直接上代码。。

////  ViewController.m//  Reachability检测联网状态////  Created by chen on 15/2/15.//  Copyright (c) 2015年 lanrw. All rights reserved.//#import "ViewController.h"#import "Reachability.h"@interface ViewController ()@property (nonatomic,strong) Reachability *myReachabity;@end@implementation ViewController- (Reachability *)myReachabity{    if(_myReachabity == nil){        _myReachabity = [Reachability reachabilityWithHostName:@"baidu.com"];    }    return _myReachabity;}- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.}- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{    switch ([self.myReachabity currentReachabilityStatus]) {        case NotReachable:            NSLog(@"没有联网");            break;        case ReachableViaWiFi:            NSLog(@"通过wifi联网");            break;        case ReachableViaWWAN:            NSLog(@"通过 2G/3G/4G联网");            break;    }}@end