#import <CoreTelephony/CTTelephonyNetworkInfo.h>

string GetNetWorkType(){    string strNetworkType = "";

    //创建零地址，0.0.0.0的地址表示查询本机的网络连接状态    struct sockaddr_storage zeroAddress;

    bzero(&zeroAddress, sizeof(zeroAddress));    zeroAddress.ss_len = sizeof(zeroAddress);    zeroAddress.ss_family = AF_INET;

    // Recover reachability flags    SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);    SCNetworkReachabilityFlags flags;

    //获得连接的标志    BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);    CFRelease(defaultRouteReachability);

    //如果不能获取连接标志，则不能连接网络，直接返回    if (!didRetrieveFlags)    {        return strNetworkType;    }

    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        strNetworkType = "WIFI";    }

    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            strNetworkType = "WIFI";        }    }

    if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)    {        if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0)        {            CTTelephonyNetworkInfo * info = [[CTTelephonyNetworkInfo alloc] init];            NSString *currentRadioAccessTechnology = info.currentRadioAccessTechnology;

            if (currentRadioAccessTechnology)            {                if ([currentRadioAccessTechnology isEqualToString:CTRadioAccessTechnologyLTE])                {                    strNetworkType =  "4G";                }                else if ([currentRadioAccessTechnology isEqualToString:CTRadioAccessTechnologyEdge] || [currentRadioAccessTechnology isEqualToString:CTRadioAccessTechnologyGPRS])                {                    strNetworkType =  "2G";                }                else                {                    strNetworkType =  "3G";                }            }        }        else        {            if((flags & kSCNetworkReachabilityFlagsReachable) == kSCNetworkReachabilityFlagsReachable)            {                if ((flags & kSCNetworkReachabilityFlagsTransientConnection) == kSCNetworkReachabilityFlagsTransientConnection)                {                    if((flags & kSCNetworkReachabilityFlagsConnectionRequired) == kSCNetworkReachabilityFlagsConnectionRequired)                    {                        strNetworkType = "2G";                    }                    else                    {                        strNetworkType = "3G";                    }                }            }        }    }

    if (strNetworkType == "") {        strNetworkType = "WWAN";    }

    NSLog( @"GetNetWorkType() strNetworkType :  %s", strNetworkType.c_str());

    return strNetworkType;}