这个问题已经在这里有一个答案：
- 如何检查iOS和MacOS的活动的Internet连接？ 41个回答
这是检查使用了iOS SDK中的Internet连接的最佳方式？
Answer 1:
最好的办法是使用可达代码。 检查这里的苹果示例代码 。 这有很多方便的方法来检查网络可用性，WIFI /广域网连接检查等。
对于如： -
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkChanged:) name:kReachabilityChangedNotification object:nil];
reachability = [Reachability reachabilityForInternetConnection];
[reachability startNotifier];
- (void)networkChanged:(NSNotification *)notification
{
NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];
if(remoteHostStatus == NotReachable) { NSLog(@"not reachable");}
else if (remoteHostStatus == ReachableViaWiFiNetwork) { NSLog(@"wifi"); }
else if (remoteHostStatus == ReachableViaCarrierDataNetwork) { NSLog(@"carrier"); }
}
Answer 2:
可达性有很多更给它比它的需要，再加上它并没有被用于ARC还没有被更新。
这是我在纯C.解决大部分的代码是直接取自可达性，但蒸馏至只有什么是必要的。 我只是想它返回是否有或没有互联网连接，但你可以从评论是否它的返回是基于具有发现了一个Wi-Fi或蜂窝网络阅读。
之前在进行共享代码最后一点：你需要进入你的构建目标，选择构建阶段选项卡，“SystemConfiguration.framework”添加到“链接二进制与图书馆”名单。
#import <CoreFoundation/CoreFoundation.h>
#import <SystemConfiguration/SystemConfiguration.h>
#import <netdb.h>
BOOL networkReachable()
{
struct sockaddr_in zeroAddress;
bzero(&zeroAddress, sizeof(zeroAddress));
zeroAddress.sin_len = sizeof(zeroAddress);
zeroAddress.sin_family = AF_INET;
SCNetworkReachabilityRef reachabilityRef = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr *) &zeroAddress);
SCNetworkReachabilityFlags flags;
if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags)) {
if ((flags & kSCNetworkReachabilityFlagsReachable) == 0) {
// if target host is not reachable
return NO;
}
if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0) {
// if target host is reachable and no connection is required
// then we'll assume (for now) that your on Wi-Fi
return YES; // This is a wifi connection.
}
if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0)
||(flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0)) {
// ... and the connection is on-demand (or on-traffic) if the
// calling application is using the CFSocketStream or higher APIs
if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0) {
// ... and no [user] intervention is needed
return YES; // This is a wifi connection.
}
}
if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN) {
// ... but WWAN connections are OK if the calling application
// is using the CFNetwork (CFSocketStream?) APIs.
return YES; // This is a cellular connection.
}
}
return NO;
}
Answer 3:
试试这个代码：
- (BOOL)connectedToInternet
{
NSURL *url=[NSURL URLWithString:@"http://www.google.com"];
NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"HEAD"];
NSHTTPURLResponse *response;
[NSURLConnection sendSynchronousRequest:request returningResponse:&response error: NULL];
return ([response statusCode]==200)?YES:NO;
}
文章来源: Check for Internet connection using the iOS SDK [duplicate]
