iphone判断当前网络连接类型

//Reachability.m 中 networkStatusForFlags 方法重构
- (NetworkStatus) networkStatusForFlags: (SCNetworkReachabilityFlags) flags
{
	if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
	{
		return NotReachable;
	}
    
	BOOL retVal = NotReachable;
	
	if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)
	{
		// if target host is reachable and no connection is required
		//  then we'll assume (for now) that your on Wi-Fi
		retVal = ReachableViaWiFi;
	}
	
	
	if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0) ||
         (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))
	{
        // ... and the connection is on-demand (or on-traffic) if the
        //     calling application is using the CFSocketStream or higher APIs
        if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)
        {
            // ... and no [user] intervention is needed
            retVal = ReachableViaWiFi;
        }
    }
    
    if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
	{
        if((flags & kSCNetworkReachabilityFlagsReachable) == kSCNetworkReachabilityFlagsReachable) {
            if ((flags & kSCNetworkReachabilityFlagsTransientConnection) == kSCNetworkReachabilityFlagsTransientConnection) {
                retVal = ReachableVia3G;
                if((flags & kSCNetworkReachabilityFlagsConnectionRequired) == kSCNetworkReachabilityFlagsConnectionRequired) {
                    retVal = ReachableVia2G;
                }
            }
        }
	}
	return retVal;
}

//检查当前网络连接是否正常
-(BOOL)connectedToNetWork
{
	struct sockaddr_in zeroAddress;
	bzero(&zeroAddress, sizeof(zeroAddress));
	zeroAddress.sin_len = sizeof(zeroAddress);
	zeroAddress.sin_family = AF_INET;
	
	SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);
	SCNetworkReachabilityFlags flags;
	
	BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);
	CFRelease(defaultRouteReachability);
	
	if (!didRetrieveFlags) {
		printf("Error. Count not recover network reachability flags\n");
		return NO;
	}
	
	BOOL isReachable = flags & kSCNetworkFlagsReachable;
	BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
	return (isReachable && !needsConnection) ? YES : NO;
}

//检查网络连接类型
-(void)checkNetworktype:(id)sender{
    NSString *connectionKind;
    if ([self connectedToNetWork]) {
		hostReach = [Reachability reachabilityWithHostName:@"www.google.com"];
        switch ([hostReach currentReachabilityStatus]) {
            case NotReachable:
                connectionKind = @"没有网络链接";
                break;
            case ReachableViaWiFi:
                connectionKind = @"当前使用的网络类型是WIFI";
                break;
            case ReachableVia3G:
                connectionKind = @"当前使用的网络链接类型是WWAN（3G）";
                break;
            case ReachableVia2G:
                connectionKind = @"当前使用的网络链接类型是WWAN（2G）";
                break;    
            default:
                break;
        }
	}else {
		connectionKind = @"没有网络链接";
	}
}

转自： http://www.oschina.net/code/snippet_588197_11928