https://developer.apple.com/library/ios/#samplecode/Reachability/Introduction/Intro.html

我下载的是vertion2.2

开发Web等网络应用程序的时候，需要确认网络环境，连接情况等信息。如果没有处理它们，是不会通过Apple的审查的。

Reachability

Apple 的 例程 Reachability 中介绍了取得/检测网络状态的方法。

在你的程序中使用

1、Reachability 只须将该例程中的 Reachability.h 和 Reachability.m 拷贝到你的工程中； 2、然后将 SystemConfiguration.framework 添加进工程。

Reachability 中定义了3种网络状态。

typedefenum {

NotReachable = 0,//无连接

ReachableViaWiFi,//使用3G/GPRS网络

ReachableViaWWAN//使用WiFi网络

} NetworkStatus;

简单判断项目连接：

// 是否wifi

+ (BOOL) IsEnableWIFI {

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

}

// 是否网络连接

+ (BOOL) IsEnableConnection {

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

}

// 是否网络连接

+ (BOOL) IsEnable3G {

return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] == ReachableViaWWAN);

}

下面是监听整个项目网络例子：

/*

File: ReachabilityAppDelegate.m

Abstract: The application's controller.

Version: 2.2

Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Inc.

("Apple") in consideration of your agreement to the following terms, and your

use, installation, modification or redistribution of this Apple software

constitutes acceptance of these terms.  If you do not agree with these terms,

please do not use, install, modify or redistribute this Apple software.

In consideration of your agreement to abide by the following terms, and subject

to these terms, Apple grants you a personal, non-exclusive license, under

Apple's copyrights in this original Apple software (the "Apple Software"), to

use, reproduce, modify and redistribute the Apple Software, with or without

modifications, in source and/or binary forms; provided that if you redistribute

the Apple Software in its entirety and without modifications, you must retain

this notice and the following text and disclaimers in all such redistributions

of the Apple Software.

Neither the name, trademarks, service marks or logos of Apple Inc. may be used

to endorse or promote products derived from the Apple Software without specific

prior written permission from Apple.  Except as expressly stated in this notice,

no other rights or licenses, express or implied, are granted by Apple herein,

including but not limited to any patent rights that may be infringed by your

derivative works or by other works in which the Apple Software may be

incorporated.

The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

COMBINATION WITH YOUR PRODUCTS.

IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR

DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF

CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF

APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Copyright (C) 2010 Apple Inc. All Rights Reserved.

*/

#import "ReachabilityAppDelegate.h"

#import "Reachability.h"

@implementation ReachabilityAppDelegate

- (void) configureTextField: (UITextField*) textField imageView: (UIImageView*) imageView reachability: (Reachability*) curReach

{

    NetworkStatus netStatus = [curReach currentReachabilityStatus];

    BOOL connectionRequired= [curReach connectionRequired];

    NSString* statusString= @"";

    switch (netStatus)

    {

        case NotReachable:

        {

            statusString = @"Access Not Available";

            imageView.image = [UIImage imageNamed: @"stop-32.png"] ;

            //Minor interface detail- connectionRequired may return yes, even when the host is unreachable.  We cover that up here...

            connectionRequired= NO;

            break;

        }

        case ReachableViaWWAN:

        {

            statusString = @"Reachable WWAN";

            imageView.image = [UIImage imageNamed: @"WWAN5.png"];

            break;

        }

        case ReachableViaWiFi:

        {

             statusString= @"Reachable WiFi";

            imageView.image = [UIImage imageNamed: @"Airport.png"];

            break;

      }

    }

    if(connectionRequired)

    {

        statusString= [NSString stringWithFormat: @"%@, Connection Required", statusString];

    }

    textField.text= statusString;

}

- (void) updateInterfaceWithReachability: (Reachability*) curReach

{

    if(curReach == hostReach)

	{

		[self configureTextField: remoteHostStatusField imageView: remoteHostIcon reachability: curReach];

        NetworkStatus netStatus = [curReach currentReachabilityStatus];

        BOOL connectionRequired= [curReach connectionRequired];

        summaryLabel.hidden =(netStatus != ReachableViaWWAN);

        NSString* baseLabel=  @"";

        if(connectionRequired)

        {

            baseLabel=  @"Cellular data network is available.\n  Internet traffic will be routed through it after a connection is established.";

        }

        else

        {

            baseLabel=  @"Cellular data network is active.\n  Internet traffic will be routed through it.";

        }

        summaryLabel.text= baseLabel;

    }

	if(curReach == internetReach)

	{

		[self configureTextField: internetConnectionStatusField imageView: internetConnectionIcon reachability: curReach];

	}

	if(curReach == wifiReach)

	{

		[self configureTextField: localWiFiConnectionStatusField imageView: localWiFiConnectionIcon reachability: curReach];

	}

}

//Called by Reachability whenever status changes.

- (void) reachabilityChanged: (NSNotification* )note

{

	Reachability* curReach = [note object];

	NSParameterAssert([curReach isKindOfClass: [Reachability class]]);

	[self updateInterfaceWithReachability: curReach];

}

- (void) applicationDidFinishLaunching: (UIApplication* )application

{

    #pragma unused(application)

	contentView.backgroundColor = [UIColor groupTableViewBackgroundColor];

    summaryLabel.hidden = YES;        

    // Observe the kNetworkReachabilityChangedNotification. When that notification is posted, the

    // method "reachabilityChanged" will be called.

    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(reachabilityChanged:) name: kReachabilityChangedNotification object: nil];

    //Change the host name here to change the server your monitoring

    remoteHostLabel.text = [NSString stringWithFormat: @"Remote Host: %@", @"www.apple.com"];

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

	[hostReach startNotifier];

	[self updateInterfaceWithReachability: hostReach];

    internetReach = [[Reachability reachabilityForInternetConnection] retain];

	[internetReach startNotifier];

	[self updateInterfaceWithReachability: internetReach];

    wifiReach = [[Reachability reachabilityForLocalWiFi] retain];

	[wifiReach startNotifier];

	[self updateInterfaceWithReachability: wifiReach];

	[window makeKeyAndVisible];

}

@end

Reachability.zip