iOS监听home，进入后台

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationWillResignActive:)
name:UIApplicationWillResignActiveNotification object:nil]; //监听是否触发home键挂起程序.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationDidBecomeActive:)
name:UIApplicationDidBecomeActiveNotification object:nil]; //监听是否重新进入程序程序.

- (void)applicationWillResignActive:(NSNotification *)notification

{
[_webView reload];
printf("按理说是触发home按下\n");
}

- (void)applicationDidBecomeActive:(NSNotification *)notification
{
printf("按理说是重新进来后响应\n");
}