- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
//開啟網(wǎng)絡(luò)狀況的監(jiān)聽
//來訂閱實時的網(wǎng)絡(luò)狀態(tài)變化通知。導(dǎo)入Reachability.h頭文件，然后注冊一個對象來訂閱網(wǎng)絡(luò)狀態(tài)變化的信息，網(wǎng)絡(luò)狀態(tài)變化的信息名稱為kReachabilityChanged-Notification
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];
//通過檢查某個主機能否訪問來判斷當(dāng)前網(wǎng)絡(luò)是否可用：
self.hostReach = [Reachability reachabilityWithHostName:@"www.baidu.com"] ;
//開始監(jiān)聽，會啟動一個run loop
[self.hostReach startNotifier];
}
-(void)reachabilityChanged:(NSNotification *)note{
Reachability *currReach = [note object];
NSParameterAssert([currReach isKindOfClass:[Reachability class]]);
//對連接改變做出響應(yīng)處理動作
NetworkStatus status = [currReach currentReachabilityStatus];
//如果沒有連接到網(wǎng)絡(luò)就彈出提醒實況
self.isReachable = YES;
if(status == NotReachable){
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"網(wǎng)絡(luò)連接異常" message:nil delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil];
[alert show];
[alert release];
self.isReachable = NO;
return;
}
if (status==kReachableViaWiFi||status==kReachableViaWWAN) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"網(wǎng)絡(luò)連接信息" message:@"網(wǎng)絡(luò)連接正常" delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil];
// [alert show];
[alert release];
self.isReachable = YES;
}
}

-(void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:YES];
AppDelegate *appDlg = (AppDelegate *)[[UIApplication sharedApplication] delegate];
if(appDlg.isReachable){
NSLog(@"網(wǎng)絡(luò)已連接");//執(zhí)行網(wǎng)絡(luò)正常時的代碼
}
else{
NSLog(@"網(wǎng)絡(luò)連接異常");//執(zhí)行網(wǎng)絡(luò)異常時的代碼
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"網(wǎng)絡(luò)連接異常" message:nil delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil];
[alert show];
[alert release];
}
}

-(void)afn{
//1.創(chuàng)建網(wǎng)絡(luò)狀態(tài)監(jiān)測管理者
AFNetworkReachabilityManager *manger = [AFNetworkReachabilityManager sharedManager];
//開啟監(jiān)聽，記得開啟，不然不走block
[manger startMonitoring];
//2.監(jiān)聽改變
[manger setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
/*
AFNetworkReachabilityStatusUnknown = -1,
AFNetworkReachabilityStatusNotReachable = 0,
AFNetworkReachabilityStatusReachableViaWWAN = 1,
AFNetworkReachabilityStatusReachableViaWiFi = 2,
*/
switch (status) {
case AFNetworkReachabilityStatusUnknown:
NSLog(@"未知");
break;
case AFNetworkReachabilityStatusNotReachable:
NSLog(@"沒有網(wǎng)絡(luò)");
break;
case AFNetworkReachabilityStatusReachableViaWWAN:
NSLog(@"3G|4G");
break;
case AFNetworkReachabilityStatusReachableViaWiFi:
NSLog(@"WiFi");
break;
default:
break;
}
}];
}