检查Internet连接的可用性(iOS) Xcode 8, Swift 3.0

这是一个简单的方法来检查网络可用性，如我们的设备是否连接到任何网络。我已经成功地将其翻译为Swift 3.0，这里是最终的代码。现有的Apple Reachability类和其他第三方库似乎太复杂了，无法翻译到Swift中。 这适用于3G、4G和WiFi连接。 不要忘记在你的项目构建器中添加“SystemConfiguration.framework”。

//Create new swift class file Reachability in your project.
import SystemConfiguration
public class InternetReachability {

class func isConnectedToNetwork() -> Bool {
   var zeroAddress = sockaddr_in(sin_len: 0, sin_family: 0, sin_port: 0, sin_addr: in_addr(s_addr: 0), sin_zero: (0, 0, 0, 0, 0, 0, 0, 0))
   zeroAddress.sin_len = UInt8(sizeofValue(zeroAddress))
   zeroAddress.sin_family = sa_family_t(AF_INET)
   let defaultRouteReachability = withUnsafePointer(&zeroAddress) {
          SCNetworkReachabilityCreateWithAddress(nil, UnsafePointer($0)).takeRetainedValue()
   }
   var flags: SCNetworkReachabilityFlags = 0
   if SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags) == 0 {
          return false
   }
   let isReachable = (flags & UInt32(kSCNetworkFlagsReachable)) != 0
   let needsConnection = (flags & UInt32(kSCNetworkFlagsConnectionRequired)) != 0

   return isReachable && !needsConnection
  }
}

// Check network connectivity from anywhere in project by using this code.
 if InternetReachability.isConnectedToNetwork() == true {
         print("Internet connection OK")
  } else {
         print("Internet connection FAILED")
  }

我喜欢把事情简单化。我的做法是:

//Class.h
#import "Reachability.h"
#import <SystemConfiguration/SystemConfiguration.h>

- (BOOL)connected;

//Class.m
- (BOOL)connected
{
    Reachability *reachability = [Reachability reachabilityForInternetConnection];
    NetworkStatus networkStatus = [reachability currentReachabilityStatus];
    return networkStatus != NotReachable;
}

然后，每当我想要查看是否有连接时，我就使用这个:

if (![self connected]) {
    // Not connected
} else {
    // Connected. Do some Internet stuff
}

这个方法不会等待网络状态的改变来执行操作。它只在您要求时测试状态。

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
}

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。

- (void)viewWillAppear:(BOOL)animated
{
    NSString *URL = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];

    return (URL != NULL ) ? YES : NO;
}

或者使用Reachability类。

使用iPhone SDK有两种方法来检查网络可用性:

1. 检查“谷歌”页面是否打开。

2. 可达性类

有关更多信息，请参考Reachability (Apple Developer)。

这曾经是正确的答案，但现在已经过时了，因为你应该订阅通知以获得可访问性。这个方法同步检查:

你可以使用苹果的Reachability类。它还可以让你检查是否启用了Wi-Fi:

Reachability* reachability = [Reachability sharedReachability];
[reachability setHostName:@"www.example.com"];    // Set your host name here
NetworkStatus remoteHostStatus = [reachability remoteHostStatus];

if (remoteHostStatus == NotReachable) { }
else if (remoteHostStatus == ReachableViaWiFiNetwork) { }
else if (remoteHostStatus == ReachableViaCarrierDataNetwork) { }

Reachability类并没有随SDK一起发布，而是作为这个Apple示例应用程序的一部分。只需下载它，并复制Reachability.h/m到您的项目。另外，您必须将SystemConfiguration框架添加到您的项目中。