Detecting phone calls when the app is asleep - objective-c

Question

What i'm trying to do is an app that runs a code when a call is incoming. I know I cannot get any details of the caller and that is fine.
My issue so far is that it's only working when the app is in foreground.
This is my code:
#import <CoreTelephony/CoreTelephonyDefines.h>
#import <CoreTelephony/CTCallCenter.h>
#import <CoreTelephony/CTCall.h>
CTCallCenter *callCenter = [[CTCallCenter alloc] init];
[callCenter setCallEventHandler:^(CTCall *call) {
ONLog(#"Event handler called");
if ([call.callState isEqualToString: CTCallStateConnected]) {
ONLog(#"Connected");
} else if ([call.callState isEqualToString: CTCallStateDialing]) {
ONLog(#"Dialing");
} else if ([call.callState isEqualToString: CTCallStateDisconnected]) {
ONLog(#"Disconnected");
} else if ([call.callState isEqualToString: CTCallStateIncoming]) {
ONLog(#"Incomming");
}
}];
Can someone help me with making this run as a background task?
EDIT:
I used Richas' code like this:
__block UIBackgroundTaskIdentifier yourBackgroundTaskName;
yourBackgroundTaskName = [application beginBackgroundTaskWithExpirationHandler:^{
// CODE FOR EXPIRATION HANDLER BLOCK
[application endBackgroundTask: yourBackgroundTaskName];
yourBackgroundTaskName = UIBackgroundTaskInvalid;
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// DO YOUR STUFF HERE. START OF BACKGROUND TASK.
NSLog(#"Background time Remaining: %f",[[UIApplication sharedApplication] backgroundTimeRemaining]);
self.callCenter = [[CTCallCenter alloc] init];
[self.callCenter setCallEventHandler:^(CTCall *call) {
ONLog(#"Event handler called");
if ([call.callState isEqualToString: CTCallStateConnected]) {
ONLog(#"Connected");
} else if ([call.callState isEqualToString: CTCallStateDialing]) {
ONLog(#"Dialing");
} else if ([call.callState isEqualToString: CTCallStateDisconnected]) {
ONLog(#"Disconnected");
} else if ([call.callState isEqualToString: CTCallStateIncoming]) {
ONLog(#"Incomming");
}
}];
//WHEN YOU ARE DONE WITH YOUR TASK, TELL THAT TO SYSTEM
[application endBackgroundTask: yourBackgroundTaskName];
yourBackgroundTaskName = UIBackgroundTaskInvalid;
});
It only buys me 180 seconds of background running...
It's not working :) The call is not detected

Answer 1

You should check for following two methods for your problem:
- (UIBackgroundTaskIdentifier)beginBackgroundTaskWithName:(NSString *)taskName expirationHandler:(void (^)(void))handler`
- (UIBackgroundTaskIdentifier)beginBackgroundTaskWithExpirationHandler:(void (^)(void))handler
You can implement any of them in applicationDidEnterBackground & that can buy you some time (5-10 minutes). Code might be something like following:
- (void)applicationDidEnterBackground:(UIApplication *)application
{
UIBackgroundTaskIdentifier yourBackgroundTaskName;
yourBackgroundTaskName = [application beginBackgroundTaskWithExpirationHandler:^{
// CODE FOR EXPIRATION HANDLER BLOCK
[application endBackgroundTask: yourBackgroundTaskName];
yourBackgroundTaskName = UIBackgroundTaskInvalid;
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// DO YOUR STUFF HERE. START OF BACKGROUND TASK.
//WHEN YOU ARE DONE WITH YOUR TASK, TELL THAT TO SYSTEM
[application endBackgroundTask: yourBackgroundTaskName];
yourBackgroundTaskName = UIBackgroundTaskInvalid;
});
}
Hope, this should at least get you started.