ios網絡開發 網絡狀態檢查

網絡連接中用到的類：

一.Reachability 

    1.添加 Reachability 的.h和.m文件，再添加SystemConfiguration.framework。

    2.Reachability中定義了三種網絡狀態：

  typedef Num{

NotReachable = 0,  //無連接

ReachableViaWiFi,  //使用3G/GPRS網絡

ReachableViaWWAN   //使用WiFi網絡

       }NetworkStatus;

     3.示例：

  Reachability *reachability = [Reachablity  reachabilityWithHostName:@"www.baidu.com"];

  switch([reachabilityStatus]){

case  NotReachable:

//TODO 

break; 

case  ReachableViaWiFi:

//TODO  

break; 

case  ReachableViaWWAN:

//TODO  

break;  

 } 

      4.檢查當前網絡環境

程序啟動時，如果想檢測可用的網絡環境，可以像這樣來使用

  //是否wifi

+ (BOOL)isEnableWIFI 

{

return ([[Reachability reachabiliyForLocalWIFI] currentReachabilityStatus] != NotReachable); 

  }

 

   //是否3G

+ (BOOL)isEnable3G

{

return ([[Reachability reachabiliyForInternetConnetion] currentReachabilityStatus] != NotReachable); 

   }

 

   示例：

- (void)viewWillAppear:(BOOL)animated

{ 

  if (([Reachability reachabiliyForInternetConnetion].currentReachabilityStatus == NotReachable) && [Reachability                         reachabiliyForLocalWIFI].currentReachabilityStatus == NotReachable))

{

self.navigationItem.hidesBackButton = YES;

[self.navigationItem setLeftBarButtonItem:nil animated:NO]; 

} 

 

 } 

 

       5.鏈接狀態的實時通知

實時檢查，持續狀態發生變化時，需要及時地通知用戶：

 

           Reachability  
          1.5版本 
          
 
          // 
          MyAppDelegate.h 
          
 
          
 
          #import  
          " 
          Reachability 
          " 
          
 
          
 
          @interface MyAppDelegate:NSObject<UIApplicationDelegate> 
          
{ 
          
     
          
} 
          
 
          
@property NetworkStatus remoteHostStatus; 
          
 
          
 
          @end  
         

 

 //MyAppDelegate.m

 
          
 
          #import  
          " 
          MyAppDelegate.h 
          " 
          
 
          
 
          @implementation MyAppDelegate 
          
 
          @synthesize remoteHostStatus; 
          
 
          
 
          // 
          更新網絡狀態 
          
- ( 
          void)updateStatus 
          
{ 
          
    self.remoteHostStatus = [[Reachability sharedReachability] remoteHostStatus]; 
          
} 
          
 
          
 
          // 
          通知網絡狀態 
          
- ( 
          void)reachabilityChanged:(NSNotification *)note 
          
{ 
          
    [self updateStatus]; 
          
     
          if (self.remoteHostStatus == NotReachable) 
          
   { 
          
       UIAlert *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString( 
          @" 
          AppName 
          ",nil) 
          
  message: NSLocalizedString ( 
          @" 
          NotReachable 
          ",nil); 
          
   
          delegate:nil cancelButtonTitle: 
          @" 
          OK 
          "  
          
  otherButtonTitles:nil]; 
          
 
          
   [alert show]; 
          
   [alert release]; 
          
    } 
          
} 
          
 
          
 
          
 
          // 
          程序啟動器，啟動網絡監視 
          
- ( 
          void)applicationDidFinishLaunching:(UIApplication *)application 
          
{ 
          
    
          // 
          設置網絡監測的站點 
          
   [[Reachability sharedReachability] setHostName: 
          @" 
          www.baidu.com 
          "]; 
          
   [[Reachability sharedReachability] setNetworkStatusNotificationsEnabled:YES]; 
          
 
          
    
          // 
          設置網絡狀態變化時的通知函數 
          
   [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:)  
          
name: 
          @" 
          kNetworkReachabilityChangedNotification 
          "  
          object:nil]; 
          
   [self updateStatus]; 
          
 
          
 
          
} 
          
 
          
- ( 
          void)dealloc 
          
{ 
          
     
          // 
          刪除通知對象 
          
    [[NSNotificationCenter defaultCenter] removeObserver:self]; 
          
    [window release]; 
          
    [super dealloc]; 
          
} 
         

 

            Reachability  
          2.0版本 
          
 
          // 
          MyAppDelegate.h 
          
 
          
 
          #import  
          " 
          Reachability 
          " 
          
 
          @class Reachability; 
          
 
          @interface MyAppDelegate:NSObject<UIApplicationDelegate> 
          
{ 
          
     Reachability *hostReach; 
          
} 
          
 
          
 
          
 
          @end  
          
  
          
  
          // 
          MyAppDelegate.m 
          
 
          
 
          #import  
          " 
          MyAppDelegate.h 
          " 
          
 
          
 
          @implementation MyAppDelegate 
          
 
          
 
          // 
          通知網絡狀態 
          
- ( 
          void)reachabilityChanged:(NSNotification *)note 
          
{ 
          
    Reachability *currentReach = [note  
          object]; 
          
    NSParameterAssert([currentReach isKindOfClass:[Reachability  
          class]]); 
          
    NetworkStatus status = [currentReach currentReachabilityStatus];  
          
 
          
     
          if (status == NotReachable) 
          
   { 
          
       UIAlert *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString( 
          @" 
          AppName 
          ",nil) 
          
  message: NSLocalizedString ( 
          @" 
          NotReachable 
          ",nil); 
          
   
          delegate:nil cancelButtonTitle: 
          @" 
          YES 
          "  
          
  otherButtonTitles:nil]; 
          
 
          
   [alert show]; 
          
   [alert release]; 
          
    } 
          
} 
          
 
          
 
          
 
          // 
          程序啟動器，啟動網絡監視 
          
- ( 
          void)applicationDidFinishLaunching:(UIApplication *)application 
          
{ 
          
    
          // 
          ....

    
          // 
          監測網絡情況 
          
   [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:)  
          
name: 
          @" 
          kNetworkReachabilityChangedNotification 
          "  
          object:nil]; 
          
  hostReach = [[Reachability reachabilityWithHostName: 
          @" 
          www.baidu.com 
          "] retain]; 
          
  
          // 
           hostReach startNotifer]; 
    
          // 
          ... 
          
 
          
 
          
} 
         

 

二、其他常用的類。

 1.NSURL

 2.NSURLRequest

 3.NSMutableURLRequest 是NSURLRequest的子類，可以設置一些請求參數

 4.NSURLResponse 

 5.NSError