#import <notify.h>
#define NotificationLock CFSTR("com.apple.springboard.lockcomplete")
#define NotificationChange CFSTR("com.apple.springboard.lockstate")
#define NotificationPwdUI CFSTR("com.apple.springboard.hasBlankedScreen")
static void screenLockStateChanged(CFNotificationCenterRef center,void* observer,CFStringRef name,const void*object,CFDictionaryRef userInfo)
{
  NSString* lockstate = (__bridge NSString*)name;
  if ([lockstate isEqualToString:(__bridge NSString*)NotificationLock]) {
    NSLog(@"locked.");
  } else {
    NSLog(@"lock state changed.");
  }
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  // Override point for customization after application launch.
  CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), NULL, screenLockStateChanged, NotificationLock, NULL, CFNotificationSuspensionBehaviorDeliverImmediately);
  CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), NULL, screenLockStateChanged, NotificationChange, NULL, CFNotificationSuspensionBehaviorDeliverImmediately);
  //setScreenStateCb();
  return YES;
}

static void setScreenStateCb()
{
　　
  uint64_t locked;
  __block int token = 0;
  notify_register_dispatch("com.apple.springboard.lockstate",&token,dispatch_get_main_queue(),^(int t){
  });
  notify_get_state(token, &locked);
  NSLog(@"%d",(int)locked);
}
- (void)applicationDidEnterBackground:(UIApplication *)application
{
  while (YES) {
    setScreenStateCb();
    sleep(1);
  }
}