I would like to check to see if I have an Internet connection on iOS using the Cocoa Touch libraries or on macOS using the Cocoa libraries.
I came up with a way to do this using an NSURL
. The way I did it seems a bit unreliable (because even Google could one day be down and relying on a third party seems bad), and while I could check to see for a response from some other websites if Google didn’t respond, it does seem wasteful and an unnecessary overhead on my application.
- (BOOL) connectedToInternet
{
NSString *URLString = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];
return ( URLString != NULL ) ? YES : NO;
}
Is what I have done bad, (not to mention stringWithContentsOfURL
is deprecated in iOS 3.0 and macOS 10.4) and if so, what is a better way to accomplish this?
9
46 Answers
Important: This check should always be performed asynchronously. The majority of answers below are synchronous so be careful otherwise you’ll freeze up your app.
Swift
Install via CocoaPods or Carthage: https://github.com/ashleymills/Reachability.swift
Test reachability via closures
let reachability = Reachability()! reachability.whenReachable = { reachability in if reachability.connection == .wifi { print("Reachable via WiFi") } else { print("Reachable via Cellular") } } reachability.whenUnreachable = { _ in print("Not reachable") } do { try reachability.startNotifier() } catch { print("Unable to start notifier") }
Objective-C
Add
SystemConfiguration
framework to the project but don’t worry about including it anywhereAdd Tony Million’s version of
Reachability.h
andReachability.m
to the project (found here: https://github.com/tonymillion/Reachability)Update the interface section
#import "Reachability.h" // Add this to the interface in the .m file of your view controller @interface MyViewController () { Reachability *internetReachableFoo; } @end
Then implement this method in the .m file of your view controller which you can call
// Checks if we have an internet connection or not - (void)testInternetConnection { internetReachableFoo = [Reachability reachabilityWithHostname:@"www.google.com"]; // Internet is reachable internetReachableFoo.reachableBlock = ^(Reachability*reach) { // Update the UI on the main thread dispatch_async(dispatch_get_main_queue(), ^{ NSLog(@"Yayyy, we have the interwebs!"); }); }; // Internet is not reachable internetReachableFoo.unreachableBlock = ^(Reachability*reach) { // Update the UI on the main thread dispatch_async(dispatch_get_main_queue(), ^{ NSLog(@"Someone broke the internet :("); }); }; [internetReachableFoo startNotifier]; }
Important Note: The Reachability
class is one of the most used classes in projects so you might run into naming conflicts with other projects. If this happens, you’ll have to rename one of the pairs of Reachability.h
and Reachability.m
files to something else to resolve the issue.
Note: The domain you use doesn’t matter. It’s just testing for a gateway to any domain.
38
@gonzobrains: The domain you use doesn’t matter. It’s just testing for a gateway to any domain.
@KaanDedeoglu It’s just an example, use whatever domain you want. It simply checks for a gateway to the internet, not that the domain is actually available.
Oh, btw you need to add
SystemConfiguration.framework
to the project as well (for method 1).– wiseindyUse http://www.appleiphonecell.com instead of google.com – this url was created by apple for precisely this reason.
– Smikey@iWasRobbed – ty. I found a blog post that spells out exactly what you’re talking about: code.tutsplus.com/tutorials/…
I like to keep things simple. The way I do this is:
//Class.h
#import "Reachability.h"
#import <SystemConfiguration/SystemConfiguration.h>
- (BOOL)connected;
//Class.m
- (BOOL)connected
{
Reachability *reachability = [Reachability reachabilityForInternetConnection];
NetworkStatus networkStatus = [reachability currentReachabilityStatus];
return networkStatus != NotReachable;
}
Then, I use this whenever I want to see if I have a connection:
if (![self connected]) {
// Not connected
} else {
// Connected. Do some Internet stuff
}
This method doesn’t wait for changed network statuses in order to do stuff. It just tests the status when you ask it to.
3
Hi @msec, you can try Andrew Zimmer solution in this page, it works fine with adsl disconnected (and wifi connected)
– WilliewFor those who just copy and paste like i did with the above code. Also add SystemConfiguration.framework manually or you will get linking error.
Always come as reachable if i connect with WiFi. WiFi doesn’t mean that it is having internet connection. I wanna verify internet connection even it has WiFi connectivity. Can you please help me out?
– wesley
Using Apple’s Reachability code, I created a function that’ll check this correctly without you having to include any classes.
Include the SystemConfiguration.framework in your project.
Make some imports:
#import <sys/socket.h>
#import <netinet/in.h>
#import <SystemConfiguration/SystemConfiguration.h>
Now just call this function:
/*
Connectivity testing code pulled from Apple's Reachability Example: https://developer.apple.com/library/content/samplecode/Reachability
*/
+(BOOL)hasConnectivity {
struct sockaddr_in zeroAddress;
bzero(&zeroAddress, sizeof(zeroAddress));
zeroAddress.sin_len = sizeof(zeroAddress);
zeroAddress.sin_family = AF_INET;
SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)&zeroAddress);
if (reachability != NULL) {
//NetworkStatus retVal = NotReachable;
SCNetworkReachabilityFlags flags;
if (SCNetworkReachabilityGetFlags(reachability, &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;
}
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;
}
}
if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
{
// ... but WWAN connections are OK if the calling application
// is using the CFNetwork (CFSocketStream?) APIs.
return YES;
}
}
}
return NO;
}
And it’s iOS 5 tested for you.
6
@JezenThomas This doesn’t perform the internet check asynchronously, which is why it is “much slimmer”… You should always be doing this asynchronously by subscribing to notifications so that you don’t hang up the app on this process.
Thanks, this work even if you are using wifi adsl and adsl is not connected, is exactly what I need.
– WilliewThis leaks memory – the ‘readability’ structure (object, thing) needs to be freed with CFRelease().
Weird that this answer predates mine (on a question marked as a duplicate) by 2 years, is exactly the same as mine, but I never saw it until today.
This used to be the correct answer, but it is now outdated as you should subscribe to notifications for reachability instead. This method checks synchronously:
You can use Apple’s Reachability class. It will also allow you to check if Wi-Fi is enabled:
Reachability* reachability = [Reachability sharedReachability];
[reachability setHostName:@"www.example.com"]; // Set your host name here
NetworkStatus remoteHostStatus = [reachability remoteHostStatus];
if (remoteHostStatus == NotReachable) { }
else if (remoteHostStatus == ReachableViaWiFiNetwork) { }
else if (remoteHostStatus == ReachableViaCarrierDataNetwork) { }
The Reachability class is not shipped with the SDK, but rather a part of this Apple sample application. Just download it, and copy Reachability.h/m to your project. Also, you have to add the SystemConfiguration framework to your project.
2
See my comment above about not using Reachability like that. Use it in asynchronous mode and subscribe to the notifications it sends – don’t.
This code is a good starting point for things that you need to set before you can use the delegate methods for the reachability class.
–
Here’s a very simple answer:
NSURL *scriptUrl = [NSURL URLWithString:@"http://www.google.com/m"];
NSData *data = [NSData dataWithContentsOfURL:scriptUrl];
if (data)
NSLog(@"Device is connected to the Internet");
else
NSLog(@"Device is not connected to the Internet");
The URL should point to an extremely small website. I use Google’s mobile website here, but if I had a reliable web server I’d upload a small file with just one character in it for maximum speed.
If checking whether the device is somehow connected to the Internet is everything you want to do, I’d definitely recommend using this simple solution. If you need to know how the user is connected, using Reachability is the way to go.
Careful: This will briefly block your thread while it loads the website. In my case, this wasn’t a problem, but you should consider this (credits to Brad for pointing this out).
9
I really like this idea, but I would say for the 99.999% reliability while maintaining a small response size, go with http://www.google.com/m which is the mobile view for google.
– rwylandAwesome solution @Erik. What i also recommend you is to use http://www.google.com, instead of http://www.google.com/m, as rwyland said. It’s weird, but from my test the mobile version always takes about 120ms more than the http://www.google.com
– SebydddApple docs recommend not to do this since it can block the thread on a slow network, can cause app to be terminated in iOS
Thanks for the positive feedback, agree that http://www.google.com/m is the best solution because of reliability!
– ErikLOL, I’m sure Google appreciate you suggesting people use them as an Internet check resource.
– mxcl
Here is how I do it in my apps: While a 200 status response code doesn’t guarantee anything, it is stable enough for me. This doesn’t require as much loading as the NSData answers posted here, as mine just checks the HEAD response.
Swift Code
func checkInternet(flag:Bool, completionHandler:(internet:Bool) -> Void)
{
UIApplication.sharedApplication().networkActivityIndicatorVisible = true
let url = NSURL(string: "http://www.google.com/")
let request = NSMutableURLRequest(URL: url!)
request.HTTPMethod = "HEAD"
request.cachePolicy = NSURLRequestCachePolicy.ReloadIgnoringLocalAndRemoteCacheData
request.timeoutInterval = 10.0
NSURLConnection.sendAsynchronousRequest(request, queue:NSOperationQueue.mainQueue(), completionHandler:
{(response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in
UIApplication.sharedApplication().networkActivityIndicatorVisible = false
let rsp = response as! NSHTTPURLResponse?
completionHandler(internet:rsp?.statusCode == 200)
})
}
func yourMethod()
{
self.checkInternet(false, completionHandler:
{(internet:Bool) -> Void in
if (internet)
{
// "Internet" aka Google URL reachable
}
else
{
// No "Internet" aka Google URL un-reachable
}
})
}
Objective-C Code
typedef void(^connection)(BOOL);
- (void)checkInternet:(connection)block
{
NSURL *url = [NSURL URLWithString:@"http://www.google.com/"];
NSMutableURLRequest *headRequest = [NSMutableURLRequest requestWithURL:url];
headRequest.HTTPMethod = @"HEAD";
NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration ephemeralSessionConfiguration];
defaultConfigObject.timeoutIntervalForResource = 10.0;
defaultConfigObject.requestCachePolicy = NSURLRequestReloadIgnoringLocalAndRemoteCacheData;
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration:defaultConfigObject delegate:self delegateQueue: [NSOperationQueue mainQueue]];
NSURLSessionDataTask *dataTask = [defaultSession dataTaskWithRequest:headRequest
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error)
{
if (!error && response)
{
block([(NSHTTPURLResponse *)response statusCode] == 200);
}
}];
[dataTask resume];
}
- (void)yourMethod
{
[self checkInternet:^(BOOL internet)
{
if (internet)
{
// "Internet" aka Google URL reachable
}
else
{
// No "Internet" aka Google URL un-reachable
}
}];
}
14
Seems like this is the fastest way
– PavelCaution: In my experience, this solution doesn’t work all the time. In many cases the response returned is 403, after taking its sweet time. This solution seemed perfect, but doesn’t guarantee 100% results.
– MustafaAs of June 2014, this will fail in mainland China, owing to the Chinese government now completely blocking google.com. (google.cn works, though, but in mainland China, no baidu.com, no internet) Probably better to ping whatever server you need to be communicating with.
– prewettUse http://www.appleiphonecell.com instead – apple created this url for precisely this reason.
– SmikeyI used appleiphonecell as it is Apple’s own, can be used in China as well, and it’s a very fast website. This, in conjunction with your answer provided me with the nearest and fastest solution. Thank you
Apple supplies sample code to check for different types of network availability. Alternatively there is an example in the iPhone developers cookbook.
Note: Please see @KHG’s comment on this answer regarding the use of Apple’s reachability code.
3
Thanks. I discovered that the Xcode documentation in 3.0 also contains the source code, found by searching for “reachability” in the documentation.
–Note that the new revision (09-08-09) of the Reachability sample code from Apple is asynchronous.
The links are dead
You could use Reachability
by (available here).
#import "Reachability.h"
- (BOOL)networkConnection {
return [[Reachability reachabilityWithHostName:@"www.google.com"] currentReachabilityStatus];
}
if ([self networkConnection] == NotReachable) { /* No Network */ } else { /* Network */ } //Use ReachableViaWiFi / ReachableViaWWAN to get the type of connection.
1
@Supertecnoboff No, it’s async.
Apple provides a sample app which does exactly this:
4
You should note that the Reachability sample only detects which interfaces are active, but not which ones have a valid connection to the internet. Applications should gracefully handle failure even when Reachability reports that everything is ready to go.
– rpetrichHappily the situation is a lot better in 3.0, as the system will present a login page for users behind a locked down WiFi where you have to login to use… you use to have to check for the redirect manually (and you still do if developing 2.2.1 apps)
I wouldn’t say that the Reachability app does exactly what the is asked for. However it’s a good starting point for adding the kind of functionality that is asked for,
Broken link!, would appreciate if this can be checked/fixed, many thanks
Only the Reachability class has been updated. You can now use:
Reachability* reachability = [Reachability reachabilityWithHostName:@"www.apple.com"];
NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];
if (remoteHostStatus == NotReachable) { NSLog(@"not reachable");}
else if (remoteHostStatus == ReachableViaWWAN) { NSLog(@"reachable via wwan");}
else if (remoteHostStatus == ReachableViaWiFi) { NSLog(@"reachable via wifi");}
2
Unless something changed since 4.0 was released, that code is not asynchronous and you are guaranteed to see it show up in Crash Reports – happened to me before.
– bpapaI agree with bpapa. It’s not a good idea to use synchronous code. Thanks for the info though
–
If you’re using AFNetworking
you can use its own implementation for internet reachability status.
The best way to use AFNetworking
is to subclass the AFHTTPClient
class and use this class to do your network connections.
One of the advantages of using this approach is that you can use blocks
to set the desired behavior when the reachability status changes. Supposing that I’ve created a singleton subclass of AFHTTPClient
(as said on the “Subclassing notes” on AFNetworking docs) named BKHTTPClient
, I’d do something like:
BKHTTPClient *httpClient = [BKHTTPClient sharedClient];
[httpClient setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status)
{
if (status == AFNetworkReachabilityStatusNotReachable)
{
// Not reachable
}
else
{
// Reachable
}
}];
You could also check for Wi-Fi or WLAN connections specifically using the AFNetworkReachabilityStatusReachableViaWWAN
and AFNetworkReachabilityStatusReachableViaWiFi
enums (more here).
0
I’ve used the code in this discussion, and it seems to work fine (read the whole thread!).
I haven’t tested it exhaustively with every conceivable kind of connection (like ad hoc Wi-Fi).
1
this code is not totally good because it just checks to see if you have wifi connection with a router, not if the web can be reached. You can have wifi working and continue enable to reach the web.
– Duck
Very simple…. Try these steps:
Step 1: Add the SystemConfiguration
framework into your project.
Step 2: Import the following code into your header
file.
#import <SystemConfiguration/SystemConfiguration.h>
Step 3: Use the following method
Type 1:
- (BOOL) currentNetworkStatus { [UIApplication sharedApplication].networkActivityIndicatorVisible = NO; BOOL connected; BOOL isConnected; const char *host = "www.apple.com"; SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithName(NULL, host); SCNetworkReachabilityFlags flags; connected = SCNetworkReachabilityGetFlags(reachability, &flags); isConnected = NO; isConnected = connected && (flags & kSCNetworkFlagsReachable) && !(flags & kSCNetworkFlagsConnectionRequired); CFRelease(reachability); return isConnected; }
Type 2:
Import header :
#import "Reachability.h"
- (BOOL)currentNetworkStatus { Reachability *reachability = [Reachability reachabilityForInternetConnection]; NetworkStatus networkStatus = [reachability currentReachabilityStatus]; return networkStatus != NotReachable; }
Step 4: How to use:
- (void)CheckInternet
{
BOOL network = [self currentNetworkStatus];
if (network)
{
NSLog(@"Network Available");
}
else
{
NSLog(@"No Network Available");
}
}
2
Is type 1 asynchronous?
I want the type 2 fixes from your answer. I have added the reachability classes and i tried to check the connection verification by using above your answer. it always comes reachable even if i connect with WiFi but it doesn’t have the internet connection. WiFi doesn’t mean that it is having internet connection. I wanna verify internet connection even it has WiFi connectivity. Can you please help me out?
– wesley
When using iOS 12 or macOS v10.14 (Mojave) or newer, you can use NWPathMonitor
instead of the pre-historic Reachability
class. As a bonus you can easily detect the current network connection type:
import Network // Put this on top of your class
let monitor = NWPathMonitor()
monitor.pathUpdateHandler = { path in
if path.status != .satisfied {
// Not connected
}
else if path.usesInterfaceType(.cellular) {
// Cellular 3/4/5g connection
}
else if path.usesInterfaceType(.wifi) {
// Wi-Fi connection
}
else if path.usesInterfaceType(.wiredEthernet) {
// Ethernet connection
}
}
monitor.start(queue: DispatchQueue.global(qos: .background))
More info here: https://developer.apple.com/documentation/network/nwpathmonitor
-(void)newtworkType {
NSArray *subviews = [[[[UIApplication sharedApplication] valueForKey:@"statusBar"] valueForKey:@"foregroundView"]subviews];
NSNumber *dataNetworkItemView = nil;
for (id subview in subviews) {
if([subview isKindOfClass:[NSClassFromString(@"UIStatusBarDataNetworkItemView") class]]) {
dataNetworkItemView = subview;
break;
}
}
switch ([[dataNetworkItemView valueForKey:@"dataNetworkType"]integerValue]) {
case 0:
NSLog(@"No wifi or cellular");
break;
case 1:
NSLog(@"2G");
break;
case 2:
NSLog(@"3G");
break;
case 3:
NSLog(@"4G");
break;
case 4:
NSLog(@"LTE");
break;
case 5:
NSLog(@"Wifi");
break;
default:
break;
}
}
2
Even if the device is connected to Wifi or some other network type, the internet connection can still be unavailable. Simple test: connect to your home wifi and then unplug your cable modem. Still connected to wifi, but zero internet.
An explanation would be in order. E.g., what is the idea/gist? Please respond by editing (changing) your answer, not here in comments (without “Edit:”, “Update:”, or similar – the answer should appear as if it was written today).
- (void)viewWillAppear:(BOOL)animated
{
NSString *URL = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];
return (URL != NULL ) ? YES : NO;
}
Or use the Reachability class.
There are two ways to check Internet availability using the iPhone SDK:
1. Check the Google page is opened or not.
2. Reachability Class
For more information, please refer to Reachability (Apple Developer).
2
There are two way to check internet availbility in iPhone SDK 1)Check the Google page is opened or not.
-1 : This is a synchronous method that will block the main thread (the one that the app UI is changed on) while it tries to connect to google.com. If your user is on a very slow data connection, the phone will act like the process is unresponsive.
First: Add CFNetwork.framework
in framework
Code: ViewController.m
#import "Reachability.h"
- (void)viewWillAppear:(BOOL)animated
{
Reachability *r = [Reachability reachabilityWithHostName:@"www.google.com"];
NetworkStatus internetStatus = [r currentReachabilityStatus];
if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN))
{
/// Create an alert if connection doesn't work
UIAlertView *myAlert = [[UIAlertView alloc]initWithTitle:@"No Internet Connection" message:NSLocalizedString(@"InternetMessage", nil)delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
[myAlert show];
[myAlert release];
}
else
{
NSLog(@"INTERNET IS CONNECT");
}
}
First download the reachability class and put reachability.h and reachabilty.m file in your Xcode.
The best way is to make a common Functions class (NSObject) so that you can use it any class. These are two methods for a network connection reachability check:
+(BOOL) reachabiltyCheck
{
NSLog(@"reachabiltyCheck");
BOOL status =YES;
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(reachabilityChanged:)
name:kReachabilityChangedNotification
object:nil];
Reachability * reach = [Reachability reachabilityForInternetConnection];
NSLog(@"status : %d",[reach currentReachabilityStatus]);
if([reach currentReachabilityStatus]==0)
{
status = NO;
NSLog(@"network not connected");
}
reach.reachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
});
};
reach.unreachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
});
};
[reach startNotifier];
return status;
}
+(BOOL)reachabilityChanged:(NSNotification*)note
{
BOOL status =YES;
NSLog(@"reachabilityChanged");
Reachability * reach = [note object];
NetworkStatus netStatus = [reach currentReachabilityStatus];
switch (netStatus)
{
case NotReachable:
{
status = NO;
NSLog(@"Not Reachable");
}
break;
default:
{
if (!isSyncingReportPulseFlag)
{
status = YES;
isSyncingReportPulseFlag = TRUE;
[DatabaseHandler checkForFailedReportStatusAndReSync];
}
}
break;
}
return status;
}
+ (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)
{
NSLog(@"Error. Could not recover network reachability flags");
return NO;
}
BOOL isReachable = flags & kSCNetworkFlagsReachable;
BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
BOOL nonWiFi = flags & kSCNetworkReachabilityFlagsTransientConnection;
NSURL *testURL = [NSURL URLWithString:@"http://www.apple.com/"];
NSURLRequest *testRequest = [NSURLRequest requestWithURL:testURL cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:20.0];
NSURLConnection *testConnection = [[NSURLConnection alloc] initWithRequest:testRequest delegate:self];
return ((isReachable && !needsConnection) || nonWiFi) ? (testConnection ? YES : NO) : NO;
}
Now you can check network connection in any class by calling this class method.
There is also another method to check Internet connection using the iPhone SDK.
Try to implement the following code for the network connection.
#import <SystemConfiguration/SystemConfiguration.h>
#include <netdb.h>
/**
Checking for network availability. It returns
YES if the network is available.
*/
+ (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 flagsn");
return NO;
}
BOOL isReachable = ((flags & kSCNetworkFlagsReachable) != 0);
BOOL needsConnection = ((flags & kSCNetworkFlagsConnectionRequired) != 0);
return (isReachable && !needsConnection) ? YES : NO;
}
I found it simple and easy to use library SimplePingHelper.
Sample code: chrishulbert/SimplePingHelper (GitHub)
Download the Reachability file, https://gist.github.com/darkseed/1182373
And add
CFNetwork.framework
and ‘SystemConfiguration.framework’ in frameworkDo #import “Reachability.h”
First: Add CFNetwork.framework
in framework
Code: ViewController.m
- (void)viewWillAppear:(BOOL)animated
{
Reachability *r = [Reachability reachabilityWithHostName:@"www.google.com"];
NetworkStatus internetStatus = [r currentReachabilityStatus];
if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN))
{
/// Create an alert if connection doesn't work
UIAlertView *myAlert = [[UIAlertView alloc]initWithTitle:@"No Internet Connection" message:NSLocalizedString(@"InternetMessage", nil)delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
[myAlert show];
[myAlert release];
}
else
{
NSLog(@"INTERNET IS CONNECT");
}
}
Swift 3 / Swift 4
You must first import
import SystemConfiguration
You can check the Internet connection with the following method:
func isConnectedToNetwork() -> Bool {
var zeroAddress = sockaddr_in()
zeroAddress.sin_len = UInt8(MemoryLayout.size(ofValue: zeroAddress))
zeroAddress.sin_family = sa_family_t(AF_INET)
let defaultRouteReachability = withUnsafePointer(to: &zeroAddress) {
$0.withMemoryRebound(to: sockaddr.self, capacity: 1) {zeroSockAddress in
SCNetworkReachabilityCreateWithAddress(nil, zeroSockAddress)
}
}
var flags = SCNetworkReachabilityFlags()
if !SCNetworkReachabilityGetFlags(defaultRouteReachability!, &flags) {
return false
}
let isReachable = (flags.rawValue & UInt32(kSCNetworkFlagsReachable)) != 0
let needsConnection = (flags.rawValue & UInt32(kSCNetworkFlagsConnectionRequired)) != 0
return (isReachable && !needsConnection)
}
0
The Reachability class is OK to find out if the Internet connection is available to a device or not…
But in case of accessing an intranet resource:
Pinging the intranet server with the reachability class always returns true.
So a quick solution in this scenario would be to create a web method called pingme
along with other webmethods on the service.
The pingme
should return something.
So I wrote the following method on common functions
-(BOOL)PingServiceServer
{
NSURL *url=[NSURL URLWithString:@"http://www.serveraddress/service.asmx/Ping"];
NSMutableURLRequest *urlReq=[NSMutableURLRequest requestWithURL:url];
[urlReq setTimeoutInterval:10];
NSURLResponse *response;
NSError *error = nil;
NSData *receivedData = [NSURLConnection sendSynchronousRequest:urlReq
returningResponse:&response
error:&error];
NSLog(@"receivedData:%@",receivedData);
if (receivedData !=nil)
{
return YES;
}
else
{
NSLog(@"Data is null");
return NO;
}
}
The above method was so useful for me, so whenever I try to send some data to the server I always check the reachability of my intranet resource using this low timeout URLRequest.
To do this yourself is extremely simple. The following method will work. Just be sure to not allow a hostname protocol such as HTTP, HTTPS, etc. to be passed in with the name.
-(BOOL)hasInternetConnection:(NSString*)urlAddress
{
SCNetworkReachabilityRef ref = SCNetworkReachabilityCreateWithName(kCFAllocatorDefault, [urlAddress UTF8String]);
SCNetworkReachabilityFlags flags;
if (!SCNetworkReachabilityGetFlags(ref, &flags))
{
return NO;
}
return flags & kSCNetworkReachabilityFlagsReachable;
}
It is quick simple and painless.
Apart from reachability you may also use the Simple Ping helper library. It works really nice and is simple to integrate.
I think this one is the best answer.
“Yes” means connected. “No” means disconnected.
#import "Reachability.h"
- (BOOL)canAccessInternet
{
Reachability *IsReachable = [Reachability reachabilityForInternetConnection];
NetworkStatus internetStats = [IsReachable currentReachabilityStatus];
if (internetStats == NotReachable)
{
return NO;
}
else
{
return YES;
}
}
- Step 1: Add the Reachability class in your Project.
- Step 2: Import the Reachability class
Step 3: Create the below function
- (BOOL)checkNetConnection { self.internetReachability = [Reachability reachabilityForInternetConnection]; [self.internetReachability startNotifier]; NetworkStatus netStatus = [self.internetReachability currentReachabilityStatus]; switch (netStatus) { case NotReachable: { return NO; } case ReachableViaWWAN: { return YES; } case ReachableViaWiFi: { return YES; } } }
Step 4: Call the function as below:
if (![self checkNetConnection]) { [GlobalFunctions showAlert:@"" message:@"Please connect to the Internet!" canBtntitle:nil otherBtnTitle:@"Ok"]; return; } else { Log.v("internet is connected","ok"); }
1
Apple’s docs state this Note: Reachability cannot tell your application if you can connect to a particular host, only that an interface is available that might allow a connection, and whether that interface is the WWAN.
Rather
return (BOOL)URLString;
, or even better,return !!URLString
orreturn URLString != nil
I don’t know what your use case is, but if you can it’s preferable to try the request and handle any errors such as a lack of connection that arise. If you can’t do this, then there’s plenty of good advice here in this case.
Your solution is clever, and I prefer it. You can also use
NSString *URLString = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"https://twitter.com/getibox"] encoding:NSUTF8StringEncoding error:nil];
To get rid of the annoying warning.try using Reachability class from the below link, it will work for you github.com/tonymillion/Reachability
For those recently finding this answer: stackoverflow.com/a/8813279