两个方法：
1、查看屏幕的亮度
CGFloat screenBrightness = [[UIScreen mainScreen] brightness];if (screenBrightness > 0) {// todo}
2、监听com.apple.springboard.lockcomplet
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(),(void *)self,screenLockStatus,CFSTR("com.apple.springboard.lockcomplete"),NULL,CFNotificationSuspensionBehaviorDeliverImmediately);void screenLockStatus(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo){PlaybackControlPlayer * playbackControlPlayer= (__bridge PlaybackControlPlayer *)observer;NSString* lockState = (__bridge NSString*)name;if([lockState isEqualToString:@"com.apple.sprin
