I have a Clock Alarm app that plays sound at certain time (Sending local notifications). Is it possible to play loop sound at certain time (when local notification comes) when app is placed in background ?
Just want to specify: I need to play loop sound, not only once
No. The reason why is because you won't be able to execute any code because of a local notification. One thing you can do, and it's totally up to you if this is something your app really needs to di, it to list this application as an audio application on the UIBackgroundModes key of your .plist file, and just change song that is playing at the time it has to. You can use a dispatch_after block to change the song at the time you want it to.
Make your app a long running background app as described in this link here
Related
I'm playing a silent music with AVAudioPlayer when user locks the screen, so that my timers won't stop.
However, when I play an iPod music with [MPMusicPlayerController applicationMusicPlayer], AVAudioPlayer stops,without receiving any call back.
Is there any way so that I can start [MPMusicPlayerController applicationMusicPlayer] playing without stoping AVAudioPlayer playing?
EDIT:
Thanks guys, this is the app I'm working on:
It is an Alarm app, this app allows user to lock screen while app is running,and when it is the time of the alarm, app can play iPod music to wake the user.Local notification can not use iPod music as alert sound, so I have to keep the app running while screen is locked.
If user quit the app, it will use local notification as alarm, whose sound is limited to files in bundle.
I can't use UILocalNotification as timer since when in screen locked status（in UIApplicationStatusInactive), app can't receive local notification generated by the system.
Apple has architected their backgrounding system to really limit things like this from happening. Essentially, there is no way for the you to keep the application running in the background unless it needs to be there. If you explain what you are trying to accomplish, maybe a better solution can be found but as good practice, never use random backgrounding methods to do other things. I am assuming that you might be using the faint music as a way to show something custom on the main screen, this is not a good idea.
Your app will get rejected if you play a silent audio.
Also as per apple's documentation https://developer.apple.com/library/ios/#documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/IPhoneOSClientImp/IPhoneOSClientImp.html#//apple_ref/doc/uid/TP40008194-CH103, notifications cannot have sounds (soundName) which play more than 30 seconds.
So you wont be able to release your app in the store.
I figured it out myself.
It is not calling [MPMusicPlayerController +applicationMusicPlayer] that stops AVAudioPlayer, but calling [MPMusicPlayerController -setShuffleMode:], I don't know why calling this would stop AVAudioPlayer, but it is where the problem lies in.
Thanks everyone, I think I should paste my complete code next time.
Well I am having two issues that i can't get to work, related to audio and calls.
The first one is to play a sound during a phone call. I don't want to play continuous music or stream anything, it is just a simple and short sound that the user will hear at one time during his call.
I have read some posts claiming that this is possible, and I even have an application that does so, but I can't get it to work. My app identifies the call using CTCallCenter and print the logs but never plays the sound or plays it after the app comes to foreground again. I have the .plist property of required background mode App plays audio.
The second issue, is to play the sound after some elapsed time. NSTimers doesn't work when on background mode, nor NSThread sleep on my background process or NSOperation. So how could I play this sound after say 10 seconds of the call?
Also, this behavior has to work also when the application is already on background mode. With CTCallCenter I am only getting the event when the application is interrupted from use, but I don't see any logs when i send the app to background and then begin/receive a call
.
If anyone could point me to the right direction I'll be really grateful.
I havent done this, but NSLocalNotifcation, schedule a notification to play when you app get the call to move into the background. I would expect this to work. Interested to find out if it does.
I'm working on a radio alarm clock, and i have some issues.
I am using local notifications for the alarms, so it has a gentle fallback if the app is not running.
I am well aware of the limitations of the device, and i know what i can and cannot do when the device has gone into background.
But my question is this:
I have seen other apps starting an audio streamer when i've locked the device. How is this possible? May this be inside an execution-timeframe?
How is the best way to implement this? Is it any way i can activate a streaming session when the device is locked?
Edit
To clarify: I know how i make audio play in the background. But the issue is triggering the audio-playback when an local notification or some other event fires.
One app that seems to do this, is Radio Alarm Clock. I haven't tried it for long period of times yet. But it seems to do this. A video demo of the app: http://www.youtube.com/watch?v=KJQiFOcdBWk
Have you already declared your background task?
Support for some types of background execution must be declared in advance by the app that uses them. An app declares support for a service using its Info.plist file. Add the UIBackgroundModes key to your Info.plist file and set its value to an array containing one or more of the following strings:
audio — The app plays audible content to the user while in the background. (This content includes streaming audio or video content using AirPlay.)
iOS App Programming Guide - Implementing Long Running Background Tasks
You can add this by clicking on your main project icon, then under the Info tab you can add "Required Background Modes" to the "Custom iOS Target Properties" section. "App Plays Audio" will be one of the three default values.
Big Edit With New Answer:
If everything else is already in order, you can keep your app running in the background using the UIApplication method
- (UIBackgroundTaskIdentifier)beginBackgroundTaskWithExpirationHandler:(void (^)(void))handler
detailed here: UIApplication Class Reference
with an example here: Hour 21: Building Background-Aware Applications
This allows you to run an instance of NSTimer which triggers your music player. The difference between this approach and UILocalNotifications is that this method never lets the app fully enter the background mode, the music player exists the entire time which subverts the need to create it from the background, which looks to be impossible.
There may be limitations to how long of a timer you can set, I haven't tested this past 14 minutes out.
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! :)
I am developing an iphone app which uses background audio (on an infinite loop) to continue playing after the app has entered the background.
My problem is I want to implement a "sleep timer" which stops playback after a specified period of time.
Is this possible? I have spent an hour looking for a method to do this with no avail.
EDIT: My current thought is to use a lower level API, the Audio Queue Services, and manually re-fill the queue with another instance of the loop during the AudioQueueOutputCallback. If the timer has expired I do not fill the loop. I'm assuming this should work since the documentation says audio callbacks are still fired when an app is playing multitasking background audio. Can anyone think of a better way or a reason why this wouldn't work?
While you queue sound data on the background your app remains fully functional and running as if it was in the foreground (well almost), so yes, you should just write a timer that stops the playback at a given time and it will be fired as expected.
Now to the second question: once you stop queueing things up, your app will be "frozen" until the user manually brings it to the foreground... So what you should do is start queueing audio data from the second file before the first one is done playing, and if you DO need to pause or stop, maybe a solution is to play 0 bytes (silence)?
I'm not actually sure this would be allowed in the App Store. An app is not allowed to execute at all in the background, with the exception of VoIP apps and push notifications.