@property (nonatomic, strong) Reachability *reacability;
ps:
注意事项：如果Reachability.m为MRC的，则初始化时，Reachability的对象一定要强引用，否则创建后会立刻释放掉，导致不能监听到。ARC时可以忽略。
self.reacability = [Reachability reachabilityWithHostName:@"www.baidu.com"];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationNetworkStatusChanged:) name:kReachabilityChangedNotification object:nil];
[self.reacability startNotifier];
- (void)applicationNetworkStatusChanged:(NSNotification *)noti {
switch (self.reacability.currentReachabilityStatus) {
case NotReachable:
{
}
break;
case ReachableViaWWAN:
{
}
break;
case ReachableViaWiFi:
{
}
break;
default:
{
}
break;
}
}
