post request json parsing - iphone

Question

question_id = 28, value = 'yes', null for now
then function will get
{
question_id = 22,
value = 'yes',
array = (9=>1, 28 => 0)
}
9 is id 1 for yes and 0 for no.
the array stores all previous questions and answers
and display the result if there is no question.
How do i implement/post/ this using two action buttons yes and no??

Answer 1

You can use the following code snippet, as described in this article:
Here, I simple describe how can use of POST method.
1. Set post string with actual username and password.
NSString *post = [NSString stringWithFormat:#"&Username=%#&Password=%#",#"username",#"password"];
2. Encode the post string using NSASCIIStringEncoding and also the post string you need to send in NSData format.
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
You need to send the actual length of your data. Calculate the length
of the post string.
NSString *postLength = [NSString stringWithFormat:#"%d",[postData length]];
3. Create a Urlrequest with all the properties like HTTP method, http header field with length of the post string. Create URLRequest
object and initialize it.
NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
Set the Url for which your going to send the data to that request.
[request setURL:[NSURL URLWithString:[NSString stringWithFormat:#"http://www.abcde.com/xyz/login.aspx"]]];
Now, set HTTP method (POST or GET). Write this lines as it is in
your code.
[request setHTTPMethod:#"POST"];
Set HTTP header field with length of the post data.
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
Also set the Encoded value for HTTP header Field.
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Current-Type"];
Set the HTTPBody of the urlrequest with postData.
[request setHTTPBody:postData];
4. Now, create URLConnection object. Initialize it with the URLRequest.
NSURLConnection *conn = [[NSURLConnection alloc]initWithRequest:request delegate:self];
It returns the initialized url connection and begins to load the data
for the url request. You can check that whether you URL connection
is done properly or not using just if/else statement as below.
if(conn)
{
NSLog(#”Connection Successful”)
}
else
{
NSLog(#”Connection could not be made”);
}
5. To receive the data from the HTTP request , you can use the delegate methods provided by the URLConnection Class Reference.
Delegate methods are as below.
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data
Above method is used to receive the data which we get using post
method.
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
This method , you can use to receive the error report in case of
connection is not made to server.
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
The above method is used to process the data after connection has made
successfully.
Also Refer This and This documentation for POST method.
And here is best example with source code of HTTPPost Method.
EDITED:
-(void) buttonPressed:(id) sender
{
NSURL *url = [NSURL URLWithString:#"URL"];
ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
[request setShouldStreamPostDataFromDisk:YES];
[request setDidFinishSelector:#selector(uploadFinished:)];
[request setDidFailSelector:#selector(uploadFail:)];
[request setTimeOutSeconds:300];
[request setPostValue:#"Login" forKey:#"action"];
[request setPostValue:Yourvalue1 forKey:#"key1"];
[request setPostValue:Yourvalue2 forKey:#"key2"];
.
.
.
request.delegate = self;
[self.sendLoader startAnimating];
[request startAsynchronous];
}
#pragma Mark -
#pragma Mark - ASIHTTPRequest Methods
- (void) uploadFinished:(ASIHTTPRequest *)request
{
NSString *str = [request responseString];// convert it as JSON also.
}
- (void) uploadFail:(ASIHTTPRequest *)request
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(#"Error",#"") message:NSLocalizedString(#"Connection failed !!",#"") delegate:nil cancelButtonTitle:NSLocalizedString(#"OK",#"") otherButtonTitles:nil];
[alert show];
}