ios 监听app从后台恢复到前台

正常情况下，在AppDelegate中实现下面两个方法，能够监听从后台恢复到前台

- (void)applicationDidEnterBackground:(UIApplication *)application
{
log4info(@"---applicationDidEnterBackground----");
//进入后台
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{

NSLog(@"---applicationDidBecomeActive----");
//进入前台

}

但是单个UIViewController怎么监听呢

在-viewDidLoad方法中，添加一下代码监听notification

[[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(someMethod:)
name:UIApplicationDidBecomeActiveNotification object:nil];

别忘了在-dealloc中将监听移除：

[[NSNotificationCenter defaultCenter] removeObserver:self];

 

from : http://www.2cto.com/kf/201305/211374.html