ios - 获取 iPhone 被锁定的时长

Question

如果我想在手机恢复时使用它来增加计时器进度 View ，或者安排在手机仍处于锁定状态时触发通知，我将如何获取手机被锁定的时间长度？

Answer 1

实现 UIApplicationDelegate 方法 applicationWillResignActive:和 applicationDidBecomeActive: 。

您必须在调用前者时存储当前时间，并在调用后者时计算差值。具体来说，在您的应用程序委托(delegate)中:

#define TIMESTAMP_KEY @"timestamp"

- (void)applicationWillResignActive:(UIApplication *)application
{
   NSInteger *timestamp = [[NSDate date] timeIntervalSince1970];
   [[NSUserDefault standardUserDefaults] setInteger:timestamp forKey:TIMESTAMP_KEY];
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
   NSInteger *newTimestamp = [[NSDate date] timeIntervalSince1970];
   NSInteger *oldTimestamp = [[NSUserDefault standardUserDefaults] integerForKey:TIMESTAMP_KEY];
   NSInteger *secondsPassed = newTimestamp - oldTimestamp;
   // Now you can resynch your timer with the secondsPassed 
}