Blackberry 10.2 Cascades.
Is it possible to schedule a blackberry notification to fire at specific time(like on iOS), even when application is turned off? I successfully fired a notification while the app was in background as well as while in active state. The only alternative that comes to my mind is to schedule an event in the calendar, but I can't really respond to it by launching the application.
A present unfortunately the answer is no. With the release of 10.2.1 you could do this with a long-running headless application, but that seems like overkill. If you have a strong use case I would suggest you reach out to BlackBerry to request they add timer events to the list of triggers that can invoke short-running headless applications. This seems like a good fit for that paradigm, and BlackBerry have asked for developers to submit ideas for additional triggers.
Related
I have a simple app in Android, that uses some features like Services and Broadcast Receivers. It is a simple project, that uses SignalR to make a chat. A basic chat, where the service has the signalR connection and staying listening for any new messages or contact's status's updates.
Then, I have some broadcast receivers:
to start the service,
when receive a new message to add in the chatList
when receive a new contact online to update the contactList.
So it connects to a server that uses SignalR implementation, and do all the server job that is expected from a chatWebServer.
So, I'd like to re-write this app, using MvvmCross, so i could have a WindowsPhone, iOS and Android versions. I know the broadcast receiver could be changed for the Messages Services in MvvmCross, but the Android Services/ iOS Long Tasks/ WindowsBackgroundsTasks would be implemented as what in MvvmCross? Would be possible to have it implementation in Core project, so I can reuse it in all platforms? Can anyone help how would be it archtiecture?
Thanks in regard,
Gabriel Bastos
You will still need to rely on what the platform has available for you. So on Android you would still need to have a BroadcastReceiver or at least a Service which has the SignalR connection, otherwise it will not survive if the application is closed.
iOS and Windows is a bit of a different story, there you are not allowed to have stuff running in the background. So here you would probably need to use push notifications to notify of new messages. Although on Windows Phone you can have Scheduled Tasks or also called Background Agents here I think you can do something every 60 seconds at most.
On iOS you are out of luck you simply can't do stuff in the background unless you are using the built in Location Services or something like that.
MvvmCross does not do anything magically, nor does it allow to create a service which does something the platform does not provide.
I'm developing an iOS phonegap application which receives messages from a node.js/socket.io server. Everything works fine except when the application is "suspended". The user must re-activate the application to see incoming messages. Alerts throw only when the application is active.
Is there any workaround to throw alert messages even if the application is suspended.
Thanks in advance,
After a long research and some tests, it seems that it is impossible to keep an application running on background if it does not track localisation, use voip, play music and a limited number of other scenarios... at least on iOS.
I'm going to use APNS instead.
On iOS 8 you can wake up the app with a notification or by a time interval and then e.g. performFetchWithCompletionHandler
I am trying to take advantage of iPhone 4 multitasking feature. I want to run app in background and frequently send http request to send/receive data, is it possible?
Surprisingly, there is actually very little time-slicing going on in the "multi-tasking" iOS 4.x. What goes on instead is really just application suspend / resume. When an application is sent to the background upon the user tapping the home button, it will stop getting execute cycles after a short while (*).
(*) There are a few exceptions. Applications which declare themselves as "VoIP providers", location-based apps, and music apps can get background execute cycles, presumably only though to perform those very specific operations in response to corresponding events (like a "significant change in location" occurring). Some apps apparently try to stretch the rules and find undocumented or not-strongly-documented techniques to continue getting background execute cycles.
And the "requested running time" that Undeadlegion mentioned is limited in duration.
The reality is that on iOS4, applications are not allowed to run continuously in the background.
#Undeadlegion has suggested a plausible way to achieve your goal. To be more clear, take a look at my previous answer to a similar question at SO, iphone - Connecting to server in background
It is possible to request running time while your app is backgrounded.
See Multitasking Developer's Guide
Although, depending on the intent of your http requests, push notifications may be a viable alternative.
This may be necessary because you aren't providing audio, voip, or location services, so your app can't run in the background indefinitely.
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!
I'm developing a todo list application. I'm looking for any way to alert the user when a task becomes due, even if the app is not running. Is there any way to set the program to run at a specified time w/out user interaction? Or a way to bring up an alert anyway?
Edit: How can I add an item to the calendar?
No, not until the push notification service gets released.
Your best bet right now is allowing users to add reminders to the Calendar - without the push service, there's no notifications without your app running actively.
As has been made very clear by Steve Jobs himself, the iPhone SDK will NOT support background processes. In addition, there is no API to access the calendar on the iPhone.
If these things are important to you, you should file an enhancement request:
Apple Bug Reporter
But even once push is released, that won't enable you to have the application independently alert the user. You would have to run a server that would push notifications to people once a task is approaching due, which means you would have to have everyone's task list synced to your server.