Update my app when it is in background

问题:

I want to update some data to my application. Consider the application is in the background state, it is neither Voip or Music or GPS. Is it possible to update/send data to the application which is in background?

NOTE: I dont want to notify the user so that the application becomes active.

Can anyone help me ??

回答1:

The answer is yes and no.

Apple does allow you app to complete a lengthy process in the background. But if you does not fall in the Voip, music or GPS category then you can't run in background.

If for example you want to send some data to a server, which could take some time, then you can mark that process to back executed until it is finished (or 10min. have passed).

You will find some about Executing a Finite-Length Task in the Background

There is not way to run timers or any thing like that in the backgroud, you can only finish a task you started before the app is backgrounded.

回答2:

The alert which is displayed is an inbuilt functionality. You can't do anything for that. If a notification is fired from the server and application is in background then the alert will be displayed. I have done a lot of search in past for this stuff.

回答3:

I have done this in one of my work. this is what i did.

when application enter : - (void)applicationDidEnterBackground:(UIApplication *)application

I send data to server using ASIHTTPRequest with property : [request setShouldContinueWhenAppEntersBackground:YES];

But after finished, i didn't do anymore connection or data manipulation. So, only the connection is running at background and not your app. you can't do much after the connection finish.

As @rckoenes was mentioned, you may not execute task too long.

回答4:

If you would like to update server data while your app is running in the background mode, the application should be active at that time. It can only be active if it uses "music, or voip, or location tracking", otherwise the app will be paused in background mode.

One way to avoid this is to develop your application, and to set it to use, for example, «location tracking». This will allow it to meet the requirements for active background process and you will be able to update server data.

Unfortunately, I do not know whether the app can pass app store approval with this set-up. However, if you are interested in this solution, you can find an example here.