//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;}//在需要用的地方实现以下2个方法//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]) {       Reachability ＊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";        }}

typedef enum {    NETWORK_TYPE_NONE = 0,    NETWORK_TYPE_2G   = 1,    NETWORK_TYPE_3G   = 2,    NETWORK_TYPE_4G   = 3,    NETWORK_TYPE_5G   = 4,//  5G目前为猜测结果    NETWORK_TYPE_WIFI = 5}NETWORK_TYPE;-(NSString *)getNetworkType{    NSString *connectionKind;    if ([self isConnectToNewtwork]) {        UIApplication *app = [UIApplication sharedApplication];        NSArray *subviews = [[[app valueForKey:@"statusBar"] valueForKey:@"foregroundView"] subviews];        NSNumber *dataNetworkItemView = nil;        for (id subview in subviews) {            if([subview isKindOfClass:[NSClassFromString(@"UIStatusBarDataNetworkItemView") class]])     {                dataNetworkItemView = subview;                break;            }        }        NETWORK_TYPE nettype = NETWORK_TYPE_NONE;        NSNumber * num = [dataNetworkItemView valueForKey:@"dataNetworkType"];        nettype = [num intValue];               switch ( nettype ) {            case NETWORK_TYPE_NONE:                connectionKind = @"没有网络链接";                break;            case NETWORK_TYPE_WIFI:                connectionKind = @"当前使用的网络类型是WIFI";                break;            case NETWORK_TYPE_4G:                connectionKind = @"当前使用的网络链接类型是WWAN（4G）";                break;            case NETWORK_TYPE_3G:                connectionKind = @"当前使用的网络链接类型是WWAN（3G）";                break;            case NETWORK_TYPE_2G:                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"；           }    return connectionKind;}