正常情況下笋轨，在AppDelegate中實現(xiàn)下面兩個方法，能夠監(jiān)聽從后臺恢復到前臺
- (void)applicationDidEnterBackground:(UIApplication *)application
{
log4info(@"---applicationDidEnterBackground----");
//進入后臺
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
NSLog(@"---applicationDidBecomeActive----");
//進入前臺
}
但是單個UIViewController怎么監(jiān)聽呢
在-viewDidLoad方法中备典，添加一下代碼監(jiān)聽notification
[[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(someMethod:)
name:UIApplicationDidBecomeActiveNotification object:nil];
別忘了在-dealloc中將監(jiān)聽移除：
[[NSNotificationCenter defaultCenter] removeObserver:self];
