How to get Paypal transaction Id after getting paykey in paypal integration in iphone?

I am going to implement paypal in my iphone native app. But I am facig an issue in that.

I want to get my transaction Id regarding my PayKey. There is a direct method to get pay key in PayPal library to get PayKey but not a method to get transactionId.

Here is that method:

-(void)paymentSuccessWithKey:(NSString *)payKey andStatus:(PayPalPaymentStatus)paymentStatus;

As I am thinking IPN(Instant Payment Notification ) can help to resolve this issue but I don't know how to implement that one in my app?

Please help me to resolve this issue.

Thanks, Chandra Prakash

Fianlly I have got solution of my question.

I have got transaction Id using IPN.

When I selected ENABLE IPN Option from my PayPal account then all details send by paypal I have received on URL which I given from there I have got all required fields.

Here are a few links to help you

IPN Overview: https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/howto_html_instantpaymentnotif

IPN Documentation: https://cms.paypal.com/cms_content/US/en_US/files/developer/IPNGuide.pdf

IPN Variables: https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/e_howto_html_IPNandPDTVariables

IPN Script Example: https://cms.paypal.com/us/cgi-bin/?&cmd=_render-content&content_ID=developer/e_howto_admin_IPNImplementation

IPN Script Generator: https://www.paypaltech.com/SG2/

Thanks, Cp