在开发ios应用是我匀经常要使用网络，还得监控网络的连接情况，当网络发生改变时进行对应的事件处理工作。下面就讲解一下利用Reachability进行网络边连接情况监测的使用方法。
要使用Reachability进行网络监控必须先导进Reachability.h和Reachability.m两个方件。
在.h文件中声明一个全局的Reachability类，代码如下：
#import
#import "Reachability.h"
@interface AppDelegate : UIResponder {
Reachability *hostReach;
}
@property (strong, nonatomic) UIWindow *window;
@end
在.m文件中加入对应的代码
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
//监测网络情况
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(reachabilityChanged:)
name: kReachabilityChangedNotification
object: nil];
//初始化Reachability类，并添加一个监测的网址。
hostReach = [Reachability reachabilityWithHostName:@"http://blog.sina.com.cn/u/2526279194"];
//开始监测
[hostReach startNotifier];
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
#pragma mark - 监测网络情况，当网络发生改变时会调用
- (void)reachabilityChanged:(NSNotification *)note {
Reachability* curReach = [note object];
NSParameterAssert([curReach isKindOfClass: [Reachability class]]);
NetworkStatus status = [curReach currentReachabilityStatus];
if (status == NotReachable) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil
message:@"NotReachable"
delegate:nil
cancelButtonTitle:@"YES" otherButtonTitles:nil];
[alert show];
alert = nil;
}
}