Login form for Evernote in ios - iphone

Question

i downloaed the evernote sample app from the evernote site for Iphone sdk.i integrated it with my application,i can save note to evernote and import back ,but the only problem is login form missing.the username and password is stored statically in the sample app.i dont know how to authenticate this to dynamically.it is using singlton desing.
in.h
extern NSString * const username;
extern NSString * const password;
#interface evernoteloginpage : UIViewController {
.m
NSString * const username = #"nips55";
NSString * const password = #"annyan555";
#implementation evernoteloginpage
but i need it dynamically,i have two textfiled and a login button i need to add the textfiled values to username and password.i tried a lot but no luck.if anyone knows how to add a loginform for evernote ,please help me.
thanks in advance.
EDIT
now i sucessfully login with the help of this code,but again ther problem is if the login is sucess it will redirect to next page as shown in the code,if the user enter the wrong username or password,ithe app crashes.how to handele the rror mamangement in this code.
-(IBAction)_clickevernotelogin:(id)sender
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
// Keep this key private
NSString *consumerKey = [[[NSString alloc]
initWithString: #"app" ] autorelease];
[[NSUserDefaults standardUserDefaults] setObject:consumerKey forKey:#"consumerkeyevrnote"];
NSString *consumerSecret = [[[NSString alloc]
initWithString: #"12345678"] autorelease];
// For testing we use the sandbox server.
NSURL *userStoreUri = [[[NSURL alloc]
initWithString: #"https://www.evernote.com/edam/user"] autorelease];
NSString *noteStoreUriBase = [[[NSString alloc]
initWithString: #"https://www.evernote.com/edam/note/"] autorelease];
// These are for test purposes. At some point the user will provide his/her own.
NSString *username = [[[NSString alloc]
initWithString: _txtevernoteUsername.text] autorelease];
NSString *password = [[[NSString alloc]
initWithString: _txtevernotepasswrd.text] autorelease];
[[NSUserDefaults standardUserDefaults] setObject:_txtevernoteUsername.text forKey:#"usernameevernote"];
[[NSUserDefaults standardUserDefaults] setObject:_txtevernotepasswrd.text forKey:#"passwrdevernote"];
THTTPClient *userStoreHttpClient = [[[THTTPClient alloc]
initWithURL:userStoreUri] autorelease];
TBinaryProtocol *userStoreProtocol = [[[TBinaryProtocol alloc]
initWithTransport:userStoreHttpClient] autorelease];
EDAMUserStoreClient *userStore = [[[EDAMUserStoreClient alloc]
initWithProtocol:userStoreProtocol] autorelease];
EDAMNotebook* defaultNotebook = NULL;
BOOL versionOk = [userStore checkVersion:#"Cocoa EDAMTest" :
[EDAMUserStoreConstants EDAM_VERSION_MAJOR] :
[EDAMUserStoreConstants EDAM_VERSION_MINOR]];
if (versionOk == YES)
{
EDAMAuthenticationResult* authResult =
[userStore authenticate:username :password
:consumerKey :consumerSecret];
EDAMUser *user = [authResult user];
NSString *authToken = [authResult authenticationToken];
NSLog(#"Authentication was successful for: %#", [user username]);
NSLog(#"Authentication token: %#", authToken);
NSURL *noteStoreUri = [[[NSURL alloc]
initWithString:[NSString stringWithFormat:#"%#%#",
noteStoreUriBase, [user shardId]] ]autorelease];
[pool drain];
// this is next page if the login sucess
evernotemainpage *detailViewController = [[evernotemainpage alloc] initWithNibName:#"evernotemainpage" bundle:nil];
//detailViewController.firstString = firstString;
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController release];
}
}

Answer 1

Unfortunately, the Eevernote API currently does not contain any code samples for iOS. If you need information or an example on how to do this check out this article.
http://digitalpericope.net/?p=27