I have an application which performs a long running network operation. Now long running means approx 2 hour or more. Since this app downloads data from server and updates the ui as well it is required to keep is protected from iOS lock (screen gets locked and app is sent to background).
I have seen apps which can protect themselfs from being sent into background, for example angrybirds, you open any level and keep it idle, screen will not lock.
Do anyone having any idea how to do that?
[UIApplication sharedApplication].idleTimerDisabled = YES;
will disable the automatic screen lock.
To disable automatic screen lock in swift
Swift 4 & 5
UIApplication.shared.isIdleTimerDisabled = true
Related
When I pressing "home" button, app calling - (void)applicationWillResignActive:(UIApplication *)application, ok its good, but when I wait for a some time (10-15 mins), app starting from first loading screen, why? I have added:
[UIApplication sharedApplication].idleTimerDisabled = YES;
But not success. I think it goes to suspended mode, how do I prevent this? Thanks.
It means that your app has been killed by the system.
You can't prevent it completely, the system kills background apps when it needs more memory, but you can do something like this:
free as memory as you can when the app goes in background: doing this, when the system needs memory, your app won't be one of the first to be killed because its footprint is low.
Since you can't be sure that your app won't be killed, use state preservation / restoration: Link
EDIT:
since your app needs to reproduce audio in the background (as written in the comments) I give you some extra advices.
remember to register your app background mode (from this link: Multitasking guide) --> "by including the UIBackgroundModes key (with the value audio) in its Info.plist file"
the app continues to work in the background since it's playing audio, but when the audio is suspended the app is suspended too (it means that it can be killed). So, you must use state preservation to restore it when the user comes back.
Another extract:
"When the UIBackgroundModes key contains the audio value, the system’s media frameworks automatically prevent the corresponding app from being suspended when it moves to the background. As long as it is playing audio or video content, the app continues to run in the background. However, if the app stops playing the audio or video, the system suspends it."
You app has exited. If you want it to come back to where you left off you'll have to preserve the state somehow, check on launch, and then restore the state.
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.
I created application to download files. For downloading i use ASIHTTPRequest. When I start download big file, and lock my device, after some time my download stops, wi-fi disables and i see Edge icon instead of Wi-fi icon. When I unlock my device, Wi-fi icon appears in 1-2 seconds. My application is not in background! How to solve my problem?
Two things come to mind:
Firstly enable persisten wifi connection for you app: My iPhone app needs a persistent network connection...how to specify UIRequiredDeviceCapabilities?
Secondly make the app request background time when it goes into the background so the actual download can continue:
Continuing a long running process in the background under iOS4
I'm not sure if 10 minutes after locking the device if the app would count as running in the background or not.
I'd at least try enabling background downloading in ASIHTTPRequest:
[request setShouldContinueWhenAppEntersBackground:YES];
It might help and you've nothing to lose :)
You can also prevent the IPhone to lock the screen. It'll use more battery but will solve your problem:
UIApplication *myApp = [UIApplication sharedApplication];
myApp.idleTimerDisabled = YES;
I have developed an iPhone app which gets the microphone recorder inputs every second using NSTimer, calculate the amplitude of sound, and take appropriate action if required. I have noticed that when my iPhone gets locked, my application stops running(it doesn't fire the timer callback function). When I unlock iPhone, it start automatically. Could anyone please tell me how can I allow application responding when iPhone gets locked? Is there any other way around such that iPhone shouldn't get locked when my application is running? What should be Apple's recomendation on this?
I found this article but not sure it is correct way to do.
Thanks.
You cannot prevent timer from being stopped when application goes into idle state. Only one possible way is to disable idleTimer of the application.
application.idleTimerDisabled = TRUE;
//or
//Disable screen dimming if no user input occur on device.
[[UIApplication sharedApplication] setIdleTimerDisabled:YES];
I have used:
[UIApplication sharedApplication].idleTimerDisabled = YES;
in a number of Apps developed and running under iPhone OS 2.x and never had any problems with it. They were clock apps so needed to run constantly and ignore the iPhone's idle Timer setting.
However, trying to achieve the same with a new App running OS 3.0 (and which needs to be deployed under 3.0 as it uses some 3.0 APIs) I've found the idle Timer to be either ignored or inconsistent.
My App plays music from the iPod library and when the music is playing it auto-locks regardless of the above setting. But once you unlock it, it then doesn't auto-lock again unless you play music again, in which case it locks again after the iPhone auto-lock time setting.
I'm amazed no-one else has come across this as I imagine it would affect a large number of Apps.
Just to clarify:
1. The above code is in ApplicationDidFinishLaunching
2. I know that the phone won't auto-lock when testing from xCode regardless of settings
If anyone has any thoughts I'd be very grateful...
Our app uses the MPMediaPLayer. We also had the idleTimerDisabled=YES code in the ApplicationFinishedLaunching, which works EXCEPT if untethered, and there is already a current nowPlayingItem which is left playing (or unpaused, if paused at app startup). Obviously this is all with the Settings -> General -> Autolock set to some timed value.
By adding idleTimerDisabled=NO, immedately followed by idleTimerDisabled=YES in one of the other bits of code AFTER we had figured out what bit of music we would get playing seemed to solve the problem. Just setting it to YES was insufficient.. and subsequent queries had always indicated the correct value (YES).. so it appears the Apple code ignores the setting of the value IF there is a current piece of music and that is not changed by your code.. but does notice a change of value.
This is all under iOS 3.0.
Even in 2015, using iOS 8.2, this bug is still alive and kicking.
Here's my solution, using XCode 6.2.
iPhone - phone goes to sleep even if idleTimerDisabled is YES
Basically, even now, in 2015, the only way to safely make sure that the device doesn't go to sleep is to repeatedly call a piece of code to keep the device awake.
-(void)callEveryTwentySeconds
{
// DON'T let the device go to sleep during our sync
[[UIApplication sharedApplication] setIdleTimerDisabled:NO];
[[UIApplication sharedApplication] setIdleTimerDisabled:YES];
}
Sounds like a bug, file with Radar - I am not too surprised this has not been seen much as there are probably not a lot of apps that try to lock the screen open and play music.
Having same issue. It does work when the device is plugged in. You can press lock button on top, and my NSTimer fires later and causes a vibrate. However if the device is not plugged in pressing the lock button puts the device to sleep. Any solution would be greatly appreciated.
iCodeblog posted about the idletimer, I said it didn't work, and the person who develops 'cute clock' was nice enough to reply. You have to do a hack, play a 1 second or longer silent sound every 10 or so seconds with NSTimer. This keeps the device awake even if the user hits the lock button.
I develop Seconds - Interval Timer for iPhone and iPod touch and I've had no end of trouble with this. The idea of my app is that people create timers based on a number of intervals where each interval can have it's own playlist or track played.
In iOS3 I had the problem that I couldn't disable the idle timer by just setting idleTimerDisabled = YES. In the end I came up with the same solution as Neil whereby I would periodically set it to NO, then immediately to YES again. This seemed to work.
I'm now updating the app to iOS4 (I know, iOS5 is just around the corner...) and now I have the opposite problem. If the MPMediaPlayer changes track before the idle timer reaches it's limit it gets reset. I've just tested this by creating an interval in my app that was 55 seconds, my auto-lock was set to a minute. At 50 seconds the screen dimmed as it prepared to lock, but at 55 seconds when the music changed it went back to full brightness and then didn't lock as it should.
Overall, the implementation of this seems flakey at best.