判断设备有没有连接信号（WiFi,2G,3G等）

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;

        }

    }

    int netType = NETWORK_TYPE_NONE;

    NSNumber * num = [dataNetworkItemView valueForKey:@"dataNetworkType"];