I'm trying to build an alarm app that can fire an alarm while in locked-screen mode (the app is in the foreground, but the screen is locked). The alarm has to be triggered by a NSTimer not by uilocalnotification.
In iOS 4 I used the 'play silent sound every 10 seconds' hack to prevent the app from going to deep sleep and the timer events worked fine. However, in iOS 5 this doesn't seem to work.
Any ideas? Or this should work and I'm doing something wrong?
It seems that you actually can use the 'play silent audio' hack in iOS 5, but the audio has to be audible meaning you can't play it at volume set to 0.0.
You can use github.com/marcop/iPhoneInsomnia and set the volume to greater than 0, but it still doesn't work because the sound file is so short that the system kills your application before the timer is triggered and replays the sound. I solved this by setting the numberOfLoops of the audioPlayer to -1 (infinite repeat). Then it should work.
And you should also set the UIBackgroundMode plist key to an array of one string called "audio"
It's probably a dirty workaround, but in the past I have used the proximity sensor to turn off the screen instead of locking the phone. Simply place the phone upside down and the screen will turn itself off.
[[UIDevice currentDevice] setProximityMonitoringEnabled:YES];
This will allow you to retain full control over the device, while the screen does turn off.
Related
My app is checking some algorithm in the background, after something like 30 minutes
my application seems to be like close (iphone turn to sleep mode i think). I need the app
to run this algorithm as long as it is in the background.
Do you have any idea how to set this 20 minutes timer to recount by some action?
maybe NSRunloop or something else?
You can't reset this timer or continue to run in the background on a stock OS iPhone (except for a limited amount of time, or if your is legitimately of 3 types, VoIP, audio or GPS).
The user can reset this timer by bringing your app to the foreground, perhaps after a notification or something.
I have an audio app that is having some problems with the way iOS 5 has changed audio behaviors. When my app's audio is playing (AVAudioSessionCategoryPlayback), and a Clock.app alarm or timer is fired from the OS, the UIAlertView notification pops up, but without the audio alert. My application sound ducks fine to get out of the way of the audio alert, but the alarm app's audio alert does not sound.
Naturally, tons of support requests poured in over the iOS 5 change. I have solved this temporarily by setting kAudioSessionProperty_OverrideCategoryMixWithOthers which lets the alarm audio come through, but there are a few very undesirable side-effects when doing this:
Other app's audio can play with/over mine.
The remote control events are not routed to my app, but to iPod.app.
None of the above drawbacks are acceptable for my app's requirements. I have been hacking away at this for some time now but haven't been able to crack it. How can I setup my audio such that:
My app's audio still uses the AVAudioSessionCategoryPlayback category for background audio.
The Clock.app alarms still have their audio alerts make sound
The app still responds to remote control notifications
After writing this question I went to file a bug report on this. I created a small sample project that I thought would replicate the issue, but I could not replicate it! This caused me to dig in deep once again and try to figure out what was up here…
I fired up an iOS alarm, then I placed a break point in audioPlayerBeginInterruption: and traced through my code line by line in the debugger. I noticed that before my code ran (while I was paused in the debugger), the iOS 5 alarm was sounding! Luckily it still sounded even as I was stepping through my app, so I was able to figure out which pieces of code specifically caused it to stop sounding.
Part of my interruptionHandler is to (obviously) stop the internal audio of my app to let the interruption come through. I never thought to inspect this method before, but turns out the problem existed in there. My stop method would call prepareToPlay immediately after stopping to make resuming faster the next time.
[self.player stop];
[self.player prepareToPlay]; // <- iOS 5 alarm sound stopped here.
The docs state the prepareToPlay method
preloads buffers and acquires the audio hardware needed for playback, which minimizes the lag between calling the play method and the start of sound output.
Sounds reasonable, and this worked for lesser iOS versions. My hypothesis is that must have made a change to the Clock.app alarm system such that the new alarm sounds use the hardware, whereas before it used the software. This is what I think is causing the iOS 5 alarms to be silent in some apps.
Removing the prepareToPlay lines caused the alarm to sound without using kAudioSessionProperty_OverrideCategoryMixWithOthers, thus solving all my issues laid out in this question.
TL;DR
Remove the prepareToPlay calls from your stop sound code logic. It will take a microsecond longer to start later, but will allow interruptions to sound.
I have a small application which is much like a clock. It has been working great on IOS3, but now I am updating it to iOS4.
What I want to do in iOS4 is to let it play a sound any giving time. For instance, if I set it to play at 4.00 PM I want it to play a sound, a sound from the application not from the OS. This works if the app is launced, but if the user went back to the home screen I want the same to happen.
It is OK if a UIAlertView pops up istead of the application.
How can I do this?
Best regards,
Paul Peelen
Sounds like you'll need to use a local notification:
http://developer.apple.com/iphone/library/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Introduction/Introduction.html
and
http://developer.apple.com/iphone/library/documentation/iPhone/Reference/UILocalNotification_Class/Reference/Reference.html#//apple_ref/occ/cl/UILocalNotification
Read http://developer.apple.com/iphone/library/documentation/iphone/conceptual/iphoneosprogrammingguide/BackgroundExecution/BackgroundExecution.html.
What you want is UIApplication setKeepAliveTimeout:handler: which let you register a handler that will be called. You can use that to start playing audio. (Of course, compute the timeout when your app goes to background)
EDIT: Use UILocalNotification as andy said.
Two things you could possibly try under iOS 4.
Local Notifications can pop up an alert and play a short sound.
Another power hungry option is to register as a background music player, and play silence until time for the alarm to go off, then add your chosen sound to the "music" output. This will fail if the user switches to another media player app.
As of IPhone OS 3.0, MotionX GPS is able to keep recording a GPS track while in sleep mode. After you push the sleep button on top of the phone, the app continues receiving GPS coordinates and recording them. Does anyone know how they're able to do this? I'm only aware of the method to keep running audio while in sleep mode.
I found a great webpage that explains how to do it -
Cached link from Wayback machine
Original Link, now 404
You have to start a timer that plays a sound every 10 seconds. But the sound can be silent.
[UIApplication sharedApplication].idleTimerDisabled=YES should do it
I heard that the [UIApplication sharedApplication].idleTimerDisabled=YES will leave the screen's background light on, (after the user pressed the sleep button,) which will drain the battery.
But I have not tried this myself, so anybody with experiences correct this if it is wrong.
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.