Reachability(判断网络是否连接)

/*
* 在应用委托的方法didFinishLaunchingWithOptions中添加
*/

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];
reachability = [[Reachability reachabilityWithHostName:@"www.baidu.com"] retain];
[reachability startNotifier];
........
return YES;

/**
*此函数通过判断联网方式，通知给用户
*/
- (void)reachabilityChanged:(NSNotification *)notification
{
      Reachability *curReachability = [notification object];
      NSParameterAssert([curReachability isKindOfClass:[Reachability class]]);
      NetworkStatus curStatus = [curReachability currentReachabilityStatus];
      if(curStatus == NotReachable) {
          [DOIN_Util logFax:@"连接失败"];
      }
}