Is it possible to have an App (running iOS4 on hardware supporting multi-tasking) which starts on iPhone startup and then regularly checks for online updates (every 15 minutes) and then refresh the badge, so the user can see how many unread items there are with-out having a push-server?
I was hoping this would be possible with iOS4 Programming Guide seems to suggest it is only possible to to this regarding Locations tracking, VoIP and playing background audio. There is also the possibility to do local-push notifications, but I don't see to find how to trigger a specific function that way.
Thanks in advance for any help!
edit:
Just having read a bit more, if the application is in the background/inactive state, and I son want to update the badge-number without displaying a message, is there an action triggered like didReceiveLocalNotification? There must be a way to schedule something on a regular basis (like email checking) without having to implement a full server-push-nitification system!
Is it possible to have an App ... which starts on iPhone startup and then regularly checks for online updates (every 15 minutes) and then refresh the badge
As you already figured out, the answer is no.
Related
I need to develop an enterprise app that monitors the network traffic. Basically it detects if the user is in wi-fi or cellular data and save the amount of bytes was sent and received in a period of time.
I saw an App at the AppStore that do exactly this job.
Detecting wi-fi or cellular data is quite simple using the Reachability Sample provided by Apple.
My problem is to keep monitoring the bytes sent and received while the app is in background.
As it is an enterprise App, I used UIBackgroundModes "voip" to avoid the app to be terminated.
I also installed the setKeepAliveTimeout method and I'm able to see the logs each 10 minutes, BUT only for 10 seconds after the method runs. I mean, setKeepAliveTimeout brings my App to run a Timer for 10 seconds each 1o minutes.
I'm thinking wether or not a task in background is the best solution for my problem.
I'll appreciate any comments.
EDIT: Ok guys. Thats the perfect way to do it.
First of all you must read this:
http://www.christian-fries.de/blog/files/tag-ios.html
I tried this and it works really fine.
All we need to do is to create a second thread detached from the main one. This way we have a continuos threading running forever. You must see the GCD docs at Apple's website also.
Second thing you should consider for an enterprise App is to set it up as a voip App, this way iOS will put your App running even after a reboot. It's a special behavior iOS has to keep voip Apps running.
Thats it guys.
I hope it can help you.
We dont have access to this data. There is no way to measure traffic.
The app you saw made an estimation (eg. 1mb/min) and after applicationWillEnterForeground. then you calc time x estimated-traffic and there we go.
Unfortunately there is no way to measure,
so I did a traffic-reset in settings and then i streamed exactly 1 min music. after a few repetitions I had my results. The problem is, that this works only fine with static traffic-processes like audio or video.
hope could help
endo
EDIT: look answer below!
Let me rephrase to make it clearer:
How can I have an "alarm" go off 20 minutes after my app has gone in the background?
Old question:
How can you have the simplest tast happen after 5-10-60 minutes on iOS? Essentially, have an NSTimer fire after a predefined interval.
I do "begin task", sleep( for some time ); and then "end task". However my app usually gets killed if I sleep for more than 5 minutes. I've seen posts around that mention that apps can stay alive in the background for a few hours, how exactly can that be achieved?
When your app goes to the background, the system will try to recollect as many as resources as you can give it to him like Images, nibs, etc. You have a notification for this. (– applicationDidEnterBackground:, etc)
After that, it will "sort" all the background living apps according the resources usage order. The app that uses more resources comes first.
Then when a new app comes to the foreground if the systems thinks it needs more resources than it currently has it will start killing background apps. using the above sorted list.
This means that the less resources you use in the background, the longer your app will live. BUT, there is no guarantee it will live long. (Everything depends on user usage). There is also no notification when it gets killed!, so you cannot assume your app will live for 60 min.
You probably want to read this Apple doc on how to do something in the background (with some time restrictions, off-course) and probably also UIApplicationDelegate class reference.
Hope it helps ;)
Just use a local notification
First ,this is my friends idea ,girls always use cell phone talk too much
every month they receive the billing will cost them a lot of money
they ask me is there any applications to calculate how long they dial out a month
or maybe can pop up a alert to notice them time is up,please hang up the phone
maybe 3 mins or 5 mins (some telecommunications provider offer free talk at first 3 mins )
So.......is it possible to use application to record your talking time and give you a notice ?
I'm just a new iphone programmer ,I have no idea about this ~
Even if this is impossible , still can share some information to me
It's help me to answer my friend
thanks :)
Using the wireless company's website would be the simplest way. If you really wanted a native iPhone app that would track time you could probably write one that utilized iOS's new multitasking abilities.
Essentially, the 10,000 foot view of the app would be something that a user would launch before making a phone call. When launched, they could start a timer (or delayed timer), move the app to the background (by tapping on the home button on a iDevice that supports background apps). The app's timer would continue to run in the background while the user makes their phone call.
I believe phone calls can be moved to the background as well, so users could go back to the app and check how much time they've been on the phone call.
Complicated, but doesn't require jail breaking. The implementation could be improved a ton, but that's the 1 minute, proof of concept, that you seemed to be looking for.
Was reading through the iOS4 documentation for multitasking, and couldn't figure it out.
I basically need to update the badge count on my app's icon after midnight each day as long as the app is running in suspended mode (with multitasking).
I know this has to be possible, just can't figure out the best way to do it.
Thanks.
iOS "multitasking" is very specific. There's an important distinction between states here:
Suspended: Your app resides in memory, but does not receive any execution time. This is really only useful for fast app switching.
Background: In a few particular cases, you can request that the OS to run your app in the background. (Playing audio, location, finishing a long task, voip.)
So, the short answer to your question is, "you can't."
Here are a couple useful links on iOS multitasking, such as it is.
Understand an Application's States and Transitions
Executing Code in the Background
You could use a UILocalNotification to set the badge (without an alert) but you can't increment the badge because you're app does not have the opportunity to execute any code when the notification fires.
You can schedule up to 64 notifications in advance, one at midnight for the next 64 days, each one setting a new badge number. It would make a lot more sense to schedule a repeating notification but since your app can't execute code it can't increment the badge number that doesn't work.
Ever since the first beta came out I’ve been trying to find out if “real” multitasking is possible — i.e. can you put a program in the background and have it hang on to a network connection indefinitely?
I’m thinking about IM or IRC apps, for example. I’ve compiled an app myself on iOS 4, and without changing a thing it appeared to stay running in the background, but for all I know it was just suspended to memory.
The docs say the best you can do is request up to 10 minutes, but in the developer presentation they showed off Skype sitting in the background and then notifying the user that a call was coming in. Does anyone know for sure how this all works?
It appears the answer is no. The API for Skype is a very special case, called the "voip" mode, and requires special behavior, such as marking the socket in use for VoIP.
You can receive alarm notifications in the background (such as time passed). The amount of time you are in the background running state is severely limited by the OS.
Android's background model is complete and in many ways much nicer.
Apple has a guide named "Supporting Multitasking In Your Applications" which you should be able to locate.
Apple's iOS 4 developer docs outline this all very clearly.
When your app is closed or switched away from, it is almost immediately "suspended", meaning the OS freezes the app's state. When the user switches back to your app, your code keeps running just where it kept off. You don't need to add any code to your app to do this, just compile it against OS 4.
The above is true in most cases. There are two reasons the "suspended" model may not apply:
1) If the device starts to run low on memory, the OS will start terminating suspended apps that haven't been switched to in a while, without warning. This is why it's in your best interest for your app to remember it's state as well, so if your app is terminated, then re-opened, the user doesn't really notice because it still returns to right where they left off.
2) Your app uses one of the "background" APIs. These are for audio playback, VoIP services, or location services. In this case, your app is allowed to continue running in the background but only has access to those APIs. Additionally, your app can designate certain long-running tasks as "background tasks" that need to be completed before the app is suspended or terminated, like uploading pictures to Flickr or rendering a video, etc.
The "background task" method doesn't cover pinging servers indefinitely, as there is a time limit for the task, after which it will be forcibly halted. Apps that need that sort of functionality are expected to implement push notifications, just as before.
That should clear this up. All in all I think it's a pretty elegant solution to multitasking on a mobile device.
iOS 4 applications can either be running or suspended. The operating system will try to keep as many requested applications as possible in memory, while all other applications are suspended.
Applications that run in the background can access features such as navigation, audio, and VOIP (but NOT instant messaging). So it looks like you might be out of luck.
-- PC World Multitasking on Apples iPhone 4
It is possible for apps to request background time. Read the docs. I would say it iOS is "controlled multitasking".
You can create a long running background task, I believe these can include networking features. Just have to set the background task flag on the work block.
https://developer.apple.com/iphone/library/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html
the OS can limit exactly how much time you get though... it will tell you when your time is up giving you a chance to cleanup nicely.
iOS 4 has "real" multitasking to some extend. There are two things to consider:
The UI event loop is single tasking. So only the front app executes on the UI event loop. Not a big deal: detach your main code form the UI event loop (maybe you need to redesign your app).
The OS "may" terminate your app if some criteria are met (e.g. low memory).
Currently one of these criteria is that execution time is limited to 10 minutes (real time not cpu time). However I expect this to change and see better criteria for background app termination (I hope to).
Apart from this you can have timers (event loops) in background.
There is no real multitasking in iOS 4.2 even. because apps will only be allowed to finish the task related to states..for small interval of time and then it will be in suspended state.. If you will set background task for long interval of time then... it will behave unexpectedly like no method will be called when you will try to run the app from anywhere..
You may be interested in this blog post that outlines how "multitasking" works in systems such as iPhone OS 4 and Android.
in fact u can do this, although it's not allowed by Apple. u gotta set up a toolchain in ur mac and use some unofficial SDK...
check http://code.google.com/p/iphone-backgrounder/ for more information
You should use the Push Notifications framework for the feature set you are creating!