Passing the values between view controllers in iOS 7

Question

Here's the situation. I have 3 view controllers named as A, B and C.

I'm navigating from A to B and passing some string , call it as receivedMember.

In B when I write NSLog(@"Name is %@", _receivedMember); // it prints the value that was passed from A

Then from B, I'm navigating to C and again returning to B. So when I returned to B, I checked the value of name. It is null.

  -(void) viewDidAppear:(BOOL)animated{

     NSLog(@"DID APPEAR %@\n", _receivedMember);   // (null)
    }

    -(void) viewWillAppear:(BOOL)animated
    {
       NSLog(@"WILL APPEAR %@\n", _receivedMember); // (null)
    }

EDIT Here is the code

In class A, A ---> B

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"searchpage"])
    {
        B *cl = segue.destinationViewController;

        cl.receivedMember = strMemberType;

    }
}

I'm getting the strMemberType from pickerview,

-(void) pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent: (NSInteger)component
{

        strMemberType = [memberTypeArray objectAtIndex:row];

}

In class C, C ---> B

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"backToSearchSegue"])
    {
        B *cs = segue.destinationViewController;
    }
}

B.h

@property (nonatomic, copy) NSString *receivedMember;

How can I get the same value when I return to B from C.? I'm naive in iOS, so please help me out. Is there anyway I can store them in cache file? So that I can access it in any class.

Can you please give some links or write the code? I'm naive in iOS. — Aniruddha, Aug 07 '14 at 07:25
once check in class B ,some where you are clearing the data in _name. — Balu, Aug 07 '14 at 07:25
Or you can use NSUSerDeafults simply... Save value when you are switching from B to C..and Retrive again in C to B's ViewWillAppear — BhushanVU, Aug 07 '14 at 07:26
Show your code and look at other answers - you're probably creating a new instance of B and pushing it... Don't use the app delegate for this stuff @Anbu.Karthik — Wain, Aug 07 '14 at 07:29
you save value as globle NSUserDefault. and use it anywhare. — Kirit Modi, Aug 07 '14 at 07:32
`1.`Have you checked that your segue from C->B is being executed? `2.`You aren't setting class B's `name` property in your segue from C->B so it will be nil by default. — Robotic Cat, Aug 07 '14 at 08:15
@DownVoter explain the reason. Title might have mislead you, but take a time to read the entire question before down voting. — Aniruddha, Aug 07 '14 at 08:31
In your A->B segue you have `cl.receivedMember = strMemberType;`. Where is the equivalent code in your C->B segue (`cs.receivedMember = strMemberType`)? — Robotic Cat, Aug 07 '14 at 08:48
I'm not using `strMemberType` in `C`. Still I need to do that? — Aniruddha, Aug 07 '14 at 08:51
`backToSearchSegue` should not be a new push segue. See http://stackoverflow.com/questions/12561735/what-are-unwind-segues-for-and-how-do-you-use-them — Wain, Aug 07 '14 at 09:17

score 2 · Answer 1 · edited May 23 '17 at 11:58

in iOS the data passing method in used in several ways,

example 1.

AppDelegate

use this link How to pass data from AppDelegate to ViewController?

example 2:

NSObject class method

use this link Sending data from one ViewController to another.

example 3 :

using segue method.

use this link ios which is the best way to pass data from one viewcontroller to another . through singleton class or *.h file?

example 4 :

singleton class method

use this http://klanguedoc.hubpages.com/hub/iOS-5-How-To-Share-Data-Between-View-Controllers-using-a-Singleton

example 5 :

NSUserDefaults

use this link : Pass data from one ViewController to another ViewController using NSUserdefaults

if u need more assistance , i help with u, – Anbu.Karthik Aug 07 '14 at 07:35 — Anbu.Karthik, Aug 07 '14 at 07:35

score 1 · Answer 2 · edited May 23 '17 at 11:43

1

You will have to use NSUserDefault or Singleton to handle the values of varaiables accross various Controllers.

These both are used in such a scenario where you need to maintain and access the variable values across multiple View Controllers. You can opt for either one based on your choice. NSUserDefault can store multiple key-value pairs that are accessible globally throughout the app. Singleton helps you create a object / variable which is static and hence no other instance of it is created afterwards. Only a single instance is retained throughout the app.

The following links might help you.

Singleton Tutorial

Another Singleton Guide

NSUserDefault Tutorial

Another NSUserDefault Tutorial

Hope this helps !

edited May 23 '17 at 11:43

Community

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answered Aug 07 '14 at 07:34

Dhrumil

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Thanks, I will check out the links and get back to you. – Aniruddha Aug 07 '14 at 07:40
I have updated the code, can you please have a look? – Aniruddha Aug 07 '14 at 07:45

score 0 · Answer 3 · answered Feb 02 '15 at 09:47

When you are returning from C to B basically you creating another another instance of B in memory which is not same as what you had when you came from A. Remove sgeue pushviewcontroller on backbutton just type following on backbutton IBAction click.

[self.navigationController popViewControllerAnimated:YES];

It will take you to B which you had when you came from A and and on viewWillAppear your value will remain there

Whenever you push your viewControllers it gets added to self.navigationalController ViewControllers array.

Passing the values between view controllers in iOS 7

3 Answers3