Here is my question. How do I display an error if my app is unable to load my remote JSON file? I turned my wifi off on my computer and ran the app in the Simulator. It NSLogs the message that should be displayed if there is connection. How can I fix this? Thanks.
Here is my code:
- (void)viewDidLoad
{
[super viewDidLoad];
NSString *jsonStr = #"http://xxx.com/server.php?json=1";
NSURL *jsonURL = [NSURL URLWithString:jsonStr];
// NSData *jsonData = [NSData dataWithContentsOfURL:jsonURL];
// NSError *jsonError = nil;
NSURLRequest *jsonLoaded = [NSURLRequest requestWithURL:jsonURL];
if(!jsonLoaded) {
UIAlertView *alertView = [[UIAlertView alloc] init];
alertView.title = #"Error!";
alertView.message = #"A server with the specified hostname could not be found.\n\nPlease check your internet connection.";
[alertView addButtonWithTitle:#"Ok"];
[alertView show];
[alertView release];
NSLog(#"No connection, JSON not loaded...");
}
else {
NSLog(#"JSON loaded and ready to process...");
}
}
Your code just creates the request. It doesn't actually fetch the data. You need to use NSURLConnection to fetch the data.
There are multiple ways to fetch the data. This example is for iOS 5.0 or higher:
NSOperationQueue *q = [[[NSOperationQueue alloc] init] autorelease];
NSURLRequest *jsonRequest = [NSURLRequest requestWithURL:jsonURL];
[NSURLConnection sendAsynchronousRequest:jsonRequest
queue:q
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
// data was received
if (data)
{
NSLog(#"JSON loaded and ready to process...");
// ... process the data
}
// No data received
else
{
NSLog(#"No connection, JSON not loaded...");
// ... display your alert view
}
}];
You have not actually requested anything yet. Read here on how to make requests.
Basically, what you want to do is to implement NSURLConnectionDelegate protocol and override connection:didFailWithError: function to listen for failure event.
Related
i have a method for http connection, which was working fine for me until the server i am trying to have an invalid ssl certificate.
Since i am using
[NSURLConnection sendSynchronousRequest:returningResponse:error]
There is no chance to pass authentication challenge by using NSURLConnection delegate methods.
Now, i need to change my service call code as fast as possible.
My method returns the data received from the connection, that is the major problem i can not easily change mine to
NSURLConnection to initWithRequest:delegate:
My service call method is as follows;
-(id)serviceCall:(NSString*)str withURL:(NSString*)serviceUrl withIdentifier:(NSString*)type
{
globalURL = [[NSURL alloc] initWithString:serviceUrl];
shouldAllowSelfSignedCert = YES;
// if(ISDEBUG) NSLog(#"%#",serviceUrl);
NSMutableDictionary* json;
NSURLResponse* response;
NSData* responseData = [NSMutableData data];
NSError* error = nil;
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:globalURL];
[request setHTTPMethod:#"POST"];
[request setHTTPBody: [str dataUsingEncoding: NSUTF8StringEncoding]];
NSString* msgLength = [[NSString alloc] initWithFormat:#"%lu", (unsigned long)[str length]];
[request addValue:#"text/json; charset=utf-8" forHTTPHeaderField:#"Content-Type"];
[request addValue:msgLength forHTTPHeaderField:#"Content-Length"];
request.timeoutInterval = 180;
responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
if([type isEqualToString:#"image"])
{
if(ISDEBUG) NSLog(#"%#",responseData);
return responseData;
}
else
{
if(error)
{
UIAlertView *message = [[UIAlertView alloc] initWithTitle:NO_WS_CONNECTION message:#"" delegate:nil cancelButtonTitle:#"Ok" otherButtonTitles:nil];
if(ISDEBUG) NSLog(#"%#",error);
}
else
{
if(responseData !=nil)
{
json = [NSJSONSerialization
JSONObjectWithData:responseData
options:kNilOptions
error:&error];
}
else
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error" message:NO_WS_CONNECTION delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil, nil];
[alert show];
}
}
NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
if(ISDEBUG) NSLog(#"%#",responseString);
}
return json;
}
I hope i am clear enough.
What is your advise?
Thanks.
You should have a good reason to do it synchronously, so, I will try to help you without changing the flow.
Try wrapping the request into a class where you can implement the request using initWithRequest:delegate: and make the class return the response using block.
You will have something like:
[YourRequestClass requestWithURL:serviceURL callback:^(NSData *yourData, NSError *error){
}];
Ok, at this point you have a new tool that makes ASYNCHRONOUS requests, make the authentication challenge stuff for you and returns the result on a block.
Now, you can simply use dispatch_semaphore to block your thread until the request returns a response ....
-(id)serviceCall:(NSString*)str withURL:(NSString*)serviceUrl withIdentifier:(NSString*)type {
__block NSData *myData = nil;
dispatch_semaphore_t sem = dispatch_semaphore_create(0);
[YourRequestClass requestWithURL:serviceUrl callback:^(NSData *yourData, NSError *error){
//ignoring error (this is an example !)
myData = yourData;
dispatch_semaphore_signal(sem);
}];
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
//Use myData and make yourObject here!
return yourObject;
}
Note that It's just an example, and I'm just trying to pointing you the right way ... I didn't test this code, but I believe it should work as expected!
I am performing JSON POST request by clicking UIButton and after the submission, segue perform can be done. So, After submitting values, I cannot perform POST request anymore. It shows status code 200 and response is OK. But, data is not reflected in the Backend. Here is my code:
(IBAction)transitsurveydone:(id)sender {
if([tempArray count]!=0){
/* alert= [[UIAlertView alloc] initWithTitle:#"Survey Submission"
message:#"Please Enter your location"
delegate:self
cancelButtonTitle:#"Modify"
otherButtonTitles:#"Submit",nil];
alert.alertViewStyle = UIAlertViewStylePlainTextInput;
alert.tag=2;
[alert show];*/
NSLog(#"Caption array is %# %#",captionArray,tempArray);
NSURL *URL = [NSURL URLWithString:[NSString stringWithFormat:#"myURL"]];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:URL];
[request setHTTPMethod:#"POST"];
[request setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
NSMutableDictionary *postDict = [[NSMutableDictionary alloc]init];
NSMutableDictionary *d=[[NSMutableDictionary alloc] initWithObjectsAndKeys:#10,#"\"Bus\"", nil];
NSMutableArray *m=[[NSMutableArray alloc] init];
NSString *str1,*str2,*str3,*str4;
// Checking the format
if(tempArray.count==1){
for (int x=0; x<1; x++) {
str1=[NSString stringWithFormat:#"\"%#\"",[captionArray objectAtIndex:x]];
[d setObject:[tempArray objectAtIndex:x] forKey:str1];
}
[request setHTTPBody:[[NSString stringWithFormat: #"{\n \"instance\" : %#,\n \"response_method\": \"web\",\n \"routes\": [\n {%#:%#}\n ]\n}",randomString,str1,[d objectForKey:str1] ]dataUsingEncoding:NSUTF8StringEncoding]];
}
NSLog(#"%#:%#",str1,[d objectForKey:str1]);
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest:request
completionHandler:
^(NSData *data, NSURLResponse *response, NSError *error) {
if (error) {
// Handle error...
return;
}
if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
NSLog(#"Response HTTP Status code: %ld\n", (long)[(NSHTTPURLResponse *)response statusCode]);
NSLog(#"Response HTTP Headers:\n%#\n", [(NSHTTPURLResponse *)response allHeaderFields]);
}
NSString* body = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"Response Body:\n%#\n", body);
}];
[task resume];
NSHTTPURLResponse *response = nil;
NSError *error = nil;
NSData *respData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSLog(#"~~~~~ Status code: %d", [response statusCode]);
if([response statusCode]==200){
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:#"Transit Survey submitted" delegate:self cancelButtonTitle:nil otherButtonTitles:nil];
alert.transform = CGAffineTransformMakeTranslation( 10, 740);
[alert show];
[self performSelector:#selector(dismissAlert:) withObject:alert afterDelay:1.0f];
submitteddonthide=NO;
}
else{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:#"Transit Survey Submission Failed" delegate:self cancelButtonTitle:nil otherButtonTitles:nil];
alert.transform = CGAffineTransformMakeTranslation( 10, 740);
[alert show];
[self performSelector:#selector(dismissAlert:) withObject:alert afterDelay:1.0f];
}
if([prefs integerForKey:#"humandone"]==1){
[self performSegueWithIdentifier:#"transittohuman" sender:nil];
}
else{
[self performSegueWithIdentifier:#"gobackfromtransit" sender:nil];
}
}
`
The above code is in IBAction
Your code looks fine and there is no any issues.
If this issue is happens all the time, add "Advanced Rest Client" add-on to chrome browser and test your server URL passing respective input values. If this process also can't be able to update values on your backend there should be some issue on your backend.
A couple of thoughts:
You are using status code to determine whether the server inserted the data correctly or not. You should actually have your web service build an affirmative response (in JSON, would be great) that says whether data was successfully inserted or not. You should not be relying solely on the web server's request response code.
I would observe the request with something like Charles and make sure it looks OK.
You're building a JSON request manually, which is very fragile. I would suggest using Charles to observe the request, and copy and paste it into http://jsonlint.com and make sure it's OK.
Even better, use NSJSONSerialization which is more robust and easier to use.
Also, you're sending this request twice. Lose this second request (you shouldn't do synchronous requests, anyway) and put all of your confirmation logic inside the session's completion handler block.
Yes. After struggling a bit, Clearing cookies helped me a lot :-
Here is a chunk of code, which is pretty much simple
NSHTTPCookieStorage *cookieStorage = [NSHTTPCookieStorage sharedHTTPCookieStorage];
NSArray *cookies = [cookieStorage cookiesForURL:[NSURL URLWithString:urlString]];
for (NSHTTPCookie *cookie in cookies) {
NSLog(#"Deleting cookie for domain: %#", [cookie domain]);
[cookieStorage deleteCookie:cookie];
}
Thank you Mr. reddys and Rob for the suggestions
I am currently using this in my Xcode 5 application and I can't seem to get it working
NSString *bundleVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:#"CFBundleShortVersionString"];
NSString *latestVersionString = [NSString stringWithContentsOfURL:[NSURL URLWithString:#"http://mywebsite.com/version.txt"] encoding:NSUTF8StringEncoding error:nil];
#import NSString+compareToVersion.h
if ([bundleVersion isOlderThanVersion:latestVersionString]) {
// show a blocking modal view, with a button to link to the app store}
First, I do not recommend using synchronous network calls, regardless of how small the .txt file may be. You can try this for your code: Make sure to include <UIAlertViewDelegate> in your .h file first.
- (void)applicationDidBecomeActive:(UIApplication *)application
{
[[UIApplication sharedApplication]beginIgnoringInteractionEvents];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:
[NSURL URLWithString:#"http://mywebsite.com/version.txt"]];
request.timeoutInterval = 10.0;
request.cachePolicy = NSURLRequestReloadIgnoringLocalAndRemoteCacheData;
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:
^(NSURLResponse *response, NSData *data, NSError *connectionError)
{
if (data)
{
NSString *bundleVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:#"CFBundleShortVersionString"];
NSString *latestVersionString = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
if (![bundleVersion isEqualToString:latestVersionString])
{
// The two strings are not equal, dispatch to the UI thread and show a UIAlertView
dispatch_async(dispatch_get_main_queue(), ^
{
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:#"Update App!"
message:#"Please download the newer version available first on the App Store!"
delegate:self cancelButtonTitle:#"App Store"
otherButtonTitles:nil];
[alertView show];
[[UIApplication sharedApplication]endIgnoringInteractionEvents];
});
}
else
{
// Up to date; no new version is available, proceed to game play routines
[[UIApplication sharedApplication]endIgnoringInteractionEvents];
}
}
else
{
// No internet, or there is no data at the url, show error
// Uncomment below line if you want the user to interact with app again
// [[UIApplication sharedApplication]endIgnoringInteractionEvents];
}
}];
}
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
[[UIApplication sharedApplication]openURL:[NSURL URLWithString:#"Your App Store app link here"]];
}
First, check the value of latestVersionString in the debugger. Make sure it is the value you want it to be (and not e.g. nil). Also, declare an NSError * to capture any error that arises from trying to initialise a string from an HTTP URL (consider the case where there may be no internet connection, or temporary routing or DNS issue etc.).
NSError *error = nil;
NSString *latestVersionString = [NSString stringWithContentsOfURL:[NSURL URLWithString:#"http://mywebsite.com/version.txt"] encoding:NSUTF8StringEncoding error:&error];
if (error != nil)
{
// figure out what went wrong based on the error
}
else
{
// check latestVersionString contains something valid and then compare
// with bundleVersion.
}
If both bundleVersion and latestVersionString contain what you expect, then the issue may be in the isOlderThanVersion: method.
I have read all detail about stripe integration in iOS app from here. And run the sample app of stripe by downloading from here.
On running this app, I am getting following error when I am testing on iPhone Simulator.
Following method is calling after token received::
- (void)hasError:(NSError *)error
{
UIAlertView *message = [[UIAlertView alloc] initWithTitle:NSLocalizedString(#"Error", #"Error")
message:[error localizedDescription]
delegate:nil
cancelButtonTitle:NSLocalizedString(#"OK", #"OK")
otherButtonTitles:nil];
[message show];
}
//--Called after sucessfully token received ::
- (void)hasToken:(STPToken *)token
{
NSLog(#"Received token %#", token.tokenId);
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:#"https://example.com"]];
request.HTTPMethod = #"POST";
NSString *body = [NSString stringWithFormat:#"stripeToken=%#", token.tokenId];
request.HTTPBody = [body dataUsingEncoding:NSUTF8StringEncoding];
[MBProgressHUD showHUDAddedTo:self.view animated:YES];
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
[MBProgressHUD hideHUDForView:self.view animated:YES];
if (error) {
[self hasError:error];
} else {
NSString *str = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"\nStr is :::%#",str);
NSLog(#"\n\nResponse is :::%#",response);
[self.navigationController popViewControllerAnimated:YES];
}
}];
}
Please tell me how to resolve this problem and make a credit card payment on iOS app because in this sample code, there is information about payment.
You are using example.com. Replace it first with your own server address.
For charging a card in Stripe you need a server module. Here is detail explanation of how to charge your card via server module. If you are using parse as backend you can always use cloudcode for this purpose.
Here is raywenderlich's explanation of making payment system with python backend.
I have searched for awhile and tried many things, but I cannot get this error to go away. I have a table that is refreshed by a pull down method. I also use Apple's Reachability to determine internet connectivity. When I run my application WITH internet, and then while the app is running, shut the internet off, my app crashes trying to display a UIAlertView. Although, when I start my app WITHOUT internet and then turn on internet while the app is running and turn it back off, the app does not crash and everything works as it should. Any help would be greatly appreciated.
The error occurs on the [message show] line.
Edited code:
- (void)loadCallList {
NSURL *theURL = [NSURL URLWithString:#"http://www.wccca.com/PITS/"];
NSURLRequest *theRequest = [NSURLRequest requestWithURL:theURL cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:10.0];
NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection) {
NSLog(#"Reachable");
self.headerHeight = 45.0;
NSData *data = [[NSData alloc] initWithContentsOfURL:theURL];
xpathParser = [[TFHpple alloc] initWithHTMLData:data];
NSArray *elements = [xpathParser searchWithXPathQuery:#"//input[#id='hidXMLID']//#value"];
if (elements.count >= 1) {
TFHppleElement *element = [elements objectAtIndex:0];
TFHppleElement *child = [element.children objectAtIndex:0];
NSString *idValue = [child content];
NSString *idwithxml = [idValue stringByAppendingFormat:#".xml"];
NSString *url = #"http://www.wccca.com/PITS/xml/fire_data_";
NSString *finalurl = [url stringByAppendingString:idwithxml];
xmlParser = [[XMLParser alloc] loadXMLByURL:finalurl];
[callsTableView reloadData];
}
}
else {
NSLog(#"Not Reachable");
self.headerHeight = 0.0;
UIAlertView *message = [[UIAlertView alloc] initWithTitle:#"No Internet Connection"
message:#"Please check your internet connection and pull down to refresh."
delegate:self
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[message show];
[message release];
}
[pull finishedLoading];
}
I tested the following method using sendAsynchronousRequest:queue:completionHandler: as the method to download data from the URL. It seems to work fine, I can get the else clause to fire, either by messing up the URL or making the timeout interval .1 seconds.
NSURL *theURL = [NSURL URLWithString:#"http://www.wccca.com/PITS/"];
NSURLRequest *theRequest = [NSURLRequest requestWithURL:theURL cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:5];
[NSURLConnection sendAsynchronousRequest:theRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (error == nil) {
//do whatever with the data. I converted it to a string for testing purposes.
NSString *text = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"%#",text);
}else{
NSLog(#"%#",error.localizedDescription);
UIAlertView *message = [[UIAlertView alloc] initWithTitle:#"No Internet Connection" message:#"Please check your internet connection and pull down to refresh." delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
[message show];
}
}];
You have two problems:
You shouldn't be using Reachability to determine whether there is an internet connection. Reachability is only useful to determine when an offline connection comes back online. Really. Making the networking calls is sometimes enough to power up the radios and connect so if you try to pre-check whether there is an internet connection the radios will remain off.
The second problem is that no synchronous networking calls can be made on the main thread. This includes Reachability and [NSData dataWithContentsOfURL:xxx]. Make them on a secondary thread using Grand Central Dispatch, NSOperationQueues, NSURLConnections, or NSThreads. Otherwise your application can lock up if the network isn't in good shape and the system watchdog timer will kill your app.