请问iOS 开发怎么设置和获取锁屏的时间长短 ？

获取的时间 ， 我是不知道！可以监听锁屏， 程序在前台，这种比较简单。直接使用Darwin层的通知就可以了：

#import

#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;
}