How can I detect screen lock/unlock events on the iPhone?
Solution 1
Check this out, I wanted to detect the lock/unlock events, I solved it by Darwin notifications.
You can detect the event when the device is locked by "com.apple.springboard.lockcomplete"
.
//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
NSString *lockState = (NSString*)name;
NSLog(@"Darwin notification NAME = %@",name);
if([lockState isEqualToString:@"com.apple.springboard.lockcomplete"])
{
NSLog(@"DEVICE LOCKED");
}
else
{
NSLog(@"LOCK STATUS CHANGED");
}
}
-(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);
}
Solution 2
To detect lock/unlock inside app in swift 5 only this worked for me:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(applicationDidBecomeActive), name: UIApplication.willEnterForegroundNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(applicationDidEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil)
}
@objc func applicationDidBecomeActive(notification: NSNotification) {
print("ACTIVE")
}
@objc func applicationDidEnterBackground(notification: NSNotification) {
print("BACKGROUND")
}
Solution 3
You can't use
com.apple.springboard.lockcomplete
orcom.apple.springboard.lockstate
when submitting your app to App Store, your app will be rejected because it's private API.The
com.apple.springboard.lockcomplete
notification NOT always comes after thecom.apple.springboard.lockstate
notification, it may happen early or later. You need to set a timer to wait for that event.
So here is how you can detect screen lock and unlock status, in Swift 5:
struct NotificationName {
// Listen to CFNotification, and convert to Notification
public static let lockComplete = Notification.Name("NotificationName.lockComplete")
public static let lockState = Notification.Name("NotificationName.lockState")
// Handle lockComplete and lockState Notification to post locked or unlocked notification.
public static let locked = Notification.Name("NotificationName.locked")
public static let unlocked = Notification.Name("NotificationName.unlocked")
}
func addNotificationObservers() {
let lockCompleteString = "com.apple.springboard.lockcomplete"
let lockString = "com.apple.springboard.lockstate"
// Listen to CFNotification, post Notification accordingly.
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(),
nil,
{ (_, _, _, _, _) in
NotificationCenter.default.post(name: NotificationName.lockComplete, object: nil)
},
lockCompleteString as CFString,
nil,
CFNotificationSuspensionBehavior.deliverImmediately)
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(),
nil,
{ (_, _, _, _, _) in
NotificationCenter.default.post(name: NotificationName.lockState, object: nil)
},
lockString as CFString,
nil,
CFNotificationSuspensionBehavior.deliverImmediately)
// Listen to Notification and handle.
NotificationCenter.default.addObserver(self,
selector: #selector(onLockComplete),
name: NotificationName.lockComplete,
object: nil)
NotificationCenter.default.addObserver(self,
selector: #selector(onLockState),
name: NotificationName.lockState,
object: nil)
}
// nil means don't know; ture or false means we did or did not received such notification.
var receiveLockStateNotification: Bool? = nil
// when we received lockState notification, use timer to wait 0.3s for the lockComplete notification.
var waitForLockCompleteNotificationTimer: Timer? = nil
var receiveLockCompleteNotification: Bool? = nil
// When we received lockComplete notification, invalidate timer and refresh lock status.
@objc
func onLockComplete() {
if let timer = waitForLockCompleteNotificationTimer {
timer.invalidate()
waitForLockCompleteNotificationTimer = nil
}
receiveLockCompleteNotification = true
changeIsLockedIfNeeded()
}
// When we received lockState notification, refresh lock status.
@objc
func onLockState() {
receiveLockStateNotification = true
changeIsLockedIfNeeded()
}
func changeIsLockedIfNeeded() {
guard let state = receiveLockStateNotification, state else {
// If we don't receive lockState notification, return.
return
}
guard let complete = receiveLockCompleteNotification else {
// If we don't receive lockComplete notification, wait 0.3s.
// If nothing happens in 0.3s, then make sure we don't receive lockComplete, and refresh lock status.
waitForLockCompleteNotificationTimer = Timer.scheduledTimer(withTimeInterval: 0.3, repeats: false, block: { _ in
self.receiveLockCompleteNotification = false
self.changeIsLockedIfNeeded()
})
return
}
// When we determined lockState and lockComplete notification is received or not.
// We can update the device lock status by 'complete' value.
NotificationCenter.default.post(
name: complete ? NotificationName.locked : NotificationName.unlocked,
object: nil
)
// Reset status.
receiveLockStateNotification = nil
receiveLockCompleteNotification = nil
}
Solution 4
May be you need to implement following methods in AppDelegate
:
Tells the delegate that the application is now in the background.
- (void)applicationDidEnterBackground:(UIApplication *)application
Tells the delegate that the application has become active.
- (void)applicationDidBecomeActive:(UIApplication *)application
Tells the delegate that the application is about to become inactive.
- (void)applicationWillResignActive:(UIApplication *)application
Solution 5
Actually I want the if I exit the application and lock the iPhone , and after some time I have unlock the iPhone , then exit Applications show the notifications or Alert the Start-up the Applications.
You can't do that on the iPhone.
![Vikas S Singh](https://i.stack.imgur.com/j80UU.png?s=256&g=1)
Vikas S Singh
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Updated on July 09, 2022Comments
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Vikas S Singh almost 2 years
How can I detect screen lock/unlock events on the iPhone? When the user unlocks it, I want to show a notification alert from my iPhone app. (For Just like Broadcast Receiver for screen unlock in Android.)
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Vikas S Singh over 12 years@ Nekto Actually i want the if i exit the application and lock the iPhone , and after some time i have unlock the iPhone , then exit Applications show the notifications or Alert the Start-up the Applications. For Example just like Window in Start-up options , skype , gtalk etc.
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Nekto over 12 yearsI don't understand what you want. May be it is not possible.
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Vikas S Singh over 12 years@ Nekto i want to simply say That: how can i make my application start on the iPhone start up ?
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Nate over 11 yearsI realize that you are trying to respond to a comment the poster made below, but answers should be answers to the question posed above, and as such, this answer is not really correct. If you have a response to a comment, it should be made as another comment where the original one was made.
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Oliver over 11 years@Nate : You're right, this seems to be a post on my beginnings when I didn't perfectly masterize the way SO was working.
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Nate over 11 yearsNo problem. You can delete an old answer if you like, and simply move the content ("You can't do that on the iPhone") to the comment section where it is best located. Of course, it looks like Nekto also made the same comment, so maybe just upvoting his comment is enough :)
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Victor Ronin over 11 yearsActually this code could be problematic in this case. com.apple.springboard.lockstate" will come both when on lock and unlock. So, if you try to do some action only on unlock, this code will require some additional logic. As example tracking your current status (whether device is locked or not). If device is locked and you got "com.apple.springboard.lockstate" then it's real unlock event else it's just prelude to com.apple.springboard.lockcomplete
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Rohit Kashyap over 11 yearsNow you can track the state completely: int result = notify_get_state(notifyToken, &state); See the link : stackoverflow.com/questions/14352228/…
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Victor Ronin over 11 yearsPlease take a look on the pitfalls of notify_get_state method, which I wrote and Nate answered here (stackoverflow.com/questions/14820249/…).
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Prince Kumar Sharma about 11 yearsgood one , but it works reverse.DEVICE LOCKED call on unlock screen and I want that so get +1 by me.
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Sauvik Dolui over 8 yearsThanks for that solution. I want little bit more help. I want to develop an app to trace phone usages by listening every screen lock/unlock events on iOS devices. I am perfectly receiving those notifications while app is in foreground but for background mode or when the app is not running at all, I fail to listening those notifications. Is there a way that I an listen to them even when the app is not running or the app is in background?
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esttorhe over 8 yearsThis is not wha the OP asked. They asked about detecting locks/unlocks of the iPhone and your solution only fires when the app goes to background, there are multiple reasons an app can go to background, user hit home button, user tapped a notification that took them to another app, user answered a call, etc.
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Nate over 7 yearsActually, the comment in the code is not correct.
lockcomplete
may actually come beforelockstate
. I'm observing that right now on iOS 9.3. Best not to rely on order here. -
Carl G over 7 yearsI don't think this answer is correct. There are several apps on my phone that seem to show a notification exactly after I unlock my phone. (Foursquare, I'm looking at you.)
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Dae KIM about 7 yearsThis solution seems no longer available. forums.developer.apple.com/message/224401#224401
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Praxiteles about 7 years@SauvikDolui Sauvik - were you able to solve the ability to track phone use by tracking locking and unlocking?
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Gauri Shankar about 4 yearsUIApplication.shared.isIdleTimerDisabled = true