i used the following code to upload image to server in background
var queue = dispatch_get_global_queue(QOS_CLASS_BACKGROUND, 0)
dispatch_async((queue), {
self.StartUploadProcess()//upload function
})
the above code run perfectly in simulator but when i test the application on my iPad it will stop the background execution when user click home button or open other application
please help me so i can run the application even the user click on home button?
The point of dispatch_sync() is to run the code in another thread synchronously. There is also dispatch_async() which runs asynchronously, that is, in the background.
From your question I assume you already know how to run it when you want to, just need to make it into an async call.
Related
I want to make a Flutter application which runs in the background and never stops. I tried so many methods for instance background process, foreground process, Notification and so on but I couldn't find any workable solution.
Can anyone help me with this?
Try this package
https://pub.dev/packages/flutter_background
Request permission to run in background
bool hasPermissions = await FlutterBackground.hasPermissions;
Then to run it in background use
bool success = await FlutterBackground.enableBackgroundExecution();
Please note this works only in android
Here is my code:
-(void) recordButton{
[[AVAudioSession sharedInstance] requestRecordPermission:^(BOOL granted) {
NSLog(#"value of the grant is :: %hhd", granted);
if (granted)
{
// perform operation recording
// perfrom some operation on UI(changing labels and all)
}
else
{
// do operation
}
}];
}
Problem is, when i run my app for the first time , after reset in the privacy and my app calls the above defined method, it creates trouble.
when My app run for the first time, allow/disallow microphones messgae(OS defined) method pops up.
when i click allow it displays the boolean(granted correclty). Goes inside IF correctly. Starts the recording correctly. but the UI freezes. and the second part of IF i.e changing label names, doesnt execute till , a timer (added by me stops the method and recording) executes.
PLease help.
I can sense that my 2nd part of the IF(changing UI label are not working in foreground), i.e. background work is working perfectly. Please Help, I am not expert. started iOS programing 2 months back.
I got the answer. my problem was, that when program reached If(granted) ,
it was performing the recording function but didn't performed on UI(changing labels and all).
The problem was, that the whole code was treated as a separate thread and was performed in background.
That's why recording was working properly(as it was a background process).
But UI(changing the labels) was a foreground task.
So For that, I had to execute the UI CODE under a thread that was on MAIN queue. And now it works perfectly.
AVAudioSession's requestRecordPermission callback is a background thread. Using code on the main thread inside a background thread causes issues (and most likely a crash).
You should call a method on the main thread to execute any post granted code. Using performSelectorOnMainThread: is an excellent way to make sure your code is running on the main thread (as explained here: execution on main thread).
I am having an issue with AVExportSession on exporting large files. App will crash during the export when app is in background state or in locked state. How to fix this?.
Unfortunately you will need to call cancelExport on your exportSession before the app goes into background state or if you're sure it will not take too long, you can register a background task in order to finish the export, which will give your app around a minute to finish before being kicked.
At least for iOS10 or later, the AVExport Session will return a failure with AVError.operationInterrupted when you app resumes. My way of doing it is to just tear everything down and restart the export once that is detected.
we can easily capture a view(screenshot) programmatically in iPhone.
But i am trying to capture screen automatically after every 5 seconds.that also, can be done.
But my main objective is , to capture screen, even if the app is closed, i.e in background.
Apple doesn't allow to background process to run for a long time, but can we do it for 5-10 min in background.
Capturing screen,even if the app is closed.Ofcourse user can close this function, within the app.
Apple might reject this, but is this possible ?
Regards
This is possible but it's not easy. You can register you app (via a .plist setting) as being a media app, this will allow it to run in the background. This is normally to allow media apps to continue playing music when the app is sent to the background. However if you are careful you can get it to do other thing in there too.
In your plist under "Required Background Modes" add a key "Item 0" and set it to "App plays Audio". This will mean you can do it.
You will then have to using AVAudioPlayer, play a silent sound that is say 5mins long, and then register one of your controllers for the AVPlayerItemDidPlayToEndTimeNotification notification. Then when this calls back, you can have your bit of code that, first takes a screenshot, and then starts the sound again.
This is the general concept, look somewhere like :
http://mobile.tutsplus.com/tutorials/iphone/ios-sdk_background-audio/
for how to set up the audio playing.
Just a note: APPLE WILL REJECT THIS!
If you are making an app for personal use only, this is fine, but will never make it to the app store.
Hoep this sheds some light on your situation! :)
When press the lock button in app,system will call :
-(void) applicationWillResignActive:(UIApplication *)application and
-(void) applicationDidEnterBackground:(UIApplication *)application
So how can I do to make my app only resignActive but not enter background,and I can run my timer when screen locked(Timer can't execute in background mode).
One method is set the property "Application does not run in background" in .plist to YES,it worked, but my app can never enter background again,however I want it will enter background when press the home button.
Update: I want to play some music in my app at a certain time,just like a music alarm,and I still want it works fine when the screen locked,because keep the screen on may waste a lot of battery,and I don't need to do any thing when user press the home button and exit my app.
Open your Info.plist file and add Application does not run in background. Set value to YES.
Application must have special privileges to do any processing in background such as Audio service/Voip service/Location service.
"I can run my timer when screen locked(Timer can't execute in background mode)"
you cannot run a timer in background which will keep running without using any tentrum and doing so...apple will not accept your application on appstore - that's the worst side if you are targeting appstore...
You can not prevent your app from entering the background. This is decided by the operating system (iOS) and is out of control from applications. However, from reading your updated question, I don't think this is what you need to do.
You can execute background tasks with [UIApplication beginBackgroundTaskWithExpirationHandler;] (see reference). If you want to have something happening after a certain interval, check out [UIApplication scheduleLocalNotification:].
Some services such as VOIP, Audio and CoreLocation are allowed to run in background. Using these for other than their intended purposes (for example, playing silent audio) may risk your app being rejected.
Note that there is nothing you can do to prevent your application from entering the background. It is just that some tasks are allowed to execute in the background. Because of this, you cannot do GUI operations and NSTimers will probably not fire (at least I know some cases where they don't).
It would help knowing what you want to run in the background in order to suggest a solution.
Unless you are playing audio BEFORE the move to background you cannot start audio playback when the app is moved to the background or the screen is locked (which has some weird specifics) suffice to say, its as if you were in the background without actually receiving the applicationDidEnterBackground notification.
The best you can do is schedule a local notification, but in this case your music is limited to 30 seconds and must be part of your application bundle.