Some days ago I posted a question about NSThread. Finally I managed to make it run in background every minute.
The aim of the app is to get the location and then call to a webservice to update it on a server with ASIHTTPRequest every X minutes.
The code:
- (void)threadEntryPoint:(ActualizarPosicionGPS2AppDelegate *)paramSender{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
while([[NSThread currentThread] isCancelled] == NO){
[NSThread sleepForTimeInterval:60.0f];
if ([[NSThread currentThread] isCancelled] == NO &&
[[UIApplication sharedApplication] backgroundTimeRemaining] != DBL_MAX) {
[self hacerCosasBackground];
}
}
[pool release];
}
hacerCosasBackground calls to the locationManager updating it's position and then uploads the position to a server.
In application:didFinishLaunchingWithOptions:
[NSThread detachNewThreadSelector:#selector(threadEntryPoint:) toTarget:self withObject:self];
-(void) endTaskWidthIdentifier:(NSNumber *)paramIdentifier{
UIBackgroundTaskIdentifier identifier = [paramIdentifier integerValue];
[[UIApplication sharedApplication] endBackgroundTask:identifier];
}
- (void)applicationDidEnterBackground:(UIApplication *)application {
self.backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^{
NSNumber *backgroundTask = [NSNumber numberWithInteger:self.backgroundTaskIdentifier];
[self performSelectorOnMainThread:#selector(endTaskWidthIdentifier:) withObject:backgroundTask waitUntilDone:YES];
self.backgroundTaskIdentifier = UIBackgroundTaskInvalid;
}];
}
However, the NSThread dies about 10 minutes later of closing the app. I've registered in the info.plist the 'UIBackgroundModes' location.
I also read about startMonitoringSignificantLocationChanges but I want to make my app very configurable (the user will be able to set the how often they want to update the location, etc.) and I understood that that method updates every 500m (that's not good, I want to update the location more often).
What could I do? Any help please?
Thank you very much!
Related
I've read so many question here at stackoverflow and I am still having issues with CLLocationManager.I have already added keys in info.plist (NSLocationAlwaysAndWhenInUseUsageDescription,NSLocationWhenInUseUsageDescription,NSLocationAlwaysAndWhenInUseUsageDescription). My app supports ios 9.0 to 11.x.
Update:- I'm testing on iphone6 ios 11.0.3 physical device
My Approach -
1. Start updating location after while using the app permission.
2. When app goes into background stop location manager to remove Blue Banner (Banner Of Shame)
3.Fire a periodic timer of 30 seconds and start location manager again.
This time I never got the delegate callback didUpdateLocation
I have a singleton class called LocationManager.
Here is my code from LocationManager and AppDelegate
LocationManager
- (void)startLocatingUser {
//Locate User
_locationMeasurements = [NSMutableArray array];
self.geocoder = [[CLGeocoder alloc] init];
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
self.locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
self.locationManager.distanceFilter = kCLDistanceFilterNone;
self.locationManager.pausesLocationUpdatesAutomatically = NO;
self.locationManager.activityType = CLActivityTypeAutomotiveNavigation;
if ([self.locationManager respondsToSelector:#selector(setAllowsBackgroundLocationUpdates:)]) {
[self.locationManager setAllowsBackgroundLocationUpdates:YES];
}
if(IS_OS_8_OR_LATER) {
if ([self.locationManager respondsToSelector:#selector(requestAlwaysAuthorization)]) {
[self.locationManager requestAlwaysAuthorization];
}
}
if (#available(iOS 11.0, *)) {
self.locationManager.showsBackgroundLocationIndicator = NO;
}
[self.locationManager startUpdatingLocation];
}
- (void)stopLocatingUser {
if(self.locationManager) {
[self.locationManager stopUpdatingLocation];
}
}
AppDelegateCode
- (void)applicationWillResignActive:(UIApplication *)application {
_isBackgroundMode = YES;
}
- (void)applicationDidEnterBackground:(UIApplication *)application {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
LocationManager* locationManager = [LocationManager sharedLocationManager];
[locationManager stopLocatingUser];
__block UIBackgroundTaskIdentifier bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
[application endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
self.bgTimer = [NSTimer scheduledTimerWithTimeInterval:30.0
target:self
selector:#selector(startTrackingBg)
userInfo:nil
repeats:YES];
}
-(void)startTrackingBg {
dispatch_async(dispatch_get_main_queue(), ^{
LocationManager* locationManager = [LocationManager sharedLocationManager];
[locationManager startLocatingUser];
});
NSLog(#"App is running in background");
}
I am never getting this delegate callback in background once I stop and start location manager again.
- (void)locationManager:(CLLocationManager *)manager
didUpdateLocations:(NSArray *)locations
What I simply want is whenever user puts the app in background. I want to hide the banner of shame and then I need periodic location updates in background and send them to server.
I have a settings panel in my app. Whenever the user presses a button, the object is updated on another thread as the UI updates. I have a separate label on the main view that is supposed to update the object count when the object has finished updating (which I want to happen regardless of whether the settings panel is up or down). I've tried following the apple documentation regarding this very topic, but it doesn't seem to work out for me - that is, it seems that the main view controller never receives the notification for some reason. Does anyone have any suggestions on how to alert the main view controller that an object passed to another thread has finished updating? Here's the code I'm using (most of which was copied from that doc):
Object Class:
[[NSNotificationCenter defaultCenter] postNotificationName: #"ScaleCountUpdated" object: self];
Main View Controller
- (void)setUpThreadingSupport
{
if (self.notifications) {
return;
}
self.notifications = [[NSMutableArray alloc] init];
self.notificationLock = [[NSLock alloc] init];
self.notificationThread = [NSThread currentThread];
self.notificationPort = [[NSMachPort alloc] init];
[self.notificationPort setDelegate: self];
[[NSRunLoop currentRunLoop] addPort: self.notificationPort
forMode: (NSString *)kCFRunLoopCommonModes];
}
- (void)handleMachMessage:(void *)msg
{
[self.notificationLock lock];
while ([self.notifications count]) {
NSNotification *notification = [self.notifications objectAtIndex: 0];
[self.notifications removeObjectAtIndex: 0];
[self.notificationLock unlock];
[self processNotification: notification];
[self.notificationLock lock];
};
[self.notificationLock unlock];
}
- (void)processNotification:(NSNotification *)notification{
if ([NSThread currentThread] != self.notificationThread) {
// Forward the notification to the correct thread.
[self.notificationLock lock];
[self.notifications addObject: notification];
[self.notificationLock unlock];
[self.notificationPort sendBeforeDate: [NSDate date]
components: nil
from: nil
reserved: 0];
} else {
[self updateScaleCount];
}
}
- (void)updateScaleCount
{
NSLog(#"[ScalesViewController - updateScaleCount]: Scales updated from notification center.");
if([UserDefinedScales areScalesGrouped] == YES){
self.groupCountLabel.text = [NSString stringWithFormat: #"Group Count: %i", [[UserDefinedScales sortedKeys] count]];
} else {
self.groupCountLabel.text = #"Group Count: 1";
}
self.scaleCountLabel.text = [NSString stringWithFormat: #"Scale Count: %i", [UserDefinedScales scaleCount]];
}
Main View Controller - View Did Load:
[self setUpThreadingSupport];
[[NSNotificationCenter defaultCenter] addObserver: self
selector: #selector(processNotification:)
name: #"ScaleCountUpdated"
object: nil];
If you have any suggestions on how to alter this code to make it function correctly, or have another solution to offer for achieving this, it would be greatly appreciated! Thank you.
It looks to me like you are doing it correctly, i.e. register for notification and send it.
As far as I can see from your code and the information you give, you can basically completely forget about the setupThreadingSupport. You should definitely test it without it. Not sure what you want to achieve, but looks like overkill where probably a simple block would suffice. Is there a compelling reason to listen to the notification on a background thread? Why not let the notification center decide?
Log the sending and receiving of the notifications - addObserver and postNotification is really all this mechanism needs to work as expected.
I would go to a simpler implementation. The NSNotificationCenter already provides all the mechanisms you need to broadcast and receive messages across your app.
If you fire the notification from a background thread you can use a GCD dispatch_async to make make it delivered on the main thread.
Object Class
dispatch_async(dispatch_get_main_queue(), ^{
// You don't need to pass the object itself here as you are not using it later.
[[NSNotificationCenter defaultCenter] postNotificationName:#"ScaleCountUpdated"];
}
MainViewController
-(void)viewDidLoad
{
[super viewDidLoad];
// Register your controller as an observer for a specific message name
[[NSNotificationCenter defaultCenter] addObserver: self
selector: #selector(updateScaleCount)
name: #"ScaleCountUpdated"
object: nil];
}
- (void)updateScaleCount
{
NSLog(#"[ScalesViewController - updateScaleCount]: Scales updated from notification center.");
if([UserDefinedScales areScalesGrouped] == YES){
self.groupCountLabel.text = [NSString stringWithFormat: #"Group Count: %i", [[UserDefinedScales sortedKeys] count]];
} else {
self.groupCountLabel.text = #"Group Count: 1";
}
self.scaleCountLabel.text = [NSString stringWithFormat: #"Scale Count: %i", [UserDefinedScales scaleCount]];
}
I face an issue where my app requires the users location when they receive a push notification while the app is running in the background.
After doing a bit of reading I'm under the impression that this isn't possible, i.e:
1) App in background
2) Push notification received
3) Get users location and execute block of code.
I found this post on here that suggests you can run a task every N amount of minutes to get the users location. So using this I could check say every ten minutes which would work but it would be a waste of the users battery if I kept activating the GPS. Therefore I was wondering can I tell within my background task if the user has any push notification waiting for my app? That way I would check if they did every ten minutes and only activate the GPS if they did.
Perhaps I'm going about this all the wrong way, I would really appreciate any advice. Sorry for not having any of the code for the background task yet as I'm still trying to get it to work.
[UPDATE]
Thanks Dustin for your advice. After a bit of testing I've decided to go with an easier option. I am now using the Apple Significant Location Changes. I store the changes in an array, I've set this to only update if the last change was greater than 10min ago. Then when the app becomes active I match the closest time in the array to the time the push notification was sent and use that location.
As discussed I used alternative solution, here it is:
Under viewDidLoad or didFinishingLaunchingWithOptions add:
locationsLogged = [[NSMutableArray alloc] init];
lastLocationTime = [[NSDate alloc] init]
locationManager = [[CLLocationManager alloc] init];
[locationManager setDelegate:self];
[locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
Under applicationDidEnterBackground add:
[locationManager startMonitoringSignificantLocationChanges];
Add:
-(void) storeLocations:(CLLocation *)location
{
bgTask = [[UIApplication sharedApplication]
beginBackgroundTaskWithExpirationHandler:
^{
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
}];
[locationsLogged addObject:location];
if (bgTask != UIBackgroundTaskInvalid)
{
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
}
-(void) locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
BOOL isInBackground = NO;
if ([UIApplication sharedApplication].applicationState == UIApplicationStateBackground)
{
isInBackground = YES;
}
NSDate *now = [NSDate date];
NSTimeInterval diff = [now timeIntervalSinceDate:lastLocationTime];
if ((int)diff > 600) {
if (isInBackground)
{
[lastLocationTime release];
lastLocationTime = [[NSDate alloc] init];
[self storeLocations:newLocation];
}
else
{
// ...
}
}
}
Then on applicationDidBecomeActive you can use whatever logic you need to apply location information.
I'm using an NSOperation to collect data that should be downloaded (takes 2-5 sec.) and afterwards I download this. I've put a ASINetworkQueue inside this NSOperation to start downloading the previously collected data.
Everything works fine but when I call cancelAllOperations on my ASINetworkQueue, the main thread blocks and the UI Freezes. Why is this happening? Everything else works fine.
Here is my Code:
- (void)main {
//ManagedObjectContext for operations
AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
self.managedObjectContext = [[NSManagedObjectContext alloc] init];
[self.managedObjectContext setPersistentStoreCoordinator: [appDelegate persistentStoreCoordinator]];
// Register context with the notification center
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self
selector:#selector(mergeChanges:)
name:NSManagedObjectContextDidSaveNotification
object:self.managedObjectContext];
[self startDownload];
if (!self.downloadDidFail) {
[self moveFiles];
[self.managedObjectContext save:nil];
}
}
- (void)startDownload {
self.downloadQueue = [ASINetworkQueue queue];
self.downloadQueue.delegate = self;
[self.downloadQueue setRequestDidFailSelector:#selector(dataRequestFailed:)];
[self.downloadQueue setRequestDidFinishSelector:#selector(dataRequestFinished:)];
[self.downloadQueue setQueueDidFinishSelector:#selector(dataQueueFinished:)];
[self.downloadQueue setShouldCancelAllRequestsOnFailure:YES];
[self.downloadQueue setDownloadProgressDelegate:self.progressView];
for (File *dataFile in self.dataFiles) {
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:dataFile.url]];
[request setDownloadDestinationPath:dataFile.path];
[self.downloadQueue addOperation:request];
}
}
[self.downloadQueue go];
[self.downloadQueue waitUntilAllOperationsAreFinished];
}
- (void)dataRequestFinished:(ASIHTTPRequest *)request {
NSLog(#"DL finished");
}
- (void)dataRequestFailed:(ASIHTTPRequest *)request {
DLog(#"Download failed");
self.downloadDidFail = YES;
}
- (void)dataQueueFinished:(ASINetworkQueue *)queue {
DLog(#"Finished Data Queue");
}
- (void)cancelDownload {
self.canceledDownload = YES;
[self.downloadQueue cancelAllOperations];
}
I had the same problem and solved by calling:
[queue setShouldCancelAllRequestsOnFailure:NO]
before calling:
[queue cancelAllOperations].
ASI requests responses and queue responses are deliberately moved to the main thread for library design purposes.
You have two solution:
-Subclass ASIHTTPRequest and overwrite 2 methods. (Look for in the code something like "subclass for main thread").
-Modify the library. (Easy, but personally I don't like this solution).
What does your failure delegate method do? ASIHTTPRequest will run that on the main thread by default, so if it does a lot of processing (or there are a lot of requests) this could take quite some time.
I'm trying to add a spinning activity indicator (UIActivityIndicatorView) to my app while it parses data from the internet. I have an IBOutlet (spinner) connected to a UIActivityIndicatorView in IB. Initially I had it set up like this:
-
(void) function {
self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle: UIActivityIndicatorViewStyleWhite];
self.spinner.hidesWhenStopped = YES;
[spinner startAnimating];
//parse data from internet
[spinner stopAnimating];}
But the spinner wouldn't spin. I read that it had something to do with everything being on the same thread. So I tried this:
- (void) newFunction {
self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle: UIActivityIndicatorViewStyleWhite];
self.spinner.hidesWhenStopped = YES;
[spinner startAnimating];
[NSThread detachNewThreadSelector: #selector(function) toTarget: self withObject: nil];
[spinner stopAnimating];}
But still no luck. Any ideas? Thanks.
Your newFunction: method should look like this:
- (void) newFunction {
self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
self.spinner.hidesWhenStopped = YES;
[NSThread detachNewThreadSelector: #selector(function) toTarget: self withObject: nil];
}
And your function method should look like this:
- (void) function {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
[self.spinner performSelectorOnMainThread:#selector(startAnimating) withObject:nil waitUntilDone:NO];
//...
[self.spinner performSelectorOnMainThread:#selector(stopAnimating) withObject:nil waitUntilDone:NO];
[pool drain];
}
you should not intitialize indicator again .please replace your code with this.
-(void) function {
[spinner startAnimating];
[self performSelector:#selector(newfunction) withObject:nil afterDelay:3.0];
}
- (void) newfunction {
[spinner stopAnimating];
}
Thanks.
Just see that the "//parse data from internet " is synchronous or asynchronous. Asynchronous would mean that a separate thread would start from that point on, and the current function execution will continue without delay.
In your second example, you are explicitly making separate thread, which means that #selector(function) will happen on a separate thread, and the next statement [spinner stopAnimating] is executed immediately. So, it seems like spinner is not spinning at all.
Moreover, make sure you start and stop the activity indicator on main thread only.