I have an application that requires the iPhone screen to remain active (or not, depending on user choice). I've done this by disabling the application idle timer, which works fine and dandy until I start playing media via the MPMusicPlayerController. Due to a bug in the SDK, this then reenables the idle timer with no apparent way to disable it again.
My app flow is:
App starts
Screen stays on
<...time passes...>
Play audio file
Idle timer kicks in
Screen turns off
I have an empty audio file playing in the background to stop the phone going into deep sleep, but I'd really like to keep the screen unlocked too.
Has anyone managed to figure out a workaround for this?
I had a similiar problem, and found a fix for it. The fix might work for you too:
I call a method periodically (every 10 seconds), which sets idleTimerDisabled first to NO, then to YES.
- (void)calledEveryTenSeconds
{
[UIApplication sharedApplication].idleTimerDisabled = NO;
[UIApplication sharedApplication].idleTimerDisabled = YES;
}
Only setting to YES alone does not fix the problem. It seems the property has to change first to be recognized by UIApplication.
My problem was, that the screen kept turning dark as soon as I switched music tracks on the iPod player via the headphone remote. My guess is, that this is the same issue as you are experiencing.
You should simply turn off the idle timer. What I usually do in a viewcontroller that needs to stay 'awake' is this:
- (void) viewWillAppear:(BOOL)animated
{
[[UIApplication sharedApplication] setIdleTimerDisabled: YES];
}
- (void) viewWillDisappear: (BOOL) animated
{
[[UIApplication sharedApplication] setIdleTimerDisabled: NO];
}
This will make sure the screen will not get locked due to user inactivity.
I found a solution to this problem. Invoke a method that disables the idleTimer in about 5 seconds after you start playing the music. It's a bit of a hack, but it is a workaround.
[[SoundEngine mainEngine] playMusic];
[self performSelector:#selector(setIdleTimeDisabled) withObject:nil afterDelay:5.0];
- (void) setIdleTimeDisabled {
[UIApplication sharedApplication].idleTimerDisabled = YES;
NSLog(#"Setting idleTimer to TRUE");}
let player = MPMusicPlayerController.applicationMusicPlayer()
player.setQueueWithStoreIDs(["some id"])
player.play()
player.pause()
Related
In my app I'm downloading lots of images on a method.
I'm using a
downloadTask = [[UIApplication sharedApplication]
beginBackgroundTaskWithExpirationHandler:^{
[[UIApplication sharedApplication] endBackgroundTask:downloadTask];
downloadTask = UIBackgroundTaskInvalid;
}];
This is working fine, if I press the home or sleep button, the images continue downloading.
I'm showing the progress in a UIProgressView inside an UIAlertView, and when the percent is 100% the alertView is dissmised and I change the viewController to other where I show the donwloaded images.
But I only want this to happen if the app is really active at the moment the download finish.
I have been looking at the app state and while it's downloading with the screen off.
[UIApplication sharedApplication].applicationState
the state is UIApplicationStateActive during all the donwload
How can I can know if the downloading is happening with the screen off or on?
EDITED AFTER ACCEPTING THE ANSWER:
I just discovered, if I tap the home button, the app enters in UIApplicationStateBackground, if I tap the wake/sleep it enters in UIApplicationStateInactive
Following the approach of the correct answer, my app contines donwloading in both cases.
The screen is off in two states (apart from when the app has not been even opened):
suspended : in this case you don't have to worry because the download won't procede until the app gets active again; It will enter this state on
background : it's in this state for a limited amount of time before going in suspend, and the screen is already off in this moment. Here you may want to check then whether to do all the things you said or not, because in this state code can be still executed. In this state the app status is UIApplicationStateBackground, so you could just perform a check like this:
You probably want to check whether the app is in background execution in order to achieve the result. Just like this:
if([[UIApplication sharedApplication] applicationState] != UIApplicationStateBackground) {
// Do stuff
}
If it's in background, so the screen is off.
UPDATE: after few test, what I figured out is that the behaviour you are expieriencing is probably due to the execution of the download on the main thread.
You should send the download on (for instance) the global queue. This way the application will enter the background state as expected:
....
[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
[[UIApplication sharedApplication] endBackgroundTask:self.bti];
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self doBackgroundStuff];
});
....
This way, if the app is put on background while the download is in progress, the application state will turn into UIApplicationStateBackground, and then you can check it as I wrote initially. If you are doing UI updates during the progress remember to send them back to the main thread (because the download is now on a different one).
You can check whether your app is running in the background or not by setting a flag in the designated application delegate methodsapplicationDidEnterBackground: and applicationWillEnterForeground:. Example:
- (void)applicationDidEnterBackground:(UIApplication *)application
_applicationRunsInForeground = NO;
}
- (void)applicationWillEnterForeground:(UIApplication *)application {
_applicationRunsInForeground = YES;
}
If you don't want to have this _applicationRunsInForeground flag inside your application delegate, you could observe the delegate's NSNotifications in your viewcontroller class instead (UIApplicationWillEnterForegroundNotification and UIApplicationDidEnterBackgroundNotification).
I've noticed that when my iPhone app enters the foreground after being suspended on an iPad2 (iOS version 4.3.3), the iPhone screen seems to shift up by a small amount after a split second. My understanding is that iOS takes a snapshot of the screen before suspending the app so it can quickly bring it back up when resuming, but it's not clear to me why it would be shifted. The status bar placeholder and iPhone image don't shift up, only the rest of the iPhone screen does. I don't see this problem in the 5.0 simulator.
Any ideas what's going on or how to fix this? Thanks
When the app loads, it displays the default.png file that you have in your app bundle. If you have this image the same as whatever the first screen of your app is (which apple suggests that you should do) then it is displaying this image, and then the actual screen once the app is done initializing. You can edit the png file by shifting up a pixel or two (you'll just have to guess and check to see exactly what you need).
The other possibility is that your default.png isnt the right size, so it is being resized when the app actually starts. Check that the dimensions are correct for the device you are testing on.
Setting the status bat to initially hidden caused this for me.
Status bar is initially hidden YES
This fixed it
- (void) setStatusBarVisible: (NSTimer *)timer
{
[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationNone];
}
- (void)applicationWillEnterForeground:(UIApplication *)application
{
[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];
[NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:#selector(setStatusBarVisible:) userInfo:nil repeats:NO];
}
It appears that setting then reseting (after a short delay) the status bar addresses this issue.
This fixes it but it shouldn't happen in the first place.
yes it happens when you come again to foreground. it happens with me & i have solved this issue by using
(void)layoutSubviews
that means i draws the things in layoutSubviews method which shifts & it works fine.
for more information on this check my problem & solution
So, I was looking for a way to keep the user's iPhone display on for a clock app. I found [UIApplication sharedApplication].idleTimerDisabled = YES; but that keeps the device from locking all of the time. I tried to [UIApplication sharedApplication].idleTimerDisabled = NO; when the application goes into the background, but that doesn't work. How can I safely keep the user's device from sleeping while my app is running?
Alter the idleTimerDisabled property whenever your app changes its active state - if you're going to be backgrounded, re-enable the timer, and when you regain control, disable the timer again.
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];
}
I'm currently attempting to set up background audio for an app I'm developing for iOS 4. The app doesn't have a dedicated music player viewController, however, unlike other background audio apps such as Pandora, which makes the task a bit more confusing.
I've set the appropriate Info.plist settings correctly and have an AVAudioPlayer object in my app delegate which is accessible from everywhere. When the user plays a song, I replace the AVAudioPlayer with a new one initialized with the song and play it. This all works great, except now I have no idea how to go about supporting remote control events.
Based on Apple's documentation, I have this:
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
[self becomeFirstResponder];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[[UIApplication sharedApplication] endReceivingRemoteControlEvents];
[self resignFirstResponder];
}
- (BOOL)canBecomeFirstResponder {
return YES;
}
- (void)remoteControlReceivedWithEvent:(UIEvent *)event {
switch(event.subtype) {
case UIEventSubtypeRemoteControlTogglePlayPause:
if([iPhoneAppDelegate backgroundAudioPlayer].playing)
[iPhoneAppDelegate pauseBackgroundAudioPlayer];
else
[iPhoneAppDelegate playBackgroundAudioPlayer];
break;
}
}
The thing is, where do I put this? Apple's documentation seems to suggest this should go in some view controller somewhere, but my app has lots of view controllers and navigation controllers. Wherever I try to put this, for some reason tapping the Toggle Play/Pause button in the multitasking tray remote controls either causes the song to just pause for a moment and then unpause, or somehow causes the song to play twice.
The documentation examples are a bit misleading, but there is no need to subclass anything anywhere. The correct place to put remoteControlReceivedWithEvent: is in the application delegate, as it remains in the responder chain regardless of whether the app is in the foreground or not. Also the begin/end receiving remote control events should be based on whether you actually need the events, not on the visibility of some random view.
I found a couple of solutions to receiving global remote control events on the Apple Developer Forums after a bit of searching.
One way is to subclass UIWindow and override its remoteControlReceivedWithEvent:.
The second, perhaps nicer way is to subclass UIApplication and override sendEvent:. That way, you can intercept all the remote control events and handle them there globally, and not have any other responders handle them later in the responder chain.
- (void)sendEvent:(UIEvent *)event {
if (event.type == UIEventTypeRemoteControl) {
// Handle event
}
else
[super sendEvent:event];
}
The second method didn't work for me, sendEvent was never called. However the first method worked just nicely (subclassing UIWindow).
I struggled with this one for a while and none of the answers above worked. The bug in my code, and I hope that it will help someone reading this, was that I had the AudioSession set to mix with others. You want to be the foreground audio player to get Remote Control events. Check to see if you have INCORRECT code like this:
[[AVAudioSession sharedInstance] setDelegate: self];
[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error: nil];
UInt32 doSetProperty = 0;
AudioSessionSetProperty (
kAudioSessionProperty_OverrideCategoryMixWithOthers,
sizeof (doSetProperty),
&doSetProperty
);
NSError *activationError = nil;
[[AVAudioSession sharedInstance] setActive: YES error: &activationError];
And remove the AudioSessionSetProperty, or change doSetProperty to 1.
No need to subclass Window or forward events. Simply handle it from your main view controller. See the Audio Mixer (MixerHost) example for details.
http://developer.apple.com/LIBRARY/IOS/#samplecode/MixerHost/Listings/Classes_MixerHostViewController_m.html
Documentation explains it very well.
https://developer.apple.com/library/ios/documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/Remote-ControlEvents/Remote-ControlEvents.html
One thing that seems to influence this behavior is any category options you set for your AVAudioSession using setCategory:withOptions:error: instead of just setCategory:error:. In particular, from trial and error, it appears that if you set AVAudioSessionCategoryOptionMixWithOthers you will not get remote control events; the now playing controls will still control the iPod app. If you set AVAudioSessionCategoryOptionDuckOthers you will get remote control events, but it seems like there may be some ambiguity regarding which app is controlled. Setting the categoryOptions to 0 or just calling setCategory:error: works best.
how to set iPhone device to stay active ( to not lock ) while my app is running ?
Any idea
I'm not sure if this prevents the device from locking, but you can prevent the screen from dimming with the UIApplication's idleTimerDisabled property:
[UIApplication sharedApplication].idleTimerDisabled = YES;
From the documentation:
Important: You should set this property only if necessary and should be sure to reset it to NO when the need no longer exists. Most applications should let the system turn off the screen when the idle timer elapses. This includes audio applications. With appropriate use of Audio Session Services, playback and recording proceed uninterrupted when the screen turns off. The only applications that should disable the idle timer are mapping applications, games, or similar programs with sporadic user interaction.
This code will prevent your iPhone from going to sleep while your app is running
// avoid sleeping when this application is running
UIApplication *application = [UIApplication sharedApplication];
application.idleTimerDisabled = YES;
// Or simpler
[[UIApplication sharedApplication] setIdleTimerDisabled: YES];
If you landed here looking for an answer in Swift, it's this:
UIApplication.sharedApplication().idleTimerDisabled = true
for Swift 3
UIApplication.shared.isIdleTimerDisabled = true
The warning in this comment still applies.