I have used GPS location updates in my application. I want to detect if the iOS device is in sleep mode so that I can turn off the GPS location updates and optimize the battery use. I have already tried pausesLocationupdates in iOS 6, but it does not work as desired. I want to turn off the GPS location updates as soon as the device goes to sleep mode. I want to detect the lock/unlock event in the device.
Is there any way to achieve this functionality ?
so far I got the darwin notifications as given below
-(void)registerForall
{
//Screen lock notifications
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.iokit.hid.displayStatus"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.springboard.lockstate"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.springboard.hasBlankedScreen"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.springboard.lockcomplete"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
}
//call back
static void displayStatusChanged(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo)
{
NSLog(@"IN Display status changed");
NSLog(@"Darwin notification NAME = %@",name);
}
I am able to get the darwin notifications when device is locked/unlocked, but the real problem is how identify between if the notification has come from locking or the unlocking of the device. Console logs are:
LockDetectDemo[2086] <Warning>: IN Display status changed
LockDetectDemo[2086] <Warning>: Darwin notification NAME = com.apple.springboard.lockcomplete
LockDetectDemo[2086] <Warning>: IN Display status changed
LockDetectDemo[2086] <Warning>: Darwin notification NAME = com.apple.springboard.lockstate
LockDetectDemo[2086] <Warning>: IN Display status changed
LockDetectDemo[2086] <Warning>: Darwin notification NAME = com.apple.springboard.hasBlankedScreen
LockDetectDemo[2086] <Warning>: IN Display status changed
LockDetectDemo[2086] <Warning>: Darwin notification NAME = com.apple.iokit.hid.displayStatus
Any private API would also suffice. Thanks in advance.
I solved it like this:
//call back
static void displayStatusChanged(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo)
{
// the "com.apple.springboard.lockcomplete" notification will always come after the "com.apple.springboard.lockstate" notification
CFStringRef nameCFString = (CFStringRef)name;
NSString *lockState = (NSString*)nameCFString;
NSLog(@"Darwin notification NAME = %@",name);
if([lockState isEqualToString:@"com.apple.springboard.lockcomplete"])
{
NSLog(@"DEVICE LOCKED");
//Logic to disable the GPS
}
else
{
NSLog(@"LOCK STATUS CHANGED");
//Logic to enable the GPS
}
}
-(void)registerforDeviceLockNotif
{
//Screen lock notifications
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.springboard.lockcomplete"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.springboard.lockstate"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
}
Note: the "com.apple.springboard.lockcomplete" notification will always come after the "com.apple.springboard.lockstate" notification
The order of the two notifications can no longer be relied upon, as of recent versions of iOS