iPhone判断是否接入网络

在这里介绍一种较为简单的判断是否连接网络的方法，首先要引入Reachability.h和.m文件，没有这两个文件的话，google之。然后在***AppDelegate.h中声明如下：

Obj-c代码  

1.     NetworkStatus remoteHostStatus;   
2.     NetworkStatus internetConnectionStatus;   
3.     NetworkStatus localWiFiConnectionStatus;   
4.   
5. ...   
6.   
7. //Network   
8. @property NetworkStatus remoteHostStatus;   
9. @property NetworkStatus internetConnectionStatus;   
10. @property NetworkStatus localWiFiConnectionStatus;   
11. - (void) registerNetworkChecking;   
12. - (void) updateNetworkStatus;  

  NetworkStatus remoteHostStatus;
        NetworkStatus internetConnectionStatus;
        NetworkStatus localWiFiConnectionStatus;

...

//Network
@property NetworkStatus remoteHostStatus;
@property NetworkStatus internetConnectionStatus;
@property NetworkStatus localWiFiConnectionStatus;
- (void) registerNetworkChecking;
- (void) updateNetworkStatus;

然后在.m中实现：

Obj-c代码  

1. - (void) registerNetworkChecking   
2. {   
3.     [[Reachability sharedReachability] setHostName:@"www.baidu.com"];   
4.     [[NSNotificationCenter defaultCenter] addObserver:self   
5.                                              selector:@selector(reachabilityChanged:)   
6.                                                  name:@"kNetworkReachabilityChangedNotification"  
7.                                                object:nil];   
8.     //[self updateNetworkStatus];   
9.        
10. }   
11. #pragma mark NetworkStatus Notification   
12. - (void)reachabilityChanged:(NSNotification *)note   
13. {   
14.     //////NSLog(@"reachabilityChanged");   
15.     [self updateNetworkStatus];   
16. }   
17.   
18. - (void)updateNetworkStatus   
19. {   
20.     // Query the SystemConfiguration framework for the state of the device's network connections.   
21.     self.remoteHostStatus           = [[Reachability sharedReachability] remoteHostStatus];   
22.     self.internetConnectionStatus   = [[Reachability sharedReachability] internetConnectionStatus];   
23.     self.localWiFiConnectionStatus  = [[Reachability sharedReachability] localWiFiConnectionStatus];       
24. }  

- (void) registerNetworkChecking
{
        [[Reachability sharedReachability] setHostName:@"www.baidu.com"];
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                                                         selector:@selector(reachabilityChanged:)
                                                                                                 name:@"kNetworkReachabilityChangedNotification"
                                                                                           object:nil];
        //[self updateNetworkStatus];
        
}
#pragma mark NetworkStatus Notification
- (void)reachabilityChanged:(NSNotification *)note
{
        //////NSLog(@"reachabilityChanged");
    [self updateNetworkStatus];
}

- (void)updateNetworkStatus
{
        // Query the SystemConfiguration framework for the state of the device's network connections.
        self.remoteHostStatus           = [[Reachability sharedReachability] remoteHostStatus];
        self.internetConnectionStatus   = [[Reachability sharedReachability] internetConnectionStatus];
        self.localWiFiConnectionStatus  = [[Reachability sharedReachability] localWiFiConnectionStatus];        
}

在需要判断的地方用：

Obj-c代码  

1. ***AppDelegate *appDelegate = (***AppDelegate *)[[UIApplication sharedApplication] delegate];   
2. [appDelegate registerNetworkChecking];     
3. if (appDelegate.remoteHostStatus == NotReachable)   
4. {   
5.       //未联网   
6. }   
7. else   
8. {   
9.       //联网   
10. }