10.9 CoreBluetooth RetrivePeriperals - objective-c

Im developing an app on OSX that uses CoreBluetooth. I have encountered a problem on OSX Mavericks that i cant seem to get around. (All of this works perfectly on OSX 10.8).
First lets go through the flow of the application
This flow is fairly established and has been used used successfully in iOS apps and works on 10.8. So on Mavericks, the first run completes successfully. It scans, finds and connects to the device correctly. It also saves out the UUID of the device to a .plist file along with other properties.
Upon relaunch of the app, it attempts to go down the left hand column of the flow which is where the problems seem to occur.
So the first issue i noticed was that my call to self.central retrievePeripherals: never calls my delegate callback of -(void)centralManager:(CBCentralManager *)central didRetrievePeripherals:(NSArray *)peripherals
. It simply never gets the callback on Mavericks.
My next thought was "oh they have a new API for fetching peripherals on Mavericks and the old one is deprecated, lets try that". So i added in my calls to NSArray *identifiers = [self.central retrievePeripheralsWithIdentifiers:#[uuid]]; and i get caught in a sempahore wait trap. Upon closer debugging of what was going on it turned out that sometimes my CBCentralManager gets into a state of CBCentralManagerStateUnknown and never updates the state to a newer one.
The next thing i tried was to fire up Activity Monitor and kill the blued process. Finally, my delegate callback for -(void)centralManagerDidUpdateState:(CBCentralManager *)central was called with the correct CBCentralManagerStatePoweredOn so i performed retrievePeripheralsWithIdentifiers again and received an empty array.
So all of these problems seem to be linked to blued in some way. Does anyone have more insight into this process to elude as to what is going on?
My main question is. Why does this work the first time through the app but not the second? Upon quitting the app after the initial scan and connection it seems i can no longer use the system bluetooth for anything without resetting blued (which even then doesn't retrieve peripherals). Is there some sort of shutdown sequence i need to do on the CBCentralManager to keep blued from going AWOL?
Any advice would be greatly apprecciated!

While this is obviously a very old thread, I stumbled upon the same issue today and decided to post a fix for posterity.
I was trying to hack together a simple app based on the HeartRateMonitor example provided by Apple. Unfortunately, it does not work on 10.9 if autoConnect is set to TRUE, what's worse, it brings blued down on its knees.
In 10.9, a call to the (deprecated) retrievePeripherals freezes blued without a chance to restore. CBCentralManager goes into CBCentralManagerStateUnknown, Bluetooth cannot be turned on/off using OS functions etc. The only solution that I found is to killall -9 blued.
However, the synchronous retrievePeripheralsWithIdentifiers worked well for me (on 10.9.4). Here's the relevant excerpt from the modified HeartRateMonitor code:
/* Retreive already known devices */
if(autoConnect)
{
NSArray *peripherals = [manager retrievePeripheralsWithIdentifiers:[NSArray arrayWithObject:(id)aPeripheral.identifier]];
NSLog(#"Retrieved peripheral: %lu - %#", [peripherals count], peripherals);
[self stopScan];
/* If there are any known devices, automatically connect to it.*/
if([peripherals count] >=1)
{
[indicatorButton setHidden:FALSE];
[progressIndicator setHidden:FALSE];
[progressIndicator startAnimation:self];
peripheral = [peripherals objectAtIndex:0];
[peripheral retain];
[connectButton setTitle:#"Cancel"];
[manager connectPeripheral:peripheral options:[NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:CBConnectPeripheralOptionNotifyOnDisconnectionKey]];
}
}

Related

NSUserDefaults synchronize fails when the application quits

I’m using Xcode 8 under OS X 10.11.6 but the problem persists with Xcode 7. I have a main application and it’s helper, they share a group container.
prefsFile = [[NSUserDefaults alloc] initWithSuiteName:kAppGroupName];
When I synchronize the NSUserDefaults during the session, all works fine but the helper needs to synchronize the preferences file when it receive the applicationShouldTerminate message : when the Mac shuts down or is restarted. It seems that synchronize in this case has no effect and is ignored. Not always but sometimes, randomly.
I always test the returned value of the method synchronize and this value is always YES. If NO, a message is sent to the log of the application.
Is there a way to solve the problem ?

nsmanageobjectcontext.save stopped working in iOS7

The project I inherited was built and launched in April 2013, and it worked perfectly for ios 5.1, ios 6.0 and ios 6.1.
However i just installed the app to an iphone that has ios7.0 and it didn't work. I looked at the code and I see that the app downloads some JSON data from the web, and then when it tries to run the following 3 lines of code, "nothing happens" after the 2nd line.
NSError error = nil;
BOOL isSuccessful =[self.tempMoc save:&error]; // where tempMoc is a NSManagedObjectContext
NSLog(#"errrrrrr ----- %# --- errrrrrr", error);
When I say nothing happens, I mean that the code execution stops on the 2nd line, and no code after that line gets fired. I tried putting a breakpoint on the second line, then stepping into the function, but nothing happens...xcode doesn't show me anything new afterwards. The app in my simulator also hangs.
I tried changing the deployment target of my project from ios6 to ios7. Again, this yielded no effects.
What should I do next?
ADDITIONAL NOTES
I've been reading other stack overflow answers and some people say the a hanging [NSManagedObjectContext save] might be a threading issue. I'm not sure how to confirm if my issue is a threading issue. I know that there's only ONE place that calls the [NSManagedObjectContext save], and that's the one place where things are hanging. I tried putting a
[self.tempMoc.persistentStoreCoordinator lock];
right after instantiating self.tempMoc, but that had no effect.
I figured out the issue.
It was indeed multiple threads manipulating the NSManagedObjectContext that caused hte save function to hang.
My solution was to rewrite the code to get rid of all the extra threads. I was left with only the main thread and this fixed the issue.

App crash - "DiskImageCache: Could not resolve the absolute path of the old directory."

I am working on an app, where I display the data entered by user in a PDF file. PDF File is also created dynamically.
All this is fine.
I have implemented QuickLook framework to display the pdf file. When I call the QL framework, PDF file id displayed quite fine but when come back to the calling screen, my app crashes without any crash log or memory warnings.
I am calling QL with below code:
[[self navigationController] presentModalViewController:qlPreviewer animated:YES];
logs created are
DiskImageCache: Could not resolve the absolute path of the old directory.
[Switching to process 3070 thread 0x17603]
[Switching to process 3070 thread 0x15503]
This is quite interesting.....
When I run the same program in Instruments to check for leaks and Memory Management, i can only find leaks when PDF document is scrolled and all the pages are viewed.
However, interestingly there is no app crash that I can see.
Also, I did try with ZombieEnabled = YES and without it but no app crash with Instruments.
I am quite clueless on how to interpret this and have been trying different things to solve this. Also, I have tried UIWebView but the result is the same.
I was again trying something to check out the issue and found something interesting.
When i execute the code directly from X-Code - i get the crash in as explained above.
In other instance, if I execute the app by clicking on the app in the sim... no crash
I am yet to check this on device. Can someone confirm the crash on the device?
Also, Google does not have answer to this question.
Thanks in advance for your answers.
Can anyone shed some light on this?
I'm having the exact same issue.
As a workaround, you can disable or remove your 'All Exceptions' breakpoint. This might make debugging a little more difficult, but it's not as bad as having to relaunch the application all the time.
This is the breakpoint causing the issue. I had set it so long ago that I'd forgotten it was there
Deleting application from device helped me to solve this problem.
Maybe also at first you should try "Product > Clean" to ensure that all resources will be copied to your device.
I was able to fix mine with this code:
FirstViewController.h
NSURLRequest* reqObj;
#property(nonatomic, retain) NSURLRequest* reqObj;
FirstViewController.m
reqObj = [NSURLRequest requestWithUrl:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:60.0];
NSURLConnection* conn = [[NSURLConnection alloc] initWithRequest:reqObj delegate:self];
then instead of loading it on my view after this line i waited for the connectionDidFinishLoading then load it to my view
Interesting: This has just started with my app too. No errors when checking for leaks but running the app in the sim actually is causing a Breakpoint, not a crash. I can hit the continue and the app keeps running, no problem.
My issue also is relating to a PDF, but I'm just using a web view to display a PDF from the app bundle. I've checked everything in the dealloc, it's all good, this may be a iOS 5.1 bug. I will update as I learn more.
#JimP, It isn't an iOS 5.1 bug. It has just started happening to my app as well, on iOS5.0. It seems to only affect pdfs of more than one page length, and seems to trigger most commonly on scrolling past the end of the document (although sometimes earlier also). It also seems to happen more often on a second load.
This could happen when you delete the object reference in code but having its reference in xib. Delete the outlet that you no longer need.
Just ran into this problem of loading a pdf file in an App I am converting to iOS 8. This App has been running fine since the first iPhone. I just removed the All Exceptions breakpoint to work around it.
I don't know if it's the same problem but I had an issue where switching from a PDF view to another more than three times via the tab bar controller caused a crash.
Turned out that embedding the views I was switching to within Navigation controllers put a stop to the crashing.

QTCaptureDevice Closing By itself (FaceTime Camera) Mac

I have a mac app that writes camera data to a file then uploads that file on an [NSTimer] to a server. However, after the camera runs for a while it closes itself and I see this in the log: * QTCaptureDeviceInput warning: The device "FaceTime HD Camera (Built-in)" was closed while still being used in a capture session. Make sure that the session is not running before closing any devices it is using.
No other apps are open that can use the camera in the test case and the object for the device is not being released by me. I have gone so far as to call retain on it to prevent this, to no avail.
I looked at Apple's docs and nowhere that I found did it talk about the camera being shut off by the system, so what could be causing this. In the meantime I have some code that periodically checks if it is open and if it isn't calls open on it.
One thing I forgot I am using this notification and it is being fired: QTCaptureDeviceWasDisconnectedNotification
Well, it took a while but I found the issue. When you you are pulling image data from a running QTCaptureDevice you need to work with individual frames via the following delegate method. If you fail to properly release the buffers on each run the camera will eventually close by itself. Please note the code below is CORRECt; I attached it to help anyone else reading this question. Hope this saves someone the time it costed me...
- (void) captureOutput:(QTCaptureOutput *)captureOutput didOutputVideoFrame:(CVImageBufferRef)videoFrame withSampleBuffer:(QTSampleBuffer *)sampleBuffer fromConnection:(QTCaptureConnection *)connection {
CVBufferRef bufferToBeReleased;
CVBufferRetain(videoFrame);
#synchronized (self) {
imageBufferToRelease = imageIWanted;
imageIWanted = videoFrame;
}
CVBufferRelease(bufferToBeReleased);
}

Objective-c -> class method to main file query

Sorry to bug twice so quickly, but since people were so kind in their informative responces, I figured it couldnt hurt to ask another question.
The same program i tried to make it rather swanky and have a main screen which allows you to click on a button which leads to a limited options screen. This lets you switch the music on or off. Or at least it should do.
The music running code is in the main file (game.m), under the following:
//Music
[Settings setMusicEnabled:YES];
music = [SPSound soundWithContentsOfFile:#"music.caf"];
channel = [[music createChannel] retain];
channel.loop = YES;
channel.volume = 0.25;
if([Settings musicEnabled]){
[channel play];
}
I apologize for the strange format, but it is Sparrow framework. basically, the Settings file contains the class methods I am trying to use. If the methods cause YES, the music is on. If it is No, then the music is off.
settings.m
static BOOL isMusicEnabled;
#implementation Settings
+ (BOOL)musicEnabled
{
return isMusicEnabled;
}
+ (void)setMusicEnabled:(BOOL)value
{
isMusicEnabled = value;
NSLog(#"SME? %i", isMusicEnabled);
}
#end
Now, the options file is working and i tested that section. The program is reading that isMusicEnabled is getting a new value, thus musicEnabled is being altered as well, so there should be a change and the music should be switched off.
However, nothing happens. I have tried to use debugger, but I am not very good at it and I dont understand a lot of the information i am given. I do understand that the problem is sending the message from Settings file to the main/Game file.
I would appriciate anyone's help who could enlighten me as to how this could be solved.
I'm not familiar with Sparrow Framework, but let me make a guess anyway.
[channel play]; starts playing the music in background until the channel is asked to stop playing.
Changing the isMusicEnabled does not trigger any code to stop the currently playing music. When you change the value in Settings, you should inform the channel to stop (most probably by somehow accessing the channel and calling [channel stop].
There's another problem - isMusicEnabled is just a variable in memory, your program will not remember its state between restarts. And Settings are usually supposed to be remembered.
To summarize I see two problems: persisting settings between restarts first and informing about change of settings second. To remember settings I suggest you look into NSUserDefaults class. To inform the channel to stop playing you have couple of options - depending on you skills. Easiest is to simply access the channel variable from within the setMusicEnabled and call stop. Another option would be to use notifications, but for a beginner programmer that is more complicated (look for NSNotificationCenter if interested).