I am new to iOS and just started working on it. I am trying to implement network reachability to detect when the network is disconnected and when it gets back by using a third party class. I am able to detect the loss of network but I am not able to detect when the network gets back after it is disconnected. I am using the following condition for checking the disconnection which is working well :
// NSURLConnectionDelegate method: Handle the connection failing
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
Reachability *reachability = [Reachability reachabilityForInternetConnection];
[reachability startNotifier];
NetworkStatus internetStatus = [reachability currentReachabilityStatus];
if(internetStatus==NotReachable)
{
NSLog(#" Network Disconnected")
}
}
I have downloaded the third party reachability class from this link :https://github.com/tonymillion/Reachability
Can anyone suggest me the way to detect when the network is connected again?
You can simply place a notification in your class like this:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];
And then, you can use thiis method to observe when the network connection gets back i.e the connection state changes:
- (void) reachabilityChanged:(NSNotification *)note
{
Reachability* currentReach = [note object];
NSParameterAssert([currentReach isKindOfClass:[Reachability class]]);
if (internetStatus != NotReachable)
{
// handle UI as per your requirement
}
}
You called
[reachability startNotifier];
it means that each time reachabilty status is changed it will emit kReachabilityChangedNotification. So what you need now is to subscribe to receive this notification:
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(reachabilityStatusChanged:)
name:kReachabilityChangedNotification
object:nil];
and implement reachabilityStatusChanged: method:
- (void)reachabilityStatusChanged:(NSNotification *)notice {
Reachability *reachability = [Reachability reachabilityForInternetConnection];
NetworkStatus internetStatus = [reachability currentReachabilityStatus];
if (internetStatus != NotReachable)
{
// do what you need
}
}
Download Reachability.h from this:
https://developer.apple.com/Library/ios/samplecode/Reachability/Introduction/Intro.html
and subscribe to notification:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];
Related
I have downloaded Reachability Class from the developer's portal. On network change this is not working. Below is my code.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];
self.wifiReachability = [Reachability reachabilityForLocalWiFi];
[self.wifiReachability startNotifier];
[self updateInterfaceWithReachability:self.wifiReachability];
- (void) reachabilityChanged:(NSNotification *)note
{
Reachability* curReach = [note object];
NSParameterAssert([curReach isKindOfClass:[Reachability class]]);
[self updateInterfaceWithReachability:curReach];
}
Above notificaion is not calling on network change. Any suggestions?
I want my app to detect the internet connection loss automatically. So im using the following code.
- (void)applicationDidBecomeActive:(UIApplication *)application {
Reachability *networkReachability = [Reachability reachabilityForInternetConnection];
NetworkStatus networkStatus = [networkReachability currentReachabilityStatus];
if (networkStatus == NotReachable) {
[Settings hideSpinner];
//Show no internet connectivity dialog.
} else {
}
}
But the problem is that it is not checking the internet connectivity continually.
it checks only when the app has become active. How can I be able to check for internet connection continually throughout the app life cycle and throw an warning if internet goes off automatically?
Once your application has launched, you can fire a NSTimer to do the same:
- (void)applicationDidBecomeActive:(UIApplication *)application {
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0f
target:self
selector:#selector(checkForConnectivity)
userInfo:nil
repeats:YES];
}
-(void)checkForConnectivity {
Reachability *networkReachability = [Reachability reachabilityForInternetConnection];
NetworkStatus networkStatus = [networkReachability currentReachabilityStatus];
if (networkStatus == NotReachable) {
//No internet connectivity - perform required action
}
else {
//Internet connectivity is valid
}
}
Thanks!
Add obeserver like this in Reachability method.
1) [[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];
It will call automatically when your app open/in background mode and it call reachabilityChanged.
2) [[NSNotificationCenter defaultCenter] postNotificationName:#"ChangeInternetConnection" object:nil];
ChangeInternetConnection you have to add observer to your ViewController to get status when internet changing it's status.
- (void) checkInternetConnetion {
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil];
//NSString *remoteHostName = #"www.apple.com";
self.internetReachability = [Reachability reachabilityForInternetConnection];
[self.internetReachability startNotifier];
[self updateInterfaceWithReachability:self.internetReachability];
}
#pragma mark - Reachability Methods
- (void)updateInterfaceWithReachability:(Reachability *)reachability {
if (reachability == self.internetReachability) {
[self checkStatus:reachability];
}
if (reachability == self.wifiReachability) {
[self checkStatus:reachability];
}
}
-(void)checkStatus :(Reachability *)reachability {
NetworkStatus netStatus = [reachability currentReachabilityStatus];
BOOL connectionRequired = [reachability connectionRequired];
NSString* statusString = #"";
switch (netStatus) {
case NotReachable: {
self.isInternetOn = FALSE;
break;
}
case ReachableViaWWAN: {
self.isInternetOn = TRUE;
break;
}
case ReachableViaWiFi: {
self.isInternetOn = TRUE;
break;
}
}
[[NSNotificationCenter defaultCenter] postNotificationName:#"ChangeInternetConnection" object:nil];
}
- (void) reachabilityChanged:(NSNotification *)note {
Reachability* curReach = [note object];
NSParameterAssert([curReach isKindOfClass:[Reachability class]]);
[self updateInterfaceWithReachability:curReach];
}
Timer is not an efficient way to do this but you can also use timer too.
- (void)applicationDidBecomeActive:(UIApplication *)application
{
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0f
target:self
selector:#selector(handleConnectivity)
userInfo:nil
repeats:YES];
}
-(void)handleConnectivity
{
Reachability *networkReachability = [Reachability reachabilityForInternetConnection];
NetworkStatus networkStatus = [networkReachability currentReachabilityStatus];
if (networkStatus == NotReachable)
{
//No internet connectivity - perform required action
}
else
{
//Internet connectivity is valid
}
}
Best way is to use Reachability code. Check here for apple sample code. That has a lot of convenience methods to check internet availability, Wifi/WAN connectivity check etc..
For example:-
[[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"); }
}
You can only check this things in background
*audio—The app plays audible content to the user while in the background. (This content includes streaming audio or video content
using AirPlay.)
*location—The app keeps users informed of their location, even while it is running in the background.
*voip—The app provides the ability for the user to make phone calls using an Internet connection.
*newsstand-content—The app is a Newsstand app that downloads and processes magazine or newspaper content in the background.
*external-accessory—The app works with a hardware accessory that needs to deliver updates on a regular schedule through the External
Accessory framework.
*bluetooth-central—The app works with a Bluetooth accessory that needs to deliver updates on a regular schedule through the Core Bluetooth
framework.
*bluetooth-peripheral—The app supports Bluetooth communication in peripheral mode through the Core Bluetooth framework.
Firstly import in your class: #import "Reachability.h"
Then do like following way:
add an observer for reachability change notification
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(reachabilityChanged:)
name:kReachabilityChangedNotification object:nil];
-(BOOL)reachabilityChanged:(NSNotification*)note
{
BOOL status =YES;
NSLog(#"reachabilityChanged");
Reachability * reach = [note object];
if([reach isReachable])
{
status = YES;
NSLog(#"your network is Available");
}
else
{
status = NO;
//Do something here
}
return status;
}
Add a observer.
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(reachabilityChanged:)
name:kReachabilityChangedNotification
object:nil];
-(BOOL)reachabilityChanged:(NSNotification*)note
{
BOOL status =YES;
NSLog(#"reachability is changed");
Reachability * reach = [note object];
if([reach isReachable])
{
status = YES;
NSLog(#"NetWork is Available. Please go ahead");
}
else
{
status = NO;
NSLog(#"NetWork is not Available. Please check your connection.");
}
return status;
}
You can make use of Reachability framework from iOS and combine it with NSTimer.
I want to call a method when internet is active . But my method is call but it execute two time. I am unable how it is hapenning. Please help .Here is my code.
Reachability * reachability;
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(handleNetworkChanged:) name:kReachabilityChangedNotification object:nil];
- (void)applicationDidBecomeActive:(UIApplication *)application {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
[self handleNetworkChanged:nil];
}
- (BOOL)handleNetworkChanged:(NSNotification *) notice
{
reachability = [Reachability reachabilityForInternetConnection];
[reachability startNotifier];
NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];
if(remoteHostStatus == NotReachable) {
self.internetConnection = FALSE;
[[NSNotificationCenter defaultCenter] postNotificationName:#"NetworkGone" object:nil];
//NSLog(#"Internet is not Connected");
} else {
self.internetConnection = TRUE;
[[NSNotificationCenter defaultCenter] postNotificationName:#"NetworkCome" object:nil];
//NSLog(#"Internet is Connected");
}
return self.internetConnection;
}
Remove [self handleNetworkChanged:nil] from applicationDidBecomeActive.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(handleNetworkChanged:) name:kReachabilityChangedNotification object:nil];
- (void)applicationDidBecomeActive:(UIApplication *)application {
}
- (BOOL)handleNetworkChanged:(NSNotification *) notice
{
reachability = [Reachability reachabilityForInternetConnection];
[reachability startNotifier];
NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];
if(remoteHostStatus == NotReachable) {
self.internetConnection = FALSE;
[[NSNotificationCenter defaultCenter] postNotificationName:#"NetworkGone" object:nil];
//NSLog(#"Internet is not Connected");
} else {
self.internetConnection = TRUE;
[[NSNotificationCenter defaultCenter] postNotificationName:#"NetworkCome" object:nil];
//NSLog(#"Internet is Connected");
}
return self.internetConnection;
}
I've this scenario, UIViewController => UITableViewController => UITableViewController => UIViewController.
From first UITableViewController, I check internet connection and populate data based on that.
This is what the problem is -
1. At first UITableViewController wi-fi is on so data populated from URL,
2. I turn-off wi-fi and select row and go to second UITableViewController, network status is NotReachable and data is populated from database
3. I turn on wi-fi and select row and go to last UIViewcontroller, here network status is NotReachable whereas it should be ReachableViaWiFi
Am I missing something? Please suggest.
-(void) viewWillAppear:(BOOL)animated {
[[NSNotificationCenter defaultCenter] addObserver: self
selector: #selector(reachabilityChanged:)
name: kReachabilityChangedNotification
object: nil];
Reachability *reach = [Reachability reachabilityWithHostname: #"www.apple.com"];
[reach startNotifier];
}
- (void) reachabilityChanged: (NSNotification *)notification {
Reachability *reach = [notification object];
if( [reach isKindOfClass: [Reachability class]]) {
NetworkStatus status = [reach currentReachabilityStatus];
switch(status) {
case NotReachable:
{
if (!performedOnce) {
[self processOffline];
performedOnce = YES;
}
[[NSNotificationCenter defaultCenter] removeObserver:self name:kReachabilityChangedNotification object:nil];
}
break;
default:
{
if (!performedOnce) {
[self retrieveUserListWithUrl];
performedOnce = YES;
}
[[NSNotificationCenter defaultCenter] removeObserver:self name:kReachabilityChangedNotification object:nil];
}
break;
}
}
}
I want to trigger an action once the connection is available. There are solutions available which allows manually checking internet connection. One way i find is using NSTimer to check for internet connection during fixed intervals. But is it the most effective way to check for it? if Not, What is the right solution for this?
Here how you can register the observer and listen to it, Your application will be listening to kReachabilityChangedNotification & prompt you whenever status of network changes.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(reachabilityHasChanged:) name:kReachabilityChangedNotification object:nil];
internetReachable = [[Reachability reachabilityForInternetConnection] retain];
[internetReachable startNotifier];
-(void) reachabilityHasChanged:(NSNotification *)notice
{
// called after network status changes
NetworkStatus internetStatus = [internetReachable currentReachabilityStatus];
switch (internetStatus)
{
case NotReachable:
{
NSLog(#"The internet is down.");
break;
}
case ReachableViaWiFi:
{
NSLog(#"The internet is working via WIFI.");
break;
}
case ReachableViaWWAN:
{
NSLog(#"The internet is working via WWAN.");
break;
}
}
}
Check reachability code provided by apple.In appdelegate.m you can see this method.It will notify the network change.Work on it
//Called by Reachability whenever status changes.
- (void) reachabilityChanged: (NSNotification* )note
{
Reachability* curReach = [note object];
NSParameterAssert([curReach isKindOfClass: [Reachability class]]);
[self updateInterfaceWithReachability: curReach];
}