我发现使用SimplePingHelper库很简单。

示例代码:chrishulbert/SimplePingHelper (GitHub)

这是Swift 3.0和异步的。大多数答案是同步解决方案，这将阻塞你的主线程，如果你有一个非常慢的连接。

这个解决方案更好，但并不完美，因为它依赖于谷歌来检查连接，所以可以随意使用另一个URL。

func checkInternetConnection(completionHandler:@escaping (Bool) -> Void)
{
    if let url = URL(string: "http://www.google.com/")
    {
        var request = URLRequest(url: url)
        request.httpMethod = "HEAD"
        request.cachePolicy = .reloadIgnoringLocalAndRemoteCacheData
        request.timeoutInterval = 5

        let tast = URLSession.shared.dataTask(with: request, completionHandler:
        {
            (data, response, error) in

            completionHandler(error == nil)
        })
        tast.resume()
    }
    else
    {
        completionHandler(true)
    }
}

创建一个AFNetworkReachabilityManager对象，并使用以下代码跟踪网络连通性

self.reachabilityManager = [AFNetworkReachabilityManager managerForDomain:@"yourDomain"];
[self.reachabilityManager startMonitoring];
[self.reachabilityManager setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
        switch (status) {
            case AFNetworkReachabilityStatusReachableViaWWAN:
            case AFNetworkReachabilityStatusReachableViaWiFi:
                break;
            case AFNetworkReachabilityStatusNotReachable:
                break;
            default:
                break;
        }
    }];

使用Apple的Reachability代码，我创建了一个函数，可以正确地检查这一点，而无需包含任何类。

在你的项目中包含SystemConfiguration.framework。

进行一些导入:

#import <sys/socket.h>
#import <netinet/in.h>
#import <SystemConfiguration/SystemConfiguration.h>

现在只需调用这个函数:

/*
Connectivity testing code pulled from Apple's Reachability Example: https://developer.apple.com/library/content/samplecode/Reachability
 */
+(BOOL)hasConnectivity {
    struct sockaddr_in zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.sin_len = sizeof(zeroAddress);
    zeroAddress.sin_family = AF_INET;

    SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)&zeroAddress);
    if (reachability != NULL) {
        //NetworkStatus retVal = NotReachable;
        SCNetworkReachabilityFlags flags;
        if (SCNetworkReachabilityGetFlags(reachability, &flags)) {
            if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
            {
                // If target host is not reachable
                return NO;
            }

            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
                return YES;
            }


            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
                    return YES;
                }
            }

            if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
            {
                // ... but WWAN connections are OK if the calling application
                //     is using the CFNetwork (CFSocketStream?) APIs.
                return YES;
            }
        }
    }

    return NO;
}

这是为你测试的iOS 5。

步骤1:在项目中添加Reachability类。 步骤2:导入Reachability类 步骤3:创建下面的函数 - (BOOL)checkNetConnection { self.internetReachability =[可达性reachabilityForInternetConnection]; [self.internetReachability startNotifier]; NetworkStatus netStatus = [self.internetReachability currentReachabilityStatus]; switch (netStatus) { 案例NotReachable: ｛ 返回NO; } 案例ReachableViaWWAN: ｛ 返回YES; } 案例ReachableViaWiFi: ｛ 返回YES; } } } 步骤4:调用函数如下所示: 如果(![self checkNetConnection]) { [GlobalFunctions showAlert: @”“ 信息:@“请连接到互联网!” canBtntitle:零 otherBtnTitle: @“Ok”); 返回; } 其他的 ｛ 日志。V(“internet is connected”，“ok”); }

Swift 5及以后:

public class Reachability {
    class func isConnectedToNetwork() -> Bool {
        var zeroAddress = sockaddr_in()
        zeroAddress.sin_len = UInt8(MemoryLayout<sockaddr_in>.size)
        zeroAddress.sin_family = sa_family_t(AF_INET)

        guard let defaultRouteReachability = withUnsafePointer(to: &zeroAddress, {
            $0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
                SCNetworkReachabilityCreateWithAddress(nil, $0)
            }
        }) else {
            return false
        }

        var flags: SCNetworkReachabilityFlags = []
        if !SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags) {
            return false
        }

        let isReachable = flags.contains(.reachable)
        let needsConnection = flags.contains(.connectionRequired)

        return (isReachable && !needsConnection)
    }

像这样调用这个类:

if Reachability.isConnectedToNetwork() == true {
    // Do something
} else {
    // Do something
}