网络请求:

1. 在进行网络请求前 先判断网络是否可用

系统方法

#import <SystemConfiguration/SCNetworkReachability.h>
#pragma mark 判断设备能否上网
+ (BOOL)isNet {
    struct sockaddr_storage zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.ss_len = sizeof(zeroAddress);
    zeroAddress.ss_family = AF_INET;
    SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);
    SCNetworkReachabilityFlags flags;
    BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);
    CFRelease(defaultRouteReachability);
    if (!didRetrieveFlags) {
        return NO;
    }
    BOOL isReachable = flags & kSCNetworkFlagsReachable;
    BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
    return (isReachable&&!needsConnection) ? YES : NO;
}

AF

(参考)

- (void)monitorNetworking
{
    [[AFNetworkReachabilityManager sharedManager] startMonitoring];
    [[AFNetworkReachabilityManager sharedManager] setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
        switch (status) {
            case -1:
                NSLog(@"未知网络");
                break;
            case 0:
                NSLog(@"网络不可达");
                break;
            case 1:
            {
                NSLog(@"GPRS网络");
            }
                break;
            case 2:
            {
                NSLog(@"wifi网络");
            }
                break;
            default:
                break;
        }
        if (status == AFNetworkReachabilityStatusReachableViaWWAN || status == AFNetworkReachabilityStatusReachableViaWiFi) {
            NSLog(@"有网");
        }else{
            NSLog(@"没网");
        }
    }];
}

2. 在进行网络请求前 先判断网络类型, 按需反馈

(参考)

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

#import <CoreTelephony/CTTelephonyNetworkInfo.h>
- (NSString *)getNetType
{
       CTTelephonyNetworkInfo *info = [[CTTelephonyNetworkInfo alloc] init];
            NSString *currentStatus = info.currentRadioAccessTechnology;
            if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyGPRS"]) {
                netconnType = @"GPRS";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyEdge"]) {
                netconnType = @"2.75G EDGE";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyWCDMA"]){
                netconnType = @"3G";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyHSDPA"]){
                netconnType = @"3.5G HSDPA";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyHSUPA"]){
                netconnType = @"3.5G HSUPA";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyCDMA1x"]){
                netconnType = @"2G";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyCDMAEVDORev0"]){
                netconnType = @"3G";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyCDMAEVDORevA"]){
                netconnType = @"3G";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyCDMAEVDORevB"]){
                netconnType = @"3G";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyeHRPD"]){
                netconnType = @"HRPD";
            }else if ([currentStatus isEqualToString:@"CTRadioAccessTechnologyLTE"]){
                netconnType = @"4G";
            }
}