#import "AppDelegate.h"#import "ViewController.h"#import "Reachability.h"@interface AppDelegate (){}@property (nonatomic,retain)Reachability *res;@end@implementation AppDelegate- (void)dealloc{    [_window release];    [_res release];    [_viewController release];    [super dealloc];}-(void)change:(NSNotificationCenter *)notify{//当网络发生变化的时候，都会触发这个事件    NSLog(@"%@",notify);}- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    //添加网络变化的通知    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(change:) name:kReachabilityChangedNotification object:nil];    self.res=[Reachability reachabilityWithHostName:@"http://www.baidu.com"];    [self.res startNotifier];//开始监听网络请求的变化            self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];    // Override point for customization after application launch.    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];    self.window.rootViewController = self.viewController;    [self.window makeKeyAndVisible];    return YES;}

、-(void)viewWillAppear:(BOOL)animated{    [super viewWillAppear:animated];    if([Reachability reachabilityForLocalWiFi].currentReachabilityStatus==NotReachable&&[[Reachability reachabilityForInternetConnection] currentReachabilityStatus]==NotReachable){        NSLog(@" not  work");    } }-(void)PdNetwork{    Reachability *r=[Reachability reachabilityWithHostName:@"http://www.baidu.com"];    switch ([r currentReachabilityStatus]) {        case NotReachable:            NSLog(@"not work");            break;        case ReachableViaWiFi:            NSLog(@"wifi");            break;        case ReachableViaWWAN:{            NSLog(@"wan");        }            break;        default:            break;    }}