iOS 判断网络状态 简单示例

添加SystemConfiguration.framework 到工程中

对应的.h文件

#import <UIKit/UIKit.h>@interface ViewController : UIViewController//如果方法前面加+，就相当于类的静态方法，这里要注意一下- (BOOL) connectedToNetwork;@end

对应的.m文件

#import "ViewController.h"#import <Foundation/Foundation.h>#import <CommonCrypto/CommonHMAC.h>#import <SystemConfiguration/SystemConfiguration.h>#import <netdb.h>#import <arpa/inet.h>@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    UIButton *btn = [[UIButton alloc]init];    btn.frame = CGRectMake(20, 20, 40, 40);    btn.backgroundColor = [UIColor brownColor];    [self.view addSubview:btn];    [btn addTarget:self action:@selector(testOut:) forControlEvents:UIControlEventTouchUpInside];    // Do any additional setup after loading the view, typically from a nib.}-(BOOL) connectedToNetwork{    // Create zero addy    struct sockaddr_in zeroAddress;    bzero(&zeroAddress, sizeof(zeroAddress));    zeroAddress.sin_len = sizeof(zeroAddress);    zeroAddress.sin_family = AF_INET;        // Recover reachability flags    SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);    SCNetworkReachabilityFlags flags;        BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);    CFRelease(defaultRouteReachability);        if (!didRetrieveFlags)        {        printf("Error. Could not recover network reachability flags\n");        return NO;        }        BOOL isReachable = ((flags & kSCNetworkFlagsReachable) != 0);    BOOL needsConnection = ((flags & kSCNetworkFlagsConnectionRequired) != 0);    return (isReachable && !needsConnection) ? YES : NO;}//在调用的时候，在对应的按钮中加入判断：- (IBAction)testOut:(UIButton *)sender{    if(![self connectedToNetwork])        {        UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"温馨提示" message:@"网络连接失败,请查看网络是否连接正常！" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];        [alert show];        }        NSLog(@"testOut Event");}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end