iOS判断网络环境

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我们在开发app时很多环境下都需要判断网络所处环境。

判断网络所处环境是很重要的一环，开发Web等网络应用程序的时候，需要确认网络环境，连接情况等信息。如果没有处理它们，是不会通过Apple的审查的。

Apple 的 例程 Reachability 中介绍了取得/检测网络状态的方法。

在你的程序中使用

　　1.Reachability 只须将该例程中的 Reachability.h 和 Reachability.m 拷贝到你的工程中
　　
　　2.然后将 SystemConfiguration.framework 添加进工程 　　

Reachability 中定义了3种网络状态。

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typedefenum {
NotReachable = 0,//无连接
ReachableViaWiFi,//使用3G/GPRS网络
ReachableViaWWAN//使用WiFi网络
} NetworkStatus;

简单判断项目连接

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// 是否wifi
+ (BOOL) IsEnableWIFI {
return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable);
}

// 是否网络连接
+ (BOOL) IsEnableConnection {
return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] != NotReachable);
}

// 是否网络连接
+ (BOOL) IsEnable3G {
return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] == ReachableViaWWAN);
}

于是我们就可以根据网络环境的不同来针对性的写代码了

下面是Apple的Reachability的源代码

Reachability/Reachability.h

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#import <Foundation/Foundation.h>
#import <SystemConfiguration/SystemConfiguration.h>
#import <netinet/in.h>
 
typedef enum : NSInteger {
    NotReachable = 0,
    ReachableViaWiFi,
    ReachableViaWWAN
} NetworkStatus;
 
#pragma mark IPv6 Support
//Reachability fully support IPv6.  For full details, see ReadMe.md.
 
 
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 *)hostAddress;
 
/*!
 * Checks whether the default route is available. Should be used by applications that do not connect to a particular host.
 */
+ (instancetype)reachabilityForInternetConnection;
 
 
#pragma mark reachabilityForLocalWiFi
//reachabilityForLocalWiFi has been removed from the sample.  See ReadMe.md for more information.
//+ (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/Reachability.m

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#import <arpa/inet.h>
#import <ifaddrs.h>
#import <netdb.h>
#import <sys/socket.h>
#import <netinet/in.h>
 
#import <CoreFoundation/CoreFoundation.h>
 
#import "Reachability.h"
 
#pragma mark IPv6 Support
//Reachability fully support IPv6.  For full details, see ReadMe.md.
 
 
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
{
    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;
        }
        else {
            CFRelease(reachability);
        }
    }
    return returnValue;
}
 
 
+ (instancetype)reachabilityWithAddress:(const struct sockaddr *)hostAddress
{
    SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, hostAddress);
 
    Reachability* returnValue = NULL;
 
    if (reachability != NULL)
    {
        returnValue = [[self alloc] init];
        if (returnValue != NULL)
        {
            returnValue->_reachabilityRef = reachability;
        }
        else {
            CFRelease(reachability);
        }
    }
    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: (const struct sockaddr *) &zeroAddress];
}
 
#pragma mark reachabilityForLocalWiFi
//reachabilityForLocalWiFi has been removed from the sample.  See ReadMe.md for more information.
//+ (instancetype)reachabilityForLocalWiFi
 
 
 
#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)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))
    {
        returnValue = [self networkStatusForFlags:flags];
    }
    
    return returnValue;
}
 
 
@end


Reachability/main.m

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#import <UIKit/UIKit.h>
 
#import "APLAppDelegate.h"
 
int main(int argc, char *argv[])
{
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([APLAppDelegate class]));
    }
}