iOS 网络状态Reachablity

引入第三方Reachability.h和Reachability.m文件，以及导入库文件SystemConfiguration.framework

Reachability.h文件

/*

     File: Reachability.h

 Abstract: Basic demonstration of how to use the SystemConfiguration Reachablity APIs.

  Version: 3.5

 

 Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple

 Inc. ("Apple") in consideration of your agreement to the following

 terms, and your use, installation, modification or redistribution of

 this Apple software constitutes acceptance of these terms.  If you do

 not agree with these terms, please do not use, install, modify or

 redistribute this Apple software.

 

 In consideration of your agreement to abide by the following terms, and

 subject to these terms, Apple grants you a personal, non-exclusive

 license, under Apple's copyrights in this original Apple software (the

 "Apple Software"), to use, reproduce, modify and redistribute the Apple

 Software, with or without modifications, in source and/or binary forms;

 provided that if you redistribute the Apple Software in its entirety and

 without modifications, you must retain this notice and the following

 text and disclaimers in all such redistributions of the Apple Software.

 Neither the name, trademarks, service marks or logos of Apple Inc. may

 be used to endorse or promote products derived from the Apple Software

 without specific prior written permission from Apple.  Except as

 expressly stated in this notice, no other rights or licenses, express or

 implied, are granted by Apple herein, including but not limited to any

 patent rights that may be infringed by your derivative works or by other

 works in which the Apple Software may be incorporated.

 

 The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

 THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

 FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

 

 IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL

 OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,

 MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED

 AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),

 STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE

 POSSIBILITY OF SUCH DAMAGE.

 

 Copyright (C) 2014 Apple Inc. All Rights Reserved.

 

 */

#import <Foundation/Foundation.h>

#import <SystemConfiguration/SystemConfiguration.h>

#import <netinet/in.h>

typedef enum : NSInteger {

NotReachable = 0,

ReachableViaWiFi,

ReachableViaWWAN

} NetworkStatus;

extern NSString *kReachabilityChangedNotification;

@interface Reachability : NSObject

/*!

 * Use to check the reachability of a given host name.

 */

+ (instancetype)reachabilityWithHostName:(NSString *)hostName;

/*!

 * Use to check the reachability of a given IP address.

 */

+ (instancetype)reachabilityWithAddress:(const struct sockaddr_in *)hostAddress;

/*!

 * Checks whether the default route is available. Should be used by applications that do not connect to a particular host.

 */

+ (instancetype)reachabilityForInternetConnection;

/*!

 * Checks whether a local WiFi connection is available.

 */

+ (instancetype)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文件

/*

     File: Reachability.m

 Abstract: Basic demonstration of how to use the SystemConfiguration Reachablity APIs.

  Version: 3.5

 

 Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple

 Inc. ("Apple") in consideration of your agreement to the following

 terms, and your use, installation, modification or redistribution of

 this Apple software constitutes acceptance of these terms.  If you do

 not agree with these terms, please do not use, install, modify or

 redistribute this Apple software.

 

 In consideration of your agreement to abide by the following terms, and

 subject to these terms, Apple grants you a personal, non-exclusive

 license, under Apple's copyrights in this original Apple software (the

 "Apple Software"), to use, reproduce, modify and redistribute the Apple

 Software, with or without modifications, in source and/or binary forms;

 provided that if you redistribute the Apple Software in its entirety and

 without modifications, you must retain this notice and the following

 text and disclaimers in all such redistributions of the Apple Software.

 Neither the name, trademarks, service marks or logos of Apple Inc. may

 be used to endorse or promote products derived from the Apple Software

 without specific prior written permission from Apple.  Except as

 expressly stated in this notice, no other rights or licenses, express or

 implied, are granted by Apple herein, including but not limited to any

 patent rights that may be infringed by your derivative works or by other

 works in which the Apple Software may be incorporated.

 

 The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

 THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

 FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

 

 IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL

 OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,

 MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED

 AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),

 STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE

 POSSIBILITY OF SUCH DAMAGE.

 

 Copyright (C) 2014 Apple Inc. All Rights Reserved.

 

 */

#import <arpa/inet.h>

#import <ifaddrs.h>

#import <netdb.h>

#import <sys/socket.h>

#import <CoreFoundation/CoreFoundation.h>

#import "Reachability.h"

NSString *kReachabilityChangedNotification = @"kNetworkReachabilityChangedNotification";

#pragma mark - Supporting functions

#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

}

static void ReachabilityCallback(SCNetworkReachabilityRef target, SCNetworkReachabilityFlags flags, void* info)

{

#pragma unused (target, flags)

NSCAssert(info != NULL, @"info was NULL in ReachabilityCallback");

NSCAssert([(__bridge NSObject*) info isKindOfClass: [Reachability class]], @"info was wrong class in ReachabilityCallback");

    Reachability* noteObject = (__bridge Reachability *)info;

    // Post a notification to notify the client that the network reachability changed.

    [[NSNotificationCenter defaultCenter] postNotificationName: kReachabilityChangedNotification object: noteObject];

}

#pragma mark - Reachability implementation

@implementation Reachability

{

BOOL _alwaysReturnLocalWiFiStatus; //default is NO

SCNetworkReachabilityRef _reachabilityRef;

}

+ (instancetype)reachabilityWithHostName:(NSString *)hostName

{

Reachability* returnValue = NULL;

SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithName(NULL, [hostName UTF8String]);

if (reachability != NULL)

{

returnValue= [[self alloc] init];

if (returnValue != NULL)

{

returnValue->_reachabilityRef = reachability;

returnValue->_alwaysReturnLocalWiFiStatus = NO;

}

}

return returnValue;

}

+ (instancetype)reachabilityWithAddress:(const struct sockaddr_in *)hostAddress

{

SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr *)hostAddress);

Reachability* returnValue = NULL;

if (reachability != NULL)

{

returnValue = [[self alloc] init];

if (returnValue != NULL)

{

returnValue->_reachabilityRef = reachability;

returnValue->_alwaysReturnLocalWiFiStatus = NO;

}

}

return returnValue;

}

+ (instancetype)reachabilityForInternetConnection

{

struct sockaddr_in zeroAddress;

bzero(&zeroAddress, sizeof(zeroAddress));

zeroAddress.sin_len = sizeof(zeroAddress);

zeroAddress.sin_family = AF_INET;

    

return [self reachabilityWithAddress:&zeroAddress];

}

+ (instancetype)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* returnValue = [self reachabilityWithAddress: &localWifiAddress];

if (returnValue != NULL)

{

returnValue->_alwaysReturnLocalWiFiStatus = YES;

}

    

return returnValue;

}

#pragma mark - Start and stop notifier

- (BOOL)startNotifier

{

BOOL returnValue = NO;

SCNetworkReachabilityContext context = {0, (__bridge void *)(self), NULL, NULL, NULL};

if (SCNetworkReachabilitySetCallback(_reachabilityRef, ReachabilityCallback, &context))

{

if (SCNetworkReachabilityScheduleWithRunLoop(_reachabilityRef, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode))

{

returnValue = YES;

}

}

    

return returnValue;

}

- (void)stopNotifier

{

if (_reachabilityRef != NULL)

{

SCNetworkReachabilityUnscheduleFromRunLoop(_reachabilityRef, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

}

}

- (void)dealloc

{

[self stopNotifier];

if (_reachabilityRef != NULL)

{

CFRelease(_reachabilityRef);

}

}

#pragma mark - Network Flag Handling

- (NetworkStatus)localWiFiStatusForFlags:(SCNetworkReachabilityFlags)flags

{

PrintReachabilityFlags(flags, "localWiFiStatusForFlags");

NetworkStatus returnValue = NotReachable;

if ((flags & kSCNetworkReachabilityFlagsReachable) && (flags & kSCNetworkReachabilityFlagsIsDirect))

{

returnValue = ReachableViaWiFi;

}

    

return returnValue;

}

- (NetworkStatus)networkStatusForFlags:(SCNetworkReachabilityFlags)flags

{

PrintReachabilityFlags(flags, "networkStatusForFlags");

if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)

{

// The target host is not reachable.

return NotReachable;

}

    NetworkStatus returnValue = NotReachable;

if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)

{

/*

         If the target host is reachable and no connection is required then we'll assume (for now) that you're on Wi-Fi...

         */

returnValue = 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...

             */

            returnValue = ReachableViaWiFi;

        }

    }

if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)

{

/*

         ... but WWAN connections are OK if the calling application is using the CFNetwork APIs.

         */

returnValue = ReachableViaWWAN;

}

    

return returnValue;

}

- (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 SCNetworkReachabilityRef");

NetworkStatus returnValue = NotReachable;

SCNetworkReachabilityFlags flags;

    

if (SCNetworkReachabilityGetFlags(_reachabilityRef, &flags))

{

if (_alwaysReturnLocalWiFiStatus)

{

returnValue = [self localWiFiStatusForFlags:flags];

}

else

{

returnValue = [self networkStatusForFlags:flags];

}

}

    

return returnValue;

}

@end

在需要判断网络状态的.h页面引入Reachability.h头文件，并自定义属性conn

#import <UIKit/UIKit.h>

#import "Reachability.h"

@interface ViewController : UIViewController

@property (nonatomic, strong) Reachability *conn;

@end

在需要判断网络状态的.m页面

/*

 Reachability使用场景

 在网络应用中，需要对用户设备的网络状态进行实时监控，有两个目的：

 

 （1）让用户了解自己的网络状态，防止一些误会（比如怪应用无能）

 

 （2）根据用户的网络状态进行智能处理，节省用户流量，提高用户体验

 

 　　WIFI\3G网络：自动下载高清图片

 

 　　低速网络：只下载缩略图

 

 　　没有网络：只显示离线的缓存数据

 */

/*

 Reachability的使用步骤

 

 1.添加框架SystemConfiguration.framework

 2.添加源代码 (导入Reachability.h和 Reachability.m)

 3.引入头文件Reachability.h

 

 */

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    

   /* NSNotificationCenter是专门供程序中不同类间的消息通信而设置的

   参数介绍:

    

    addObserver:　观察者，即在什么地方接收通知;

    

   　       selector:　收到通知后调用何种方法;

    

   　       name：　通知的名字，也是通知的唯一标示，编译器就通过这个找到通知的。

    

            Reachability的连接状态发生改变时,将会发送一个kReachabilityChangedNotification通知给默认的通知中心

           

            object：传递的参数

    

    */

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

         self.conn = [Reachability reachabilityForInternetConnection];

     //让Reachability对象开启被监听状态

         [self.conn startNotifier];

    

}

     

- (void)dealloc

 {

    [self.conn stopNotifier];

    [[NSNotificationCenter defaultCenter] removeObserver:self];

}

- (void)networkStateChange

{

    [self checkNetworkState];

}

- (void)checkNetworkState

 {

        // 1.检测wifi状态

         Reachability *wifi = [Reachability reachabilityForLocalWiFi];

    

         // 2.检测手机是否能上网络(WIFI\3G\2.5G)

        Reachability *conn = [Reachability reachabilityForInternetConnection];

    // NSLog(@"44");

        // 3.判断网络状态

    // currentReachabilityStatus方法获取网络连接状态，如果网络连接状态返回NotReachable，则表明这种类型的网络暂未连接。

     //有WiFi 和手机网络 用 WiFi

     //没有WiFi用手机网络

     //没网络 就 没有 网络

        if ([wifi currentReachabilityStatus] != NotReachable) {

            //有wifi

                 NSLog(@"有wifi");

        

             } else if ([conn currentReachabilityStatus] != NotReachable) {

                 //没有使用wifi, 使用手机自带网络进行上网

                     NSLog(@"使用手机自带网络进行上网(2g/3g/4g)");

            

                 } else { //没有网络

                     

                         NSLog(@"没有网络");

                    }

     

     

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end