In my iPhone app, I need to detect the internet Connection availability.
So I am referencing some files from "Reachability" project of Apple.
Link is given below:
http://developer.apple.com/library/ios/#samplecode/Reachability/Introduction/Intro.html
I create a new project and implement the code below in viewWillAppear but the app crashes.
I included the Reachability.h, Reachability.m from Apple's demo project.
I also included SystemConfiguration Framework.
app works fine when Internet is Working. But app Crashes when Internet in not Working.
Even I checked the console but there is no notification or error shown in the console.
Reachability *r = [Reachability reachabilityWithHostName:#"www.google.com"];
NetworkStatus internetStatus = [r currentReachabilityStatus];
if ((internetStatus == ReachableViaWiFi) || (internetStatus == ReachableViaWWAN))
{
UIAlertView *myAlert = [[UIAlertView alloc] initWithTitle:#"Internet Connection" message:#"Available" delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil];
[myAlert show];
[myAlert release];
}
else
{
UIAlertView *myAlert = [[UIAlertView alloc] initWithTitle:#"No Internet Connection" message:#"This app require an internet connection via WiFi or cellular network to work." delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil];
[myAlert show];
[myAlert release];
}
What could be the reason for crash?
What should I do?
Thanks!!
You're over-releasing the alerts. First, you do autorelease and then additionally release, which is too much. Just remove the two [myAlert release]; and it should work.
Here it may be the case that your code does not work on simulator because of time out. But try running it on device. Also try debugging the code as #greg rightly said. For that credit should go to #greg. Hope this helps. Let me know if it works.
Your problem is elsewhere in your code, as the code you provided along with copying Reachability.[mh] into a fresh Xcode project seems to work without crashing. When your app crashes, it must have some sort of information logged in the console. If there truly is nothing, set a breakpoint in your "startup" methods (viewWillLoad, viewDidLoad, AppDelegate stuff and step through line-by-line until you catch the problem.
Related
I'm in the process of submitting my app to the App Store, but I read that I must notify the user if the internet connection is down when my app needs it. The Apple page mentioned Reachability as well. Currently, though, I'm using the UIWebView delegate method didFailLoadWithError...
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
UIAlertView *errorAlert = [[UIAlertView alloc] initWithTitle:#"Error Loading" message:[error localizedDescription] delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[errorAlert show];
}
...and it's working fine. My question is, will my app be rejected for not using Reachability to do this, or is it fine doing what I am currently doing?
Thanks in advance.
No, you're perfectly ok using didFailLoadWithError:.
Reachability class could be used to check if host is up (or internet connection at all) before even trying to load some page. But it is not neccessery, as long as you handle the possible errors - which obviously you do.
EDIT:
It is still a good practice to know wheather you will be able to reach a certain host or not. You could even modify GUI for each case (instead of just reporting an error). But this can always be done in update :)
I am new to iphone..
Actually i wanted to know is it possible to put an UIAlertView after the completion of NSLog as i wanted to check whether the statement really works or not as i cant check NSLog in the iphone.
Please suggest me whether it is possible and how?
NSLog will still work on iPhone..
You can only see it in the console if you have attached the device to your mac..and then use the app.
Anyways.
You can show your AlertView after log like this.( This Nslog is an example..replace with what is your actual log)
NSLog(#" Image Loaded");
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Log" message:#"Image Loaded" delegate:nil cancelButtonTitle:#"Okay" otherButtonTitles:nil, nil];
[alert show];
[alert release];
If the NSLog statement works, it'll show up in the XCode console. So if you debug the app on your phone via XCode, you should see the NSLog. Or did you have something else on your mind ?
I have a code to detect if I have internet connection or not, and sometimes it doesn't work well. Here's the code:
-(void) webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
UIAlertView *alert= [[UIAlertView alloc] initWithTitle:#"Error" message:#"Couldn't connect to the Internet. Please check your connection." delegate:self cancelButtonTitle:#"OK" otherButtonTitles: nil];
[alert show];
[alert release];
}
The problem is that sometimes a web doesn't load for other things and not because it has a bad connection. I hope that there's a better way to check the WiFi. Any idea?
I suggest you follow the link and read the best marked answer given in there. It worked perfectly with me.
How to check for an active Internet connection on iOS or OSX?
I need to protect my code against possible errors. If they arise then there's no point to run the app further, so I need to bring to the user some message and then exit the app. So, I'm checking the conditions and then bringing alert:
if (someError){
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error" message:#"No database file exist. App will close now." delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
[alert release];
}
And in the delegate method I'm closing the app using NSAssert:
-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
if (buttonIndex == 0) {
NSAssert(0, #"closing");
}
}
Also, I have included delegate protocol in header. However, the app just brings alert but after pressing OK it just freezes, and I'm getting some message "CoreAnimation: ignoring exception: closing". What am I missing or what other options exits?
You should not do that, it is against Apple HIG (Human Interface Guidelines):
iPhone applications should never quit programmatically because doing so looks like a crash to the user.
It is always better to provide some kind of feedback to the user about the error that occured and provide a way to restart the process without restarting the app. However, if you really, really want, you can use
exit(0);
suppose you create a new iOS app from scratch, with just one single window.
then you put this code in the appDelegate application didFinishLaunching method :
UIAlertView *myAlert = [[UIAlertView alloc]
initWithTitle:#"alert"
message:#"message"
delegate:nil /* same problem with 'delegate:self' */
cancelButtonTitle:nil
otherButtonTitles:#"Ok", nil];
[myAlert show];
[myAlert release];
build and run in simulator 4.1, attach instrument, and...
this causes each time a memory leak.
in simulator 3.1.2 on leopard, no problem at all.
Of course, in a real app, the UIalertView is trigerred by a button, but the result is identical.
What is the problem ?
is UIAlertView buggy until iOS4 ?
Don't check for leaks in a simulator. It doesn't have the same memory model so reports leaks when there aren't any.
Test on a real device and if the leak is still there, report it as a bug to Apple :)