关于官方Reachability Demo理解

1. 示例说明：此示例用于演示关于如何使用SystemConfiguratio Reachalility程序接口来判定相关的网络连接状态及状态变化，所以在使用此示例中的Reachability.(h/m)文件于自有的项目中的前提是必须引入SystemConfiguration.framework。

2. 首选分析Reachability.h文件：

-> 首先引入<SystemConfiguration/SystemConfiguration.h>

#import <SystemConfiguration/SystemConfiguration.h>

-> 定义代表网络状态的枚举类型NetworkStatus：

// 定义网络请求可到达状态typedef enum {    NotReachable = 0,   // 不可到达    ReachableViaWiFi,   // 通过WiFi可到达    ReachableViaWWAN    // 通过无线广域网可到达(WWAN，即Wireless Wide Area Network，无线广域网。)} NetworkStatus;

-> 宏定义关于网络连接变更的通知标识名称：

#define kReachabilityChangedNotification @"kNetworkReachabilityChangedNotification"

-> 定义相关属性：

BOOL localWiFiRef;    // 用来保存创建测试连接返回的引用SCNetworkReachabilityRef reachabilityRef;

 

-> 声明各相关的方法：

// 用于检查网络请求是否可到达指定的主机名+ (Reachability*) reachabilityWithHostName: (NSString*) hostName;

// 用于检查网络请求是否可到达指定的IP地址+ (Reachability*) reachabilityWithAddress: (const struct sockaddr_in*) hostAddress;

// 用于检查路由连接是否有效+ (Reachability*) reachabilityForInternetConnection;

// 用于检查本地的WiFi连接是否有效+ (Reachability*) reachabilityForLocalWiFi;

// 在当前程序的运行回路中开始监听网络请求可到达的通知- (BOOL) startNotifier;- (void) stopNotifier;

// 当前网络请求可到达状态- (NetworkStatus) currentReachabilityStatus;

// 当前网络请求可到达状态- (NetworkStatus) currentReachabilityStatus;

// 连接需求- (BOOL) connectionRequired;

- (void) applicationDidFinishLaunching: (UIApplication* )application {    [[NSNotificationCenter defaultCenter]　　addObserver:self　　　　　　　　　　　　　　　　　　　　　　　　　　　 selector:@selector(reachabilityChanged:)　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　name:kReachabilityChangedNotification　　　　　　　　　　　　　　　　　　　　　　　　　　　　　object:nil];　　    hostReach = [[Reachability reachabilityWithHostName:@"www.apple.com"] retain];    [hostReach startNotifier];    internetReach = [[Reachability reachabilityForInternetConnection] retain];    [internetReach startNotifier];    [self updateInterfaceWithReachability:internetReach];    wifiReach = [[Reachability reachabilityForLocalWiFi] retain];    [wifiReach startNotifier];     [self updateInterfaceWithReachability:wifiReach];    [window makeKeyAndVisible];}- (void)reachabilityChanged:(NSNotification *)note{    Reachability *curReach = [note object];    NSParameterAssert([curReach isKindOfClass:[Reachability class]]);    [self updateInterfaceWithReachability:curReach];}- (void)updateInterfaceWithReachability:(Reachability *)curReach{    if (curReach == hostReach)    {        [self configureTextField:remoteHostStateField imageView:remoteHostIcon reachability:curReach];        NetworkStatus netStatus = [curReach currentReachabilityStates];        BOOL connectionRequired = [curReach connectionRequired];                summaryLabel.hidden = (netStatus != ReachabilityViaWWAN);        NSString *baseLabel = @"";        if (connectionRequired)        {            baseLabel = @"Cellular data network is available.\n Internet traffic will be routed through it after a connection is established.";        }        else　　　　 {            baseLabel = @"Cellular data network is active.\n Internet traffic will be routed through it.";        }        summaryLabel.text = baseLabel;    }    if (curReach == internetReach)    {        [self configureTextField:internetConnectionStatusField imageView:internetConnectionIcon reachability:curReach];    }    if (curReach == wifiReach)    {        [self configureTextField:localWiFiConnectionStatusField imageView:localWiFiConnectionIcon reachability:curReach];    }}- (void)configureTextField:(UITextField *)textField imageView:(UIImageView *)imageView reachability:(Reachability *)curReach{    NetworkStatus netStatus = [curReach currentReachabilityStatus];    BOOL connectionRequired = [curReach connectionRequired];    NSString *statusString = @"";    switch (netStatus)    {        case NotReachable:        {            statusString = @"Access Not Available";            imageView.image = [UIImage imageNamed:@"stop-32.png"];            connectionRequired = NO;            break;        }        case ReachableViaWWAN:        {            statusString = @"Reachable WWAN";            imageView.image = [UIImage imageNamed:@"WWAN5.png"];                    break;        }        case ReachableViaWiFi:        {            statusString = @"";            imageView.image = [UIImage imageNamed:@"Airport.png"];            break;        }    }    if (connectionRequired)    {        statusString = [NSString stringWithFormat:@"%@, Connection Required", statusString];    }    textField.text = statusString;}

 

. 关于Reachability.m

参考此链接：http://blog.sina.com.cn/s/blog_65a8ab5d010110w5.html

4. 关于Reachability的使用：