Passing data in NSString format from LoginViewController to FirstViewController - objective-c

Question

LoginViewController is my initial view controller. Email address is an input in the LoginViewController and I am trying to send it to FirstViewController. I went through a lot of solutions posted here but was unsuccessful to find a link to my answer.
Please have a look at my code and tell me where I am going wrong. I am stuck at this point from a couple of days. My main problem is that, the output of emailString shows null when I print it to see if it was carried to the FirstViewController.
FYI - I am using storyboard. I have a Tab Bar Controller which has three tabs and FirstViewController is the first tab page.
LoginViewController.h
#import <UIKit/UIKit.h>
#import "FirstViewController.h"
#interface LoginViewController : UIViewController{
NSString *email;
}
- (IBAction)LoginButton:(id)sender;
- (IBAction)CancelButton:(id)sender;
- (IBAction)dismissKeyboard:(id)sender;
#property (weak, nonatomic) IBOutlet UITextField *EmailField;
#property (weak, nonatomic) IBOutlet UITextField *PasswordField;
#end
LoginViewController.m
#import "LoginViewController.h"
#import "FirstViewController.h"
#define USERNAME #"abc#gmail.com"
#interface LoginViewController ()
#end
#implementation LoginViewController
#synthesize EmailField;
#synthesize PasswordField;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
email = [[NSString alloc] init];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (IBAction)LoginButton:(id)sender {
email = EmailField.text;
if([EmailField.text isEqualToString:USERNAME])
{
FirstViewController *fvc = [[FirstViewController alloc]initWithNibName:#"FirstViewController" bundle:nil];
fvc.emailString = [[NSString alloc] initWithFormat:#"%#",EmailField.text];
// fvc.emailString = email;
[self.navigationController pushViewController:fvc animated:YES];
}
[EmailField resignFirstResponder];
}
- (IBAction)CancelButton:(id)sender {
NSLog(#"Cancel button pressed!!!");
[EmailField resignFirstResponder];
[PasswordField resignFirstResponder];
}
- (IBAction)dismissKeyboard:(id)sender {
[EmailField resignFirstResponder];
[PasswordField resignFirstResponder];
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
[self LoginButton:nil];
[textField resignFirstResponder];
return YES;
}
#end
FirstViewController.h
#import <UIKit/UIKit.h>
#import "LoginViewController.h"
#interface FirstViewController : UIViewController
#property (weak, nonatomic) IBOutlet UILabel *emailLabel;
#property (nonatomic, retain) NSMutableData *receivedData;
#property (copy) NSString *emailString;
FirstViewController.m
#import "FirstViewController.h"
#interface FirstViewController ()
#end
#implementation FirstViewController
#synthesize emailLabel;
#synthesize receivedData;
#synthesize emailString;
- (void)viewDidLoad
{
[super viewDidLoad];
[emailLabel setText: emailString];
NSString *theURL = [NSURL URLWithString:[NSString stringWithFormat:#"http://.....email=%#",emailString]];
NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:theURL
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:req delegate:self];
if(connection){
NSLog(#"connection successful");
NSLog(#"%#",emailString);
receivedData = [NSMutableData data];
}
else{
NSLog(#"connection failed");
}
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[receivedData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
[receivedData setLength:0];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
NSLog(#"Success");
NSLog(#"Received %d bytes of data",[receivedData length]);
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
#end
I tried implementing prepareFOrSegue method in LoginViewController too. But it still didnot make any change. This is the code I have written in it.
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if([segue.identifier isEqualToString:#"showDetailSegue"])
{
NSString *email = EmailField.text;
NSLog (#"++++++++++ %#", email);
FirstViewController *fvc = [segue destinationViewController];
fvc.emailString=email;
}
}
Screenshot of Storyboard:

Answer 1

If you are using StoryBoards I'd strongly suggest you use segues to call the different view controllers. That way you can push vc's and pass info relatively easily.
You can override the native method prepareForSegue in your Login VC, and set the properties there. You can name your segue id as anything in the storyboard.
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([[segue identifier] isEqualToString:#"firstVC"]) {
FirstViewController *firstVC = [segue destinationViewController];
firstVC.emailString = EmailField.text;
}
}
if you really want, and I'd advise against it vs. using static variables is
NSUserDefaults.
[[NSUserDefaults standardUserDefaults]
setObject:EmailField.text forKey:#"emailString"];
to get it back later
NSString *emailString = [[NSUserDefaults standardUserDefaults]
stringForKey:#"emailString"];
NSLog(#"%#",emailString);

Answer 2

I would save the Email and password in the IOS Keychain securely instead of passing it in between views.
https://developer.apple.com/library/ios/#documentation/security/conceptual/keychainServConcepts/iPhoneTasks/iPhoneTasks.html#//apple_ref/doc/uid/TP30000897-CH208-SW1

Answer 3

I got the solution.
The only three lines requires for me to add in the prepareForSegue were these three and I got my program working
FirstViewController* fvc = [[FirstViewController alloc] init];
UITabBarController *tbc = [segue destinationViewController];
fvc = (FirstViewController *) [[tbc customizableViewControllers] objectAtIndex:0];
Thanks everyone!