a new function: to show since when is the phone charging/discharging.
First I thought that I would create two static fields in my BoradcastReciever extension class, where I get and publish the data about the battery, one for the actual state (charging/discharging), and one for the time, when the change in state happened. This way, I could just subtract from the current time the last change, and know exactly since when is the phone charging/discharging.
But there is a problem with this solution: It won't show the correct data at first, when a user starts the app. I wouldn't make a big deal of it, but I saw that Android tracks this data somewhere, because inside my phone settings I found this information, so why take the hard way.
So my question is: is there an easy way to get from the Android system the date/time (no matter what format) of the last charging state change?
I looked at the BatteryManager reference but there are no constants named after what I seek, and which I could use, to get the information from the Intent of my receiver.
The Android OS tracks the connect/disconnect of a power source, but does not make this data accessible to apps. You have to record this all yourself, using intent filters.
The two intent filters to use are android.intent.action.ACTION_POWER_CONNECTED and android.intent.action.ACTION_POWER_DISCONNECTED; with these, you can monitor when the power source is connected and disconnected.
You can find information about this process explained incredibly clearly here. Another blog describing the process can be found here.
I currently have an Android application that displays a schedule for a ferry boat. The application can display the full schedule (just a giant list), but the selling point in the application is it will display when the next two ferries are departing and how long from the current time that departure is.
I am relatively new to Java and currently use large Switch() statements in my code. Basically it gets the current phone time and compares it to all of the times in the schedule at which point it displays the next two departure times and then calculates the difference between current time and the departure times.
I am sure that a switch statement is not the best idea for speed purposes as well as code changing purposes. For example if one time changes its a bunch of lines of code to go in and fix for that one time change. Also if the entire schedule changes everyone has to update their app for the time change to take effect. My ideal situation would be to store a file somewhere on my webserver that could be downloaded and inserted into a hashmap (I think is the correct term) that would load the new schedule if there was a time change.
Not sure how confusing this is, but it would be greatly appreciated if someone could explain how I might use a hashmap or something else you might recommend to get this task accomplished. Currently the variables are the two ferry terminals as well as the day of the week since the schedule changes per day (monday, tues-friday, saturday, sunday).
Below is a screenshot of the application so you can understand it if my post wasn't clear. Thank you in advance.
Screenshot:
Store the schedule objects in a sorted array. You can then binary search the array for the first value greater than the current time. You'll probably use some parent array consisting of the location and applicable day of the week.
You can easily write that kind of data structure to a file that is read & parsed by the application for updates instead of being compiled into the code.
Details of this? First, understand resources in Android. If no updated schedule exists, fall back to the default resource.
Second, use an HTTP head request to check if a newer file exists. If it does, parse, download & save state. Saving Android Activity state using Save Instance State.
Finally, XML is handy for data distribution, even if it's not fast. Everybody understands it and it's easy to update or hand off.
<ferry location=0 time=2045>
<day>1</day>
<day>2</day>
<day>3</day>
<day>4</day>
<day>5</day>
</ferry>
<ferry location=0 time=0800>
<day>6</day>
</ferry>
You will need something like a database to hold the schedule data. That will help you to seperate code from data. I'm not familiar with Android but i think there is a interface to sqlite database on the device.
Further, as this is an application on a small device you may connect to the schedule database on a server thru the internet connection. That way you have to maintain schedule data only in one place (on the server) and clients will use always up to date data.