如何检查服务器的可达性[重复]

Question

可能重复：
Undefined symbols for architecture armv7: “_SCNetworkReachabilityCreateWithAddress”

我尝试了一些我在这里找到的东西，但都没有奏效。我将 Apple 的 reachability.h 和 .m 文件添加到我的项目中。我正在尝试测试 mogul 服务器的可达性，以下是我在实际程序中使用的代码：

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(handleNetworkChange:) name:kReachabilityChangedNotification
object:nil];

reach = [Reachability reachabilityForInternetConnection];
[reach startNotifier];

NetworkStatus remoteHostStatus = [reach currentReachabilityStatus];

if (remoteHostStatus == NotReachable) {
    NSLog(@"no");
    textTest.text = @"Can't reach it";
}
else if(remoteHostStatus == ReachableViaWiFi || remoteHostStatus == ReachableViaWWAN){
    NSLog(@"Yes");
    textTest.text = @"Got it";
}
testServer.hidden = YES;

....

-(void)handleNetworkChange:(NSNotification *)notice{
    NetworkStatus remoteHostStatus = [reach currentReachabilityStatus];

    if (remoteHostStatus == NotReachable) {
        NSLog(@"no");
        textTest.text = @"Can't get it";
    }
    else if(remoteHostStatus == ReachableViaWiFi || remoteHostStatus == ReachableViaWWAN){
       NSLog(@"Got it");
       textTest.text = @"Got it";
    }
}

在 .h 文件中：

@property (retain, nonatomic) Reachability *reach;

....

-(void)handleNetworkChange:(NSNotification *)notice;

每次我尝试编译和运行时，都会得到以下结果：

Ld /Users/ConorMccallion/Library/Developer/Xcode/DerivedData/newClient-aunayptutxnlhjeoflldefcmybpk/Build/Products/Debug-iphonesimulator/newClient.app/newClient normal i386
    cd /Volumes/TRAVELDRIVE/Reseaech/ClientSide/newClient
    setenv IPHONEOS_DEPLOYMENT_TARGET 6.0
    setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk -L/Users/ConorMccallion/Library/Developer/Xcode/DerivedData/newClient-aunayptutxnlhjeoflldefcmybpk/Build/Products/Debug-iphonesimulator -F/Users/ConorMccallion/Library/Developer/Xcode/DerivedData/newClient-aunayptutxnlhjeoflldefcmybpk/Build/Products/Debug-iphonesimulator -filelist /Users/ConorMccallion/Library/Developer/Xcode/DerivedData/newClient-aunayptutxnlhjeoflldefcmybpk/Build/Intermediates/newClient.build/Debug-iphonesimulator/newClient.build/Objects-normal/i386/newClient.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=6.0 -framework UIKit -framework Foundation -framework CoreGraphics -o /Users/ConorMccallion/Library/Developer/Xcode/DerivedData/newClient-aunayptutxnlhjeoflldefcmybpk/Build/Products/Debug-iphonesimulator/newClient.app/newClient

Undefined symbols for architecture i386:
  "_SCNetworkReachabilityCreateWithAddress", referenced from:
      +[Reachability reachabilityWithAddress:] in ViewController.o
      +[Reachability reachabilityWithAddress:] in Reachability.o
  "_SCNetworkReachabilityCreateWithName", referenced from:
      +[Reachability reachabilityWithHostName:] in ViewController.o
      +[Reachability reachabilityWithHostName:] in Reachability.o
  "_SCNetworkReachabilityGetFlags", referenced from:
      -[Reachability connectionRequired] in ViewController.o
      -[Reachability currentReachabilityStatus] in ViewController.o
      -[Reachability connectionRequired] in Reachability.o
      -[Reachability currentReachabilityStatus] in Reachability.o
  "_SCNetworkReachabilityScheduleWithRunLoop", referenced from:
      -[Reachability startNotifier] in ViewController.o
      -[Reachability startNotifier] in Reachability.o
  "_SCNetworkReachabilitySetCallback", referenced from:
      -[Reachability startNotifier] in ViewController.o
      -[Reachability startNotifier] in Reachability.o
  "_SCNetworkReachabilityUnscheduleFromRunLoop", referenced from:
      -[Reachability stopNotifier] in ViewController.o
      -[Reachability stopNotifier] in Reachability.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

这可能是显而易见的，因此我们将不胜感激。谢谢

Answer 1

如果要检查特定主机的可达性，可以使用以下代码，

Reachability *reach = [Reachability reachabilityWithHostName:@"www.apple.com"];

您可以在此处将您的服务器名称作为主机名来检查可达性。它应该工作。 查看apple documentation 了解更多详情。

对于您收到的错误消息，请尝试将SystemConfiguration.framework 添加到项目中。如果这没有帮助，请查看此Undefined symbols for architecture armv7: "_SCNetworkReachabilityCreateWithAddress"。

Answer 2

关于 didFinishLaunchingWithOptions 方法的 put：

self.internetReach= [Reachability reachabilityWithHostName:@"your host name e.g.www.apple.com"];

[internetReach startNotifier];


[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];


[self performSelector:@selector(reachabilityChanged:) withObject:[NSNotification notificationWithName:kReachabilityChangedNotification object:internetReach]];

这将调用下面的方法

- (void)reachabilityChanged:(NSNotification*)note

{

Reachability* curReach = [note object];
NSParameterAssert([curReach isKindOfClass: [Reachability class]]);

if(curReach == self.internetReach)
{
    NetworkStatus netStatus = [curReach currentReachabilityStatus];
    switch (netStatus)
    {
        case ReachableViaWiFi:
        {            
            isInternetConnectionAvilable=YES;
            if(isNetworkNotifierCalledOnce)
            {
                UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"Message!" message:@"Internet Available Now" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
                [alert show];
                [alert release];
            }
            break;
        }

        case NotReachable:
        {     

            isInternetConnectionAvilable=NO;

            UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"Message!" message:@"No Internet Connectivity" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];

            [alert show];

            [alert release];

            break;
        }
    }

}

isNetworkNotifierCalledOnce=YES;

}