目前我正在通过apple reachability.m / .h使用该类，它可以工作，除了它通知我任何更改，我想只通知用户网络是否无法访问。目前，如果我有互联网连接，然后松散网络它告诉我。但是当你重新连接到网络时，它也告诉我，我不想要。我希望它只在有丢失/无网络时告诉我。
我认为这与电话有关：
- (void)viewWillAppear:(BOOL)animated
{
// check for internet connection
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(checkNetworkStatus:)
name:kReachabilityChangedNotification
object:nil];
internetReachable = [[Reachability
reachabilityForInternetConnection] retain];
[internetReachable startNotifier];
// check if a pathway to a random host exists
hostReachable = [[Reachability reachabilityWithHostName:
@"www.google.ca"] retain];
[hostReachable startNotifier];
// now patiently wait for the notification
}
在调用-[NSNotificationCenter addObserver:selector:name:object:]时，该名称是否具有任何其他功能，然后才是名字？这是我第一次使用NSNotificationCenter，所以我不太熟悉这个问题。
编辑：
这是我的checkNetworkStatus功能:(问题是我得到＆＃34; NotReachable＆＃34;因为网络连接回来了，NSAlert多次关闭）
- (void) checkNetworkStatus:(NSNotification *)notice
{
// called after network status changes
NetworkStatus internetStatus = [internetReachable currentReachabilityStatus];
switch (internetStatus)
{
case NotReachable:
{
UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Network Failed" message:@"Please check your connection and try again." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil ];
[alert show];
NSLog(@"The internet is down.");
break;
}
case ReachableViaWiFi:
{
NSLog(@"The internet is working via WIFI.");
break;
}
case ReachableViaWWAN:
{
NSLog(@"The internet is working via WWAN.");
break;
}
}
NetworkStatus hostStatus = [hostReachable currentReachabilityStatus];
switch (hostStatus)
{
case NotReachable:
{
NSLog(@"A gateway to the host server is down.");
break;
}
case ReachableViaWiFi:
{
NSLog(@"A gateway to the host server is working via WIFI.");
break;
}
case ReachableViaWWAN:
{
NSLog(@"A gateway to the host server is working via WWAN.");
break;
}
}
}
答案 0 :(得分：5)
可更改性会在状态发生变化时发送通知，但您对该通知的处理完全取决于您。如果您不想告诉用户网络已恢复，则您不必这样做。
NSNotificationCenter方法中的“name”参数指示您要订阅的通知。当对象发布通知时，它会使用特定名称。
答案 1 :(得分：2)
如果您仅使用IP地址替换www.hostname.com，它只会提醒一次而不是多次。
答案 2 :(得分：1)
我刚刚开始玩Reachability，希望我发现对你有用。
关于重新连接时多个“不可达”，是否可以链接到this？这张海报为远程主机提出了“可达”的定义。我猜测重新连接包时无法成功完成？
另一种可能性是Reachability Readme.txt
重要信息：可访问性必须使用DNS来解析之前的主机名 可以确定该主机的可达性，这可能需要一段时间 某些网络连接。因此，API将返回 在名称解析完成之前无法访问。这种延迟可能是 在某些网络的界面中可见。
也许直接给它IP，看它是否有帮助？
答案 3 :(得分：1)
使用Reachability 2.2，您可以添加
[hostReach connectionRequired];
前
[internetReachable startNotifier];
解决这个问题。
runmad在这里回答了这个问题： https://stackoverflow.com/a/2157858/623260
答案 4 :(得分：0)
我会实现整个Reachability类，根据需要将其绑定到您的代码中，并删除或注释掉Reachability的部分内容。只需逐个删除您不希望收到通知的内容。显然，你需要对obj-c，Reachability类，通知等有一个很好的理解，但是可以做到。
答案 5 :(得分：0)
您可以做的一件事是取消订阅已更改的通知NSNotificationCenter removeObserver ...当您在回调中处理一个时。在返回之前添加观察者。
答案 6 :(得分：0)
我们可以使用此代码检查可达性
添加课程Reachability.h
#import <Foundation/Foundation.h>
#import <SystemConfiguration/SystemConfiguration.h>
typedef enum {
NotReachable = 0,
ReachableViaWiFi,
ReachableViaWWAN
} NetworkStatus;
#define kReachabilityChangedNotification @"kNetworkReachabilityChangedNotification"
@interface Reachability: NSObject
{
BOOL localWiFiRef;
SCNetworkReachabilityRef reachabilityRef;
}
//reachabilityWithHostName- Use to check the reachability of a particular host name.
+ (Reachability*) reachabilityWithHostName: (NSString*) hostName;
//reachabilityWithAddress- Use to check the reachability of a particular IP address.
+ (Reachability*) reachabilityWithAddress: (const struct sockaddr_in*) hostAddress;
//reachabilityForInternetConnection- checks whether the default route is available.
// Should be used by applications that do not connect to a particular host
+ (Reachability*) reachabilityForInternetConnection;
//reachabilityForLocalWiFi- checks whether a local wifi connection is available.
+ (Reachability*) reachabilityForLocalWiFi;
//Start listening for reachability notifications on the current run loop
- (BOOL) startNotifier;
- (void) stopNotifier;
- (NetworkStatus) currentReachabilityStatus;
//WWAN may be available, but not active until a connection has been established.
//WiFi may require a connection for VPN on Demand.
- (BOOL) connectionRequired;
@end
Reachability.m
#import <sys/socket.h>
#import <netinet/in.h>
#import <netinet6/in6.h>
#import <arpa/inet.h>
#import <ifaddrs.h>
#import <netdb.h>
#import <CoreFoundation/CoreFoundation.h>
#import "Reachability.h"
#define kShouldPrintReachabilityFlags 1
static void PrintReachabilityFlags(SCNetworkReachabilityFlags flags, const char* comment)
{
#if kShouldPrintReachabilityFlags
NSLog(@"Reachability Flag Status: %c%c %c%c%c%c%c%c%c %s\n",
(flags & kSCNetworkReachabilityFlagsIsWWAN) ? 'W' : '-',
(flags & kSCNetworkReachabilityFlagsReachable) ? 'R' : '-',
(flags & kSCNetworkReachabilityFlagsTransientConnection) ? 't' : '-',
(flags & kSCNetworkReachabilityFlagsConnectionRequired) ? 'c' : '-',
(flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) ? 'C' : '-',
(flags & kSCNetworkReachabilityFlagsInterventionRequired) ? 'i' : '-',
(flags & kSCNetworkReachabilityFlagsConnectionOnDemand) ? 'D' : '-',
(flags & kSCNetworkReachabilityFlagsIsLocalAddress) ? 'l' : '-',
(flags & kSCNetworkReachabilityFlagsIsDirect) ? 'd' : '-',
comment
);
#endif
}
@implementation Reachability
static void ReachabilityCallback(SCNetworkReachabilityRef target, SCNetworkReachabilityFlags flags, void* info)
{
#pragma unused (target, flags)
NSCAssert(info != NULL, @"info was NULL in ReachabilityCallback");
NSCAssert([(NSObject*) info isKindOfClass: [Reachability class]], @"info was wrong class in ReachabilityCallback");
//We're on the main RunLoop, so an NSAutoreleasePool is not necessary, but is added defensively
// in case someon uses the Reachablity object in a different thread.
NSAutoreleasePool* myPool = [[NSAutoreleasePool alloc] init];
Reachability* noteObject = (Reachability*) info;
// Post a notification to notify the client that the network reachability changed.
[[NSNotificationCenter defaultCenter] postNotificationName: kReachabilityChangedNotification object: noteObject];
[myPool release];
}
- (BOOL) startNotifier
{
BOOL retVal = NO;
SCNetworkReachabilityContext context = {0, self, NULL, NULL, NULL};
if(SCNetworkReachabilitySetCallback(reachabilityRef, ReachabilityCallback, &context))
{
if(SCNetworkReachabilityScheduleWithRunLoop(reachabilityRef, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode))
{
retVal = YES;
}
}
return retVal;
}
- (void) stopNotifier
{
if(reachabilityRef!= NULL)
{
SCNetworkReachabilityUnscheduleFromRunLoop(reachabilityRef, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
}
}
- (void) dealloc
{
[self stopNotifier];
if(reachabilityRef!= NULL)
{
CFRelease(reachabilityRef);
}
[super dealloc];
}
+ (Reachability*) reachabilityWithHostName: (NSString*) hostName;
{
Reachability* retVal = NULL;
SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithName(NULL, [hostName UTF8String]);
if(reachability!= NULL)
{
retVal= [[[self alloc] init] autorelease];
if(retVal!= NULL)
{
retVal->reachabilityRef = reachability;
retVal->localWiFiRef = NO;
}
}
return retVal;
}
+ (Reachability*) reachabilityWithAddress: (const struct sockaddr_in*) hostAddress;
{
SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)hostAddress);
Reachability* retVal = NULL;
if(reachability!= NULL)
{
retVal= [[[self alloc] init] autorelease];
if(retVal!= NULL)
{
retVal->reachabilityRef = reachability;
retVal->localWiFiRef = NO;
}
}
return retVal;
}
+ (Reachability*) reachabilityForInternetConnection;
{
struct sockaddr_in zeroAddress;
bzero(&zeroAddress, sizeof(zeroAddress));
zeroAddress.sin_len = sizeof(zeroAddress);
zeroAddress.sin_family = AF_INET;
return [self reachabilityWithAddress: &zeroAddress];
}
+ (Reachability*) reachabilityForLocalWiFi;
{
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);
Reachability* retVal = [self reachabilityWithAddress: &localWifiAddress];
if(retVal!= NULL)
{
retVal->localWiFiRef = YES;
}
return retVal;
}
#pragma mark Network Flag Handling
- (NetworkStatus) localWiFiStatusForFlags: (SCNetworkReachabilityFlags) flags
{
PrintReachabilityFlags(flags, "localWiFiStatusForFlags");
BOOL retVal = NotReachable;
if((flags & kSCNetworkReachabilityFlagsReachable) && (flags & kSCNetworkReachabilityFlagsIsDirect))
{
retVal = ReachableViaWiFi;
}
return retVal;
}
- (NetworkStatus) networkStatusForFlags: (SCNetworkReachabilityFlags) flags
{
PrintReachabilityFlags(flags, "networkStatusForFlags");
if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
{
// if target host is not reachable
return NotReachable;
}
BOOL retVal = NotReachable;
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
retVal = ReachableViaWiFi;
}
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
retVal = ReachableViaWiFi;
}
}
if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
{
// ... but WWAN connections are OK if the calling application
// is using the CFNetwork (CFSocketStream?) APIs.
retVal = ReachableViaWWAN;
}
return retVal;
}
- (BOOL) connectionRequired;
{
NSAssert(reachabilityRef != NULL, @"connectionRequired called with NULL reachabilityRef");
SCNetworkReachabilityFlags flags;
if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))
{
return (flags & kSCNetworkReachabilityFlagsConnectionRequired);
}
return NO;
}
- (NetworkStatus) currentReachabilityStatus
{
NSAssert(reachabilityRef != NULL, @"currentNetworkStatus called with NULL reachabilityRef");
NetworkStatus retVal = NotReachable;
SCNetworkReachabilityFlags flags;
if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))
{
if(localWiFiRef)
{
retVal = [self localWiFiStatusForFlags: flags];
}
else
{
retVal = [self networkStatusForFlags: flags];
}
}
return retVal;
}
@end
使用
在Apple类中使用直接调用方法 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(checkNetworkStatus:) name:kReachabilityChangedNotification object:nil];
-(void) checkNetworkStatus:(NSNotification *)notice
{
Reachability* internetReachable;
BOOL isInternetActive;
// called after network status changes
NetworkStatus internetStatus = [internetReachable currentReachabilityStatus];
switch (internetStatus)
{
case NotReachable:
{
NSLog(@"The internet is down.");
isInternetActive = NO;
break;
}
case ReachableViaWiFi:
{
NSLog(@"The internet is working via WIFI.");
isInternetActive = YES;
break;
}
case ReachableViaWWAN:
{
NSLog(@"The internet is working via WWAN.");
isInternetActive = YES;
break;
}
}
NetworkStatus hostStatus = [hostReachable currentReachabilityStatus];
switch (hostStatus)
{
case NotReachable:
{
NSLog(@"A gateway to the host server is down.");
// self.hostActive = NO;
break;
}
case ReachableViaWiFi:
{
NSLog(@"A gateway to the host server is working via WIFI.");
// self.hostActive = YES;
break;
}
case ReachableViaWWAN:
{
NSLog(@"A gateway to the host server is working via WWAN.");
// self.hostActive = YES;
break;
}
}
}