没有互联网连接时,无法调用可达性 unreachableBlock

Reachability unreachableBlock not getting called when there is no internet connection

这是我的代码,

Reachability *internetReachable = [Reachability reachabilityWithHostname:@"www.google.com"];


internetReachable.reachableBlock = ^(Reachability*reach)`
{

    NSLog(@"REACHABLE!");



};

internetReachable.unreachableBlock = ^(Reachability*reach){

    NSLog(@"UNREACHABLE!");


};
[internetReachable startNotifier];

当 wifi 关闭时,无法调用无法访问的块。有帮助吗?

试试这个。对我有用。

Reachability *reachability = [Reachability reachabilityWithHostname:@"www.google.com"];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityDidChange:) name:kReachabilityChangedNotification object:nil];
    [reachability startNotifier];


- (void)reachabilityDidChange:(NSNotification *)notification
{
    Reachability *reachability = (Reachability *)[notification object];
    if ([reachability isReachable])
    {
        // network reachable
    }
    else
    {
        // show alert with network error (unreachable)
    }
}

这段代码对我有用,

Reachability *reachability = [Reachability reachabilityForInternetConnection];
NetworkStatus currentStatus = [reachability currentReachabilityStatus];
if(currentStatus!=NotReachable){
    // network reachable
}
else{
  //reachable
}

我会给你详细的解决方案。

首先我添加了可达性类。

Reachability.h

#import <Foundation/Foundation.h>
#import <SystemConfiguration/SystemConfiguration.h>
#import <netinet/in.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");
    NSCAssert([(__bridge 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 = (__bridge 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, (__bridge void * _Nullable)(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];
        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];
        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

然后我将它添加到 GlobalShareClass

GlobalShareClass.h

#import "Reachability.h"
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>

@interface GlobalShareClass : NSObject

+ (GlobalShareClass *)sharedInstance;
+ (BOOL)isConnectedInternet;
+ (void)showAlertController:(NSString *)strAltTit :(NSString *)strAltMsg passViewController:(UIViewController *)view;

@end

GlobalShareClass.m

#import "GlobalShareClass.h"

@implementation GlobalShareClass

+ (GlobalShareClass *)sharedInstance {
   static GlobalShareClass* _shareInstane = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _shareInstane = [[GlobalShareClass alloc] init];
    });
    return _shareInstane;
}

+ (BOOL)isConnectedInternet {
    Reachability *r = [Reachability reachabilityWithHostName:@"www.google.com"];
    NetworkStatus internetStatus = [r currentReachabilityStatus];
    if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN)) {
        return NO;
    }
    return YES;
}

+ (void)showAlertController:(NSString *)strAltTit :(NSString *)strAltMsg passViewController:(UIViewController *)view{
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:strAltTit message:strAltMsg preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *actionOK = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
    }];
    [alert addAction:actionOK];
    [view presentViewController:alert animated:YES completion:nil];
}

然后在ViewController

中调用GlobalShareCalss

ViewController.h

#import <UIKit/UIKit.h>
#import "GlobalShareClass.h"

@interface ViewController : UIViewController{
      GlobalShareClass *globalShare;
}

- (IBAction)actionCheckInternet:(id)sender;

@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController


- (void)viewDidLoad {

    globalShare = [GlobalShareClass sharedInstance];
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


#pragma mark - UIButton Action method

- (IBAction)actionCheckInternet:(id)sender {
      if([GlobalShareClass isConnectedInternet]) {
            .....//Your Code
      }
      else{
            [GlobalShareClass showAlertController:@"No Internet Connection" :nil passViewController:self];
      }
}

@end