iOS检测网络连接状态

官方Demo下载地址：https://developer.apple.com/library/ios/samplecode/Reachability/Reachability.zip

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。

下面代码：

//
//  ViewController.m
//  网络状态监测
//
//  Created by 王卫亮 on 15/2/4.
//  Copyright © 2015年 王卫亮. All rights reserved.
//

#import "ViewController.h"
#import "Reachability.h"
#import <ifaddrs.h>

@interface ViewController ()
@property (nonatomic, strong)Reachability *conn;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // 设置网络状态变化时的通知函数
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkStateChange) name:kReachabilityChangedNotification object:nil];

    self.conn = [Reachability reachabilityForInternetConnection];
    [self.conn startNotifier];//开始监测
}

-(void)dealloc{
    [self.conn stopNotifier];//停止监测
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void)networkStateChange{
    [self checkNetworkState];
}

//检测网络状态
- (void)checkNetworkState{
    // 1.检测wifi状态
    Reachability *wifi = [Reachability reachabilityForLocalWiFi];

    // 2.检测手机是否能上网络(WIFI\3G\2.5G)
    Reachability *conn = [Reachability reachabilityForInternetConnection];

    // 3.判断网络状态
    if ([wifi currentReachabilityStatus] != NotReachable) { // 有wifi
        NSLog(@"有wifi");
    } else if ([conn currentReachabilityStatus] != NotReachable) { // 没有使用wifi, 使用手机自带网络进行上网
        NSLog(@"使用手机自带网络进行上网");
    } else { // 没有网络
        NSLog(@"没有网络");
    }
}

//如果只是判断是否有网，可以返回BOOL值

- (BOOL)checkNetwork{
    // 1.检测wifi状态
    Reachability *wifi = [Reachability reachabilityForLocalWiFi];

    // 2.检测手机是否能上网络(WIFI\3G\2.5G)
    Reachability *conn = [Reachability reachabilityForInternetConnection];

    // 3.判断网络状态
    if ([wifi currentReachabilityStatus] != NotReachable || [conn currentReachabilityStatus] != NotReachable) {
        return YES;
    } else { // 没有网络
        return NO;
    }
}

//需要导入ifadds头文件

//是否连接VPN

- (BOOL)isVPNConnected{
    struct ifaddrs *interfaces = NULL;
    struct ifaddrs *temp_addr = NULL;
    int success = ;
    //检索当前接口，0 成功
    success = getifaddrs(&interfaces);
    if (success == ) {
        //循环链表接口
        temp_addr = interfaces;
        while (temp_addr != NULL) {
            NSString *string = [NSString stringWithFormat:@"%s" , temp_addr->ifa_name];
            if ([string rangeOfString:@"tap"].location != NSNotFound ||
                [string rangeOfString:@"tun"].location != NSNotFound ||
                [string rangeOfString:@"ppp"].location != NSNotFound){
                return YES;
            }
            temp_addr = temp_addr->ifa_next;
        }
    }
    // Free memory
    freeifaddrs(interfaces);
    return NO;
}

@end

很多公司的项目中都使用了AFNetworking, 或者封装了AFNetworking的YTKNetworking ，AFNetworking封装有Reachability的网络监测，可以直接拿来用

#pragma 监测网络的可链接性
+ (BOOL)netWorkReachabilityWithURLString:(NSString *) strUrl {
    __block BOOL netState = NO;
    NSURL *baseURL = [NSURL URLWithString:strUrl];
    AFHTTPRequestOperationManager *manager = [[AFHTTPRequestOperationManager alloc] initWithBaseURL:baseURL];
    NSOperationQueue *operationQueue = manager.operationQueue;
    [manager.reachabilityManager setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
        switch (status) {
            case AFNetworkReachabilityStatusReachableViaWWAN:
            case AFNetworkReachabilityStatusReachableViaWiFi:
                [operationQueue setSuspended:NO];
                netState = YES;
                break;
            case AFNetworkReachabilityStatusNotReachable:
                netState = NO;
            default:
                [operationQueue setSuspended:YES];
                break;
        }
    }];

    [manager.reachabilityManager startMonitoring];
    return netState;
}