昨天在判断网络的发现发现xcode12竟然没有5G相关的key，今天升级到Xcode12.1发现多了CTRadioAccessTechnologyNRNSA和CTRadioAccessTechnologyNR。

NR是New Radio的缩写，新无线(5G)的意思，
NRNSA表示5G NR的非独立组网（NSA）模式
具体解释可看5G新无线

网络判断使用了Reachability

方式一：通过CoreTelephony获取网络状态

引入头文件

#import "Reachability.h"
#import <CoreTelephony/CTCarrier.h>
#import <CoreTelephony/CTTelephonyNetworkInfo.h>

开始网络判断：

+ (NSString *)networkStatus{
    Reachability *reachability   = [Reachability reachabilityWithHostName:@"www.apple.com"];
    NetworkStatus internetStatus = [reachability currentReachabilityStatus];
    NSString *net = @"WIFI";
    switch (internetStatus) {
        case ReachableViaWiFi:
            net = @"WIFI";
            break;
        case ReachableViaWWAN:
            net = [self getNetType];   //判断具体类型
            break;
        case NotReachable:
            net = @"当前无网路连接";
        default:
            break;
    }
    NSLog(@"net is %@", net);
    return net;
}

+ (NSString *)getNetType
{
    CTTelephonyNetworkInfo *info = [[CTTelephonyNetworkInfo alloc] init];
    /// 注意：没有SIM卡，值为空
    NSString *currentStatus;
    NSString *currentNet = @"5G";
    if (@available(iOS 12.1, *)) {
        if (info && [info respondsToSelector:@selector(serviceCurrentRadioAccessTechnology)]) {
            NSDictionary *radioDic = [info serviceCurrentRadioAccessTechnology];
            if (radioDic.allKeys.count) {
                currentStatus = [radioDic objectForKey:radioDic.allKeys[0]];
            }
        }
    }else{
        currentStatus = info.currentRadioAccessTechnology;
    }
    
    if ([currentStatus isEqualToString:CTRadioAccessTechnologyGPRS]) {
        currentNet = @"GPRS";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyEdge]) {
        currentNet = @"2.75G EDGE";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyWCDMA]){
        currentNet = @"3G";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyHSDPA]){
        currentNet = @"3.5G HSDPA";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyHSUPA]){
        currentNet = @"3.5G HSUPA";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyCDMA1x]){
        currentNet = @"2G";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyCDMAEVDORev0]){
        currentNet = @"3G";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyCDMAEVDORevA]){
        currentNet = @"3G";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyCDMAEVDORevB]){
        currentNet = @"3G";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyeHRPD]){
        currentNet = @"HRPD";
    }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyLTE]){
        currentNet = @"4G";
    }else if (@available(iOS 14.1, *)) {
        if ([currentStatus isEqualToString:CTRadioAccessTechnologyNRNSA]){
            currentNet = @"5G NSA";
        }else if ([currentStatus isEqualToString:CTRadioAccessTechnologyNR]){
            currentNet = @"5G";
        }
    }
    return currentNet;
}

鉴于评论区反馈iOS14.0.1对5G判断产生的崩溃，这里5G的判断从14.1开始判断(独白：但是官方写着就是14.0，真是个左右为难的问题~)

方式二：通过状态栏获取网络状态(不推荐)

因为私有属性在之后的版本会被取消，不推荐这种方式

- (NSString *)getNetStatusByStatusBar{
    @try {
        NSArray *children;
        UIApplication *app = [UIApplication sharedApplication];
        NSString *state;
        // 全屏
        if ([[app valueForKeyPath:@"_statusBar"] isKindOfClass:NSClassFromString(@"UIStatusBar_Modern")]) {
            children = [[[[app valueForKeyPath:@"_statusBar"] valueForKeyPath:@"_statusBar"] valueForKeyPath:@"foregroundView"] subviews];
            for (UIView *view in children) {
                for (id child in view.subviews) {
                    //wifi
                    if ([child isKindOfClass:NSClassFromString(@"_UIStatusBarWifiSignalView")]) {
                        state = @"wifi";
                    }
                    //2G 3G 4G
                    if ([child isKindOfClass:NSClassFromString(@"_UIStatusBarStringView")]) {
                        if ([[child valueForKey:@"_originalText"] containsString:@"G"]) {
                            state = [child valueForKey:@"_originalText"];
                        }
                    }
                }
            }
        }else {
            children = [[[app valueForKeyPath:@"_statusBar"] valueForKeyPath:@"foregroundView"] subviews];
            for (id child in children) {
                if ([child isKindOfClass:NSClassFromString(@"UIStatusBarDataNetworkItemView")]) {
                    //获取到状态栏
                    switch ([[child valueForKeyPath:@"dataNetworkType"] intValue]) {
                        case 0:
                            state = @"无网络";
                            //无网模式
                            break;
                        case 1:
                            state = @"2G";
                            break;
                        case 2:
                            state = @"3G";
                            break;
                        case 3:
                            state = @"4G";
                            break;
                        case 5:
                            state = @"wifi";
                            break;
                        default:
                            break;
                    }
                }
            }
        }
        return state;
    }
    @catch (NSException * __unused exception) {}
}