Question

我目前正在使用以下内容检查Wi-Fi是否适用于我的应用程序：

#import <SystemConfiguration/SystemConfiguration.h>
static inline BOOL addressReachable(const struct sockaddr_in *hostAddress);

BOOL localWiFiAvailable()
{
    struct sockaddr_in localWifiAddress;
    bzero(&localWifiAddress, sizeof(localWifiAddress));
    localWifiAddress.sin_len = sizeof(localWifiAddress);
    localWifiAddress.sin_family = AF_INET;
    // IN_LINKLOCALNETNUM is defined in <netinet/in.h> as 169.254.0.0
    localWifiAddress.sin_addr.s_addr = htonl(IN_LINKLOCALNETNUM);

    return addressReachable(&localWifiAddress);
}

static inline BOOL addressReachable(const struct sockaddr_in *hostAddress)
{
    const SCNetworkReachabilityRef target =
          SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault,
                                                 (const struct sockaddr *)hostAddress);
    if (target != NULL)
    {
        SCNetworkReachabilityFlags flags = 0;
        const BOOL reachable = SCNetworkReachabilityGetFlags(target, &flags);
        CFRelease(target);
        return reachable && (flags & kSCNetworkFlagsReachable);
    }
    return NO;
}

然而，当iPhone仅连接到蜂窝网络而不是Wi-Fi网络时，这不会返回NO。有谁知道如何解决这个问题？

修改

所以这就是我最终使用的内容：

#import <arpa/inet.h> // For AF_INET, etc.
#import <ifaddrs.h> // For getifaddrs()
#import <net/if.h> // For IFF_LOOPBACK

BOOL localWiFiAvailable()
{
    struct ifaddrs *addresses;
    struct ifaddrs *cursor;
    BOOL wiFiAvailable = NO;
    if (getifaddrs(&addresses) != 0) return NO;

    cursor = addresses;
    while (cursor != NULL) {
        if (cursor -> ifa_addr -> sa_family == AF_INET
            && !(cursor -> ifa_flags & IFF_LOOPBACK)) // Ignore the loopback address
        {
            // Check for WiFi adapter
            if (strcmp(cursor -> ifa_name, "en0") == 0) {
                wiFiAvailable = YES;
                break;
            }
        }
        cursor = cursor -> ifa_next;
    }

    freeifaddrs(addresses);
    return wiFiAvailable;
}

谢谢“unforgiven”（显然是马特·布朗）。

Answer 1

首先，修改addressReachable方法。而不是

return reachable && (flags & kSCNetworkFlagsReachable);

添加以下内容：

BOOL isReachable = ((flags & kSCNetworkFlagsReachable) != 0);
BOOL needsConnection = ((flags & kSCNetworkFlagsConnectionRequired) != 0);
return (isReachable && !needsConnection) ? YES : NO;

这是检查可用连接的正确方法。现在，如果您想清楚地区分蜂窝和wifi，请修改您的方法以返回int并使用以下

BOOL isReachable = ((flags & kSCNetworkFlagsReachable) != 0);
BOOL needsConnection = ((flags & kSCNetworkFlagsConnectionRequired) != 0);

if(isReachable && !needsConnection) // connection is available 
{

   // determine what type of connection is available
   BOOL isCellularConnection = ((flags & kSCNetworkReachabilityFlagsIsWWAN) != 0);
   NSString *wifiIPAddress = [self getWiFiIPAddress];

   if(isCellularConnection) 
        return 1; // cellular connection available

   if(wifiIPAddress)
       return 2; // wifi connection available
}
else
   return 0; // no connection at all

getWiFiIPAddress方法由Matt Brown提供，可以找到here。

还有一件事。 kSCNetworkReachabilityFlagsIsDirect标志可以告诉您网络流量是通过网关还是直接到达。这在某些情况下可能会有所帮助。

代码在设备上正常运行。在模拟器上，当您通过以太网电缆连接时，它将声明您通过wifi连接，并且如果您通过wifi连接将声明没有连接。

Answer 2

查看此链接： http://developer.apple.com/iphone/library/samplecode/Reachability/

您必须是注册开发人员才能下载代码示例。而且这很重要！ Reachability API适用于3.0+ SDK，它会为较低版本崩溃。

BTW，新的HIG所有依赖WiFi连接的应用都必须提醒用户没有，即如果设备没有连接到Wifi，请让用户知道。

Answer 3

Swift版

import Foundation
import SystemConfiguration

public class Reachability {
    class func isInternetAvailable() -> Bool {
        let IPaddress = "google.com"//WebServicesUtil.sharedInstance.getHostIPAddress()
        if let host_name = IPaddress.cStringUsingEncoding(NSASCIIStringEncoding) {
            let reachability  =
                SCNetworkReachabilityCreateWithName(kCFAllocatorDefault, host_name).takeRetainedValue()

            var flags: SCNetworkReachabilityFlags = 0
            if SCNetworkReachabilityGetFlags(reachability, &flags) == 0 {
                return false
            }

            let isReachable = (flags & UInt32(kSCNetworkFlagsReachable)) != 0
            let needsConnection = (flags & UInt32(kSCNetworkFlagsConnectionRequired)) != 0

            return (isReachable && !needsConnection)
        }
        else {
            return false
        }
    }
}

Answer 4

查看Apple提供的Reachability类。这允许您检查设备当前具有的连接，Wifi，蜂窝或无。您甚至可以在连接发生变化时注册通知。

不幸的是，谷歌此刻对我不利，但谷歌搜索“iPhone可达性”将为您提供所需。

Answer 5

-(Bool)isDataSourceAvailableNow
{ 

    BOOL isDataSourceAvailable;

    bool success = false;

    const char *host_name = [@"www.google.com" cStringUsingEncoding:NSASCIIStringEncoding];

    SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithName(NULL,  host_name);

    if (reachability) 
    {

        SCNetworkReachabilityFlags flags;
        success = SCNetworkReachabilityGetFlags(reachability, &flags);

        isDataSourceAvailable = success && (flags & kSCNetworkFlagsReachable) &&  !(flags & kSCNetworkFlagsConnectionRequired);

        CFRelease(reachability);

    }  return isDataSourceAvailable;

}

如何使用iPhone SDK检查本地Wi-Fi（不仅仅是蜂窝连接）？

修改

5 个答案: