IOS检测网络连接状态

使用之前请从Apple网站下载示例：点此下载

然后将Reachability.h 和 Reachability.m 加到自己的项目中，并引用 SystemConfiguration.framework，就可以使用了。

Reachability 中定义了3种网络状态：

// the network state of the device for Reachability 1.5.

typedef enum {

    NotReachable = 0,  //无连接

    ReachableViaCarrierDataNetwork, //使用3G/GPRS网络

    ReachableViaWiFiNetwork  //使用WiFi网络

} NetworkStatus;



// the network state of the device for Reachability 2.0.

typedef enum {

    NotReachable = 0,  //无连接

    ReachableViaWiFi,  //使用3G/GPRS网络

    ReachableViaWWAN  //使用WiFi网络

} NetworkStatus;

 

比如检测某一特定站点的接续状况，可以使用下面的代码：

Reachability *r = [Reachability reachabilityWithHostName:@“www.apple.com”];

switch ([r currentReachabilityStatus]) {

    case NotReachable:

        // 没有网络连接

        break;

    case ReachableViaWWAN:

        // 使用3G网络

        break;

    case ReachableViaWiFi:

        // 使用WiFi网络

        break;

}

 

检测当前网络环境：

// 是否wifi

+ (BOOL) IsEnableWIFI {

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

}



// 是否3G

+ (BOOL) IsEnable3G {

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

}

 

连接状态实时通知

网络连接状态的实时检查，通知在网络应用中也是十分必要的。接续状态发生变化时，需要及时地通知用户。由于Reachability1.5版与2.0版有一些变化，这里分开来说明使用方法。

Reachability 1.5

// My.AppDelegate.h



#import "Reachability.h"



@interface MyAppDelegate : NSObject <UIApplicationDelegate> {

    NetworkStatus remoteHostStatus;

}



@property NetworkStatus remoteHostStatus;



@end



// My.AppDelegate.m



#import "MyAppDelegate.h"



@implementation MyAppDelegate



@synthesize remoteHostStatus;



// 更新网络状态

- (void)updateStatus {

    self.remoteHostStatus = [[Reachability sharedReachability] remoteHostStatus];

}



// 通知网络状态

- (void)reachabilityChanged:(NSNotification *)note {

    [self updateStatus];

    if (self.remoteHostStatus == NotReachable) {

        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"AppName", nil) message:NSLocalizedString(@"NotReachable", nil)

        delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];

        [alert show];

        [alert release];

    }

}



// 程序启动器，启动网络监视

- (void)applicationDidFinishLaunching:(UIApplication *)application {



    // 设置网络检测的站点

    [[Reachability sharedReachability] setHostName:@"www.apple.com"];

    [[Reachability sharedReachability] setNetworkStatusNotificationsEnabled:YES];

    // 设置网络状态变化时的通知函数

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:)

                                                 name:@"kNetworkReachabilityChangedNotification" object:nil];

    [self updateStatus];

}



- (void)dealloc {

    // 删除通知对象

    [[NSNotificationCenter defaultCenter] removeObserver:self];

    [window release];

    [super dealloc];

}

 

Reachability 2.0

// MyAppDelegate.h



@class Reachability;



@interface MyAppDelegate : NSObject <UIApplicationDelegate> {

    Reachability  *hostReach;

}



@end



// MyAppDelegate.m

- (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:@"AppName""

                                                        message:@"NotReachable"

                                                       delegate:nil

                                              cancelButtonTitle:@"YES" otherButtonTitles:nil];

        [alert show];

        [alert release];

    }

}



- (void)applicationDidFinishLaunching:(UIApplication *)application {

    // ...



    // 监测网络情况

    [[NSNotificationCenter defaultCenter] addObserver:self

                                          selector:@selector(reachabilityChanged:)

                                          name: kReachabilityChangedNotification

                                          object: nil];

    hostReach = [[Reachability reachabilityWithHostName:@"www.google.com"] retain];

    [hostReach startNotifer];

    // ...

}

 

本人转自：易飞扬的博客