使用 Reachability 获取网络状态
Reachability
source https://developer.apple.com/library/ios/samplecode/Reachability/Introduction/Intro.html
reachability 为苹果官方demo提供的一个检测网络状态的代码,下载源码后本人对其进行了修改,修改后源码:
reachability.h + reachability.m
#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; /*! * 测试是否能连接网 */ + (NetworkStatus)isExistNetwork; @end
#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; } + (NetworkStatus)isExistNetwork { NetworkStatus isExistenceNetwork; //单例 static Reachability *reachability = nil; //服务器地址选择了百度 if (reachability == nil) { reachability = [Reachability reachabilityWithHostName:@"www.baidu.com"]; } switch([reachability currentReachabilityStatus]) { case NotReachable: isExistenceNetwork = NotReachable; break; case ReachableViaWWAN: isExistenceNetwork = ReachableViaWWAN; break; case ReachableViaWiFi: isExistenceNetwork = ReachableViaWiFi; break; } return isExistenceNetwork; } @end
直接使用下面的代码来得到网络信息,是单例模式,无需担心浪费内存
[Reachability isExistNetwork];
其返回3个枚举值,判断一下即可,
NotReachable, ReachableViaWiFi, ReachableViaWWAN
使用通知来监听网络状态
1.定义属性(strong)
@property (nonatomic, strong) Reachability *hostReachability;
@property (nonatomic, strong) Reachability *internetReachability;
@property (nonatomic, strong) Reachability *wifiReachability;
2.指定监听的方法
- (void) reachabilityChanged:(NSNotification *)note
{
Reachability *tmp = [note object];
NSLog(@"%d", [tmp currentReachabilityStatus]);
}
3.初始化以及监听
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(reachabilityChanged:)
name:kReachabilityChangedNotification
object:nil];
NSString *remoteHostName = @"www.baidu.com";
_hostReachability = [Reachability reachabilityWithHostName:remoteHostName];
[_hostReachability startNotifier];
_internetReachability = [Reachability reachabilityForInternetConnection];
[_internetReachability startNotifier];
_wifiReachability = [Reachability reachabilityForLocalWiFi];
[_wifiReachability startNotifier];
