IOS使用Reachability实时检测网络连接状况

//在程序的启动处，开启通知

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

//.....

//开启网络状况的监听

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(reachabilityChanged:)

name: kReachabilityChangedNotification

object: nil];

hostReach =
[[Reachability reachabilityWithHostName:@"www.google.com"] retain];//可以以多种形式初始化

[hostReach startNotifier];
//开始监听,会启动一个run loop

[self updateInterfaceWithReachability: hostReach];

//.....

}

// 连接改变

- (void) reachabilityChanged: (NSNotification* )note

{

Reachability* curReach = [note object];

NSParameterAssert([curReach isKindOfClass:
[Reachability class]]);

[self updateInterfaceWithReachability:
curReach];

}

//处理连接改变后的情况

- (void) updateInterfaceWithReachability: (Reachability*) curReach

{

//对连接改变做出响应的处理动作。

NetworkStatus status = [curReach currentReachabilityStatus];

if (status == NotReachable) { //没有连接到网络就弹出提实况

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"My
App Name"

message:@"NotReachable"

delegate:nil

cancelButtonTitle:@"YES" otherButtonTitles:nil];

[alert show];

[alert release];

}

}