AFNetWorking监听网络状态

 AFNetworkReachabilityManager *manager = [AFNetworkReachabilityManager sharedManager];
    [manager startMonitoring];
    [manager setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
        switch (status) {
            case AFNetworkReachabilityStatusUnknown:
                NSLog(@"未识别的网络");
                break;
                
            case AFNetworkReachabilityStatusNotReachable:{
                UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:@"当前网络不可用,请检查网络设置" preferredStyle:UIAlertControllerStyleAlert];
                UIAlertAction *action = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:nil];
                [alert addAction:action];
                [[UIApplication sharedApplication].keyWindow.rootViewController presentViewController:alert animated:YES completion:nil];
            }
               
                break;
                
            case AFNetworkReachabilityStatusReachableViaWWAN:
                NSLog(@"2G,3G,4G...的网络");
                break;
                
            case AFNetworkReachabilityStatusReachableViaWiFi:
                NSLog(@"wifi的网络");
                break;
            default:
                break;
        }
    }];