I am new to iPhone apps developing. Just need my app to do some cyclic job (like a cron). Doing this that way prevent from overconsuming battery.
As I realized I could use /System/Library/LaunchDaemons, but I am not sure if I could use it without jailbreaking iPhone?
As you cannot write outside your designated application area on a non-jailbroken phone, you will not be able to access that path. Neither does Apple seem to encourage or support this kind of service as even keeping an active app in the background is impossible except for a few corner cases (location-aware, voip, ...) [on non-jailbroken devices on course].
You might consider (depending on the case) using Push notifications, specifically remote push notifications. These are issued from your server to apple servers which in turn notify the target phone whenever it is online. The user then has the option to dive into your app again which can display/handle the data. This is a method to resolve many cases where one might resort to polling, e.g. instant message scenarios. Of course this requires that it fits your application profile and that you have a server under your control that can handle the required task and that the app merely displays some information.
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I am thinking to make my own app like Find My iPhone app . But I am confused that whether apple allow developers to have access to play with the security or is there such Apple API's that can help us to include features as in the above app. Any suggestions?
Well I just can't comment because of low reputation. But people must give a reason to down-grade a question. Its quite a valid question.
Creating an app like this is semi possible. Due to the fact that you are not allowed to keep running in the background, except for certain special cases. Such as Music or a guidance app (navigation apps)
Your app can register to receive updates from the GPS location and process them.
The problem is it will use your gps all the time.
The find my iphone app is a combination of wifi location/sim card location/gps location.
It uses a combination of all these items which it has to keep track of your location as close as possible. Now back to your question, the fact that you cannot keep running in the background, will mean the app needs to stay open all the time (open I mean running, not necessarily onscreen). Not like the application from apple itself, which of course is allowed to go outside these developer restrictions.
The APIs exist for you to create the main functionality of this app. Core Location and APNS
When use A is looking for the location of user B, A would tell a server that it needs user B's location.
A push notification could fire up user B's app, at which point...
User B's location services would kick in, in the background,
Send this information to your server
Then update user A with another push notification.
We are going to create a life saving app. This app is made for those critical and emergency conditions when someone fall ill suddenly.
As this application is for emergency case, we need to make this app accessible even when the phone is locked.
Is there any way including public or private API, we can implement the feature?
Thanks,
iOS isn't designed to be a life saver, it's designed to make income for Apple (to be crude, because many things you think would be possible just is not)
There is also the reason with battery life, memory usage etc that needs to be restricted in a mobile environment where power is not unlimited.
You could however look at things like Push Notifications (read the docs). The app won't be "accessible" in the sense, but you can have a chance users will launch the app when you ask them to - they will actively have to push a "ok open the app" button.
I would suggestnlooking into gestures to perhaps overide the lock for your apps usage. Whether it gets approved by Apple is another story.
I currently sell a Mac-only productivity tool that uses visual and audio notifications to remind the user of certain events taking place.
I've started planning the iPhone and iPad versions of that Mac program and would like to be able to provide notification services from the Mac to the iPhone, e.g. instead of the Mac playing an audio cue, the iPhone could vibrate, etc.
I have so far done very little iPhone development and I'm not really sure how the various push notification services work. Is this easy enough to do? or is a "challenge".
A few more potentially relevant pieces of information:
there will be a Dropbox-based sync between the iPhone and the Mac versions, so there is also the possibility of "sharing" a file that would prompt some action
it might be acceptable as a first step to not have "background" notifications and require that the iPhone client is running
What authentication issues should I expect to deal with?
You'll need to implement APNs (Apple Push Notification Service) in both your app and your server.
To clarify a few things:
You'll need a server doing those transferring messages job between the user's Mac/PC and their iDevices.
Your server will decide when to push what kind of notification to which user's device.
After that, your server sends a message to Apple's APNs server, which will push that message on your behalf.
It's absolutely OK that your app can be in the background or even closed when the APNs message arrives at the user's device. The user will be guided by the OS to open your app.
If the user has explicitly disabled your app's APNs function in her/his device, or, if the user cancels the APNs alert when it arrives, your app won't be launched if it originally stays in the background or if it hasn't been open yet.
The user will be asked to enable (as you put it, authenticate) your app's APNs function by the OS in her or his device when your app is launched for the first time.
It's not a challenging task for an experienced iOS developer or an experienced PHP developer, since Apple's documents and APIs are pretty straightforward. However, configuration on the server side can be a little tricky.
I believe Stack Overflow already has tons of information on how to enable APNs in iOS apps. All you need to do is be specific in your question and do the search work beforehand.
Hope that helps.
How does Apple do polling of a phone's location remotely? Is there any API that allows an app developer to do the same with the SDK?
My guess is that they are private, undocumented and probably un-callable api's.
I couldn't imagine the huge security implications of having an external party/app be about to poll a phone location without the users consent.
An iOS device already maintains a connection to one of Apple's push servers if push is enabled, and the server has to know the device on the end of the connection (to determine the push notifications to deliver to it). The easiest way to build on this is to have the server say "tell me where you are!" as a push notification.
The device also hits Apple's servers for other reasons (App Store updates, captive login page detection), but it's less likely that the server can identify the device in these cases.
That said, you can do this with the user's consent:
Make your app a background "voip" app (<key>UIBackgroundModes</key><array><string>voip</string></array> I think)
At app launch, check that you can retrieve the current location (I'm not sure what happens if you do this while your app is backgrounded).
Maintain a "voip" connection to your server.
When the server asks the device for its location, ask Core Location for the location again and send it to the server. (I think you also need either "location" in UIBackgroundModes or you need to keep the connection active, possibly in both directions; the former may be easier.)
You won't be able to stop the "location services" icon from appearing in the status bar. The usual multitasking caveats also apply (your app can be killed if the phone runs out of memory; "voip" causes your app to be relaunched sometime later though).
I'm pretty sure if you do the "voip trick" your app will be refused from the store. It is only allowed if your app is actually a VOIP app, not just using it as a technique to circumvent background processing restrictions.
I am trying to determine feasibility of certain features required in a (potential) project. I am not (yet) looking for a how-to, just a can-do. I apologize for any vagueness and ignorance: the former due to an NDA that makes Apple's NDA look like GPL, and the latter due to the fact that I have no iPhone or MAC experience.
I do have a solid understanding of objective-c and interface builder (going back to NextStep) and some PDA development experience, so I'll probably understand the answers, even if my questions are naive. I have done a bit of browsing, so I know some buzzwords.
I can't go into detail about the actual project, but I have come up with a lame analogy.
a large number of users in the same room are asked to complete task(s) in the app (say a puzzle)
they are under supervision, but the monitor cannot watch them all closely
they are not allowed to leave the application until done.
they cannot send/receive phone calls or messages during the task.
the monitor receives notification of various steps during the task
the monitor is notified when the task is completed, or the app is exited
the app sends a heartbeat, so the monitor also knows if signal is lost
Jailbreak is not an option.
The app should also work on iPod Touch.
So the things I need to do that seem dicey to me are
can I turn off (or require the user to turn off) phone and sms but still be able send http to my server
can I prevent an app from being switched out (even if, say an alarm app triggers or the phone rings).
failing prevention, can I at least detect any of these events and notify my server.
failing notification, can I record the event for the monitor to check later.
The user will be aware (and in fact welcome) these restrictions. It's a trust issue - the user must not seek help or use a helper app to solve the puzzle, and wants the monitor (and other contestants) to know that he did not. It's feasible for the user to click on an "OK, I understand and approve" screen at the beginning, but not for each communication to the server.
The app would only communicate with a central server (run by my company) - the monitor would not be able to buy the server software, and the url's of the server would not be user (or monitor) modifiable.
Hey! This looks like an app for taking exams. Not what I am doing, but that would be cool too!
EDIT --
I changed the title and am adding a few more parts to the question, based in part on mmc's answer. The App may run in an offline mode that would have to do the following:
So using the exam analogy, the user off line experience would be something like this
Launch App
App download test questions, registers start time, etc.
Turn off phone (if app can't do it by itself)
Disable any app that might interrupt my App (can app do this?)
Resume and Take Test
Indicate test done (or finish last problem).
Turn on phone (if app can't) and restart App (if needed).
App uploads test results and log of any interruptions.
So the question becomes
Am I sure that I at least get to log any interruption I can't prevent
can I know the cause of the interruption (phone answered, alarm launch, user initiated)?
can the user be prevented from modifying the log
can I know what other Apps are running when I start? (to guard against a daemon that occasionally displays a hint or something.
I would still like to run with real time uploads, so a few other ideas come to mind.
If I can reliably detect and record that the phone or another app was used, that might be almost as good as preventing it.
Can the user prevent the phone from ringing even if it's on (eg. call forward + ringer off)
Can my app know if the ringer is off
Same question for sms messaging
If I can't block it, can the user just ignore (silent) call or message and not leave my App. Would my app know that?
Sounds like you might be better off doing away with the phone, and making it exclusive to the iPod Touch.
You've nailed your trouble spots.
There is no way to disable phone functionality, and at the same time maintain network functionality of any type (3G, WiFi, or bluetooth) If you disable the phone operations with Airplane mode, all of them are disabled.
There is no way to prevent the Home button from returning you to Springboard
You can notify a server of a premature app interruption (there is an applicationWillTerminate: method on your app delegate) but is not reliable. If the operation takes too long, your app will be forcibly terminated.
You could write to the local file system that a premature interruption happened, and this would be far more reliable, as this operation would be much faster.