Can we access the heart rate directly from the apple watch? I know this is a duplicate question, but no one has asked this in like 5 years. I know you can access it from the Health App but I'm not sure how "real-time" that will be.
If you don't expect 100% real-time.
You can use this one: HKAnchoredObjectQuery. I think it has a 300-500ms delay.
A query that returns changes to the HealthKit store, including a snapshot of new changes and continuous monitoring as a long-running query.
Related
Question 1. When a new heart rate sample is added to the healthkit, I want to read this sample immediately even when the app is running in background by using notifications method.Is this really possible, reliably?
So far, I tried the background fetch method to query for new heart rate sample added to the heathkit. However, the fetch does not fire reliably and it is very inconsistent. Hence my app does not receive the new added data immediately or sometimes nothing at all. I tried both simulated version and also on a real hardware.Debugging is also a challenge.
Question 2: I want to read the heart rate in my app when the phone is locked. Is this possible? Many threads says it is not possible due to encryption of data during locked period. But these answers seems to be old threads. Are there any definite answer to such a vital question?
There are many numerous threads without any clarity at all.Apple documentation is garbage. Such hinderance does not encourage beginners like me. Any suggestions would be appreciated.
I am trying to create a low-power watchOS app that will only periodically (every 5 minutes or so) need an updated but precise location. The key word there is need. The app certainly could provide better information if it were getting location updates consistently but the goal is for this app to be low power. That being said (and I am not sure if this is possible) if another app is constantly streaming location in the background it would be nice to get those updates too if that does not have extra battery cost.
Is there a way to only request location periodically? Is this actually better for the energy impact of the app?
I need to make an app that records heart rate data in near real time and send this data to a server as soon as possible.
First I took this approach: Watch os 2.0 beta: access heart beat rate
In fact it is working fine. There is new heart rate data in the HealthKit every five seconds. But now I have the problem that I can't sync that with a server.
My first approach was the Watch app. The watch was sending data to a server. That doesn't work because as soon as the screen turns black on the watch, it stops sending.
My next approach was to query the HealthKit on the iPhone every five seconds for new data. This works, as long as the app is in foreground.
Then I saw that there's some kind of background functionality that watches the HealthKit itself and revokes the app from background and you can do something.(enableBackgroundDeliveryForType) This doesn't seem to work for heart rate (the Apple Documentation says for things like steps this doesn't work, I guess heart rate is one of those).
I'm stuck now. Do you know how to it? I would need some background task that is executed every 5-10 seconds on the iPhone. That seems to be impossible
UPDATE
As noticed by #BootMaker, Apple made background mode available for HKWorkout apps in WatchOS 3, so it's working now. You have to run a HKWorkoutSession and this will keep your heartrate delivery in real time even when the app is in the background (dark screen on watch)
The closest you are going to be is while the watch app is open.
Why I'm stating this?
There are two HealthKit's Database (one at the iPhone and another at the Apple Watch). When they sync is arbitrary and decided only by the O.S.
The closest you are going to be to real time is when you don't have any password locking your screen in iPhone or Apple Watch.
Either way, there's no guarantee that the sync will happen every time a new measure is added to Apple Watch's HealthKit
The only way to force the Heart rate sensor into working in real time is via workouts or observer while your Apple Watch app is in FOREGROUND.
Background delivery is NOT available for Apple Watch apps.
Watch OS 2 request the sensor to measure automatically (in background) every 10 minutes minimum.
There's no other workaround, if you need real time for longer periods, or while the user is not using your app, you will need to use an specialized wearable.
If anyone still need to get heart rate or other data in real time. Use this solution:
Develop an apple watch app/extention
In watch app, using HKHealthStore, HKWorkoutConfiguration, HKWorkoutSession, HKLiveWorkoutBuilder to create an Workout. After create workout, your watch app will get heart rate in real time.
Using watch kit connection with WCSession to send data to iPhone app.
Enable background mode both in apple watch and iPhone.
I tested, even app terminated, we can still get heart rate (I used Local notification for posting heart rate data for debugging)
What I want to do:
I want to have my iPhone to frequently (formally defined later) upload my GPS location to a central server. I want to do this in the most battery efficient way.
Research I'm aware of:
Apple Documentation:
https://developer.apple.com/library/ios/#documentation/CoreLocation/Reference/CLLocation_Class/CLLocation/CLLocation.html#//apple_ref/doc/uid/TP40007126
Stack Overflow Links:
Response 1
Response: proof of existence; some other tool can do it
How to reduce iPhone battery consumption while using GPS
Response 2
Response: track only cell tower changes
iPhone GPS - Battery Draining Extremely Fast
iPhone running periodical process in the background - battery optimized way
Question
My question is a bit vague in that my definition of "frequently" is really dependent on what the battery life can tolerate. For example, if the battery can take updates of every 5 minutes, I'd like to do it every five minutes; if the battery could do this every 10 seconds, I'd like to do it every 10 seconds.
I really want to understand
the different ways (change on significant location, timer, background?) continuously uploading GPS locations can be implemented
advantages / disadvantages
approximately how long the battery life can last in each case
This seems like a fairly generic and common problem. Does anyone know of either:
an in depth analysis of the various methods
or if there is a single "optimal" way to do this?
[Moderators: feel free to mark this comment wiki. I'd love to just get lots of different answers + cost benefit analysis of them.]
Have a look at the Apple Documentation Here.
The significant-change location service offers a low-power location service for devices with cellular radios. This service is available only in iOS 4.0 and later and can also wake up an application that is suspended or not running.
It all depends on the use case. If the user will stay at a certain location and all you want to do is to track if he is leaving the country, tracking the significant location changing will be most suitable. However, this will not be precise enough for navigation apps.
One advantage of choosing the "Apple-Algorithm" is that they'll optimize it for you, if battery issues occur. (-:
we are creating a location-enabled app where users use this app to record certain events in the field.
The important part of the event data is when an event happened. This is no issue when user is online, but we also support situations when user is offline (by remembering & later syncing events).
There could be situations when users are offline and they change the time on the phone, so that event times are wrongly recorded.
So, what would be the best way to ensure we get a correct time, independent of user actions, given that device could be offline. Some ideas:
GPS time. Is it possible to acquire it?
Tracking system time changes made by user?
Any other idea?
Note: time does need second accuracy, approximately minute accuracy would be ok.
Note2: we are creating mobile apps for Android and iPhone, so I'm interested for generic solutions and also solutions that are specific to any of those two platforms.
I, personally, wouldn't worry so much about this scenario. The liklihood of someone intentionally changing the time on their Android (which periodically throughout the day syncs to a time server automatically) while offline seems low to me. That being said, the only way I could see compensating for this is to keep a service running in the background that keeps a running tally of the seconds passed since recording the location data offline. Once uploaded to your servers you could use the elapsed seconds to calculate a time offset from current UTC time. It's an awful lot to go through, but it would work.
GPS time is an interesting idea, but Android allows users of the SDK to send mock locations to their devices. I'm not sure you could reliably track changes to system time either, and even if you could you'd be capturing them after the fact without the current real time as context.
We use GPS times in our app for very similar reasons. Since our users are in different time zones and we want local times, we define from our server what time zone they are in at installation time (they don't move very far). Hadn't thought of the mock GPS locations, but you would need to be a fairly advanced user to do that.