Failure to pass variables/values to another view controller (not working)

Question

Object: change the label's text in ViewControllerB

(In the ViewControllerA.m)

- (IBAction)ReturnToMenu
{
    ViewControllerB *ViewControllerB =
    [self.storyboard instantiateViewControllerWithIdentifier:@"ViewControllerB"];
    ViewControllerB.scorelabel.text=@"WHY IS IT NOT WORKING";
    [self presentViewController:GameOverViewController animated:YES completion:nil];
}

Well, this isn't working. I've exhausted all my options. This is such an elementary question, but please help me out.

P.S. @"Why is it not working" is just a temporary thing, a variable from ViewControllerA is supposed to take its place.

P.P.S. I tried out Passing Data between View Controllers, but it didn't work. I'm not sure what I'm doing wrong here

Why didn't you comment in the previous question you'd asked? Did you try what I had suggested? — Neeku, Dec 01 '13 at 13:11
Possible duplicate of your own question: http://stackoverflow.com/questions/20311142/how-to-access-variables-of-other-classes-in-objective-c-ios/20311255#20311255 — Neeku, Dec 01 '13 at 13:12
@Neeku Sorry, It's just that the post was filled with negativity and I really didn't want to go back there :( And yes, as you can see, I tried exactly what you told me. It is not working. — Gyuhyeon Lee, Dec 01 '13 at 13:13
It's not what I said. Just try making an instance of the ViewController, away from the storyboard. — Neeku, Dec 01 '13 at 13:15
Just making an instance of the viewcontroller didn't seem to work. Doesn't it just make "ANOTHER" instance? That is, I am playing with another object's variable, not the actual view that I generated? — Gyuhyeon Lee, Dec 01 '13 at 13:17
edit: Thanks, I think the problem wasn't in instantiating, but in accessing the label directly. It's not supposed to work for some reason? — Gyuhyeon Lee, Dec 01 '13 at 13:21
Check out my answer. That way, you'll always have only one instance, and the property must be passed safely. — Neeku, Dec 01 '13 at 13:36

score 0 · Answer 1 · answered Dec 01 '13 at 13:11

0

You should not try to manipulate another view controller's views directly. It's bad design, and in many cases (like yours) it doesn't work.

Instead of setting a label's text, add a string property "score". Set that after instantiating the VC.

Then, in "ViewController8"s viewWillAppear method, install the score property into the label.

Problem solved.

answered Dec 01 '13 at 13:11

Duncan C

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OH MY GOD. My 3 hour adventure came to an end. You are a life saver. Oh god thank you so much oh god – Gyuhyeon Lee Dec 01 '13 at 13:19

Zafer Fatih Koyuncu · Answer 2 · 2013-12-01T13:34:36.677

Here I present a modal view controller from my main view controller to show locations which I previously got from foursquare api.

    LocationPickerVC *vc = (LocationPickerVC*)[self.storyboard instantiateViewControllerWithIdentifier:@"modal"];
    if([vc respondsToSelector:@selector(setLocations:) ])
            vc.locations = items;
    [self.formSheetController presentViewController:vc animated:YES completion:nil];

[EDIT]

Make sure you set storyboard id in your storyboard (for the code below it is "modal"). Also my LocationPickerVC has this interface.

    @interface LocationPickerVC : UIViewController<UITableViewDataSource, UITableViewDelegate>
    @property(strong, nonatomic) NSMutableArray *locations;
    @end

Neeku · Accepted Answer · 2013-12-03T10:42:29.623

-1

OK, try this:

In your ViewController1.h that the property score is declared, add this:

+ (ViewController1 *) sharedController;

In your ViewController1.m add this method:

+ (ViewController1 *)sharedController
{
    static ViewController1* staticVar = nil;

    if (staticVar == nil)
        staticVar = [[ViewController1 alloc] init];
    return staticVar;
}

Now, where ever in other ViewControllers you need something from ViewController1, import the header, and then get the property like this:

[[ViewController1 sharedController] score]

edited Dec 03 '13 at 10:42

answered Dec 01 '13 at 13:34

Neeku

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Sorry for the late reply, I was busy uploading it to the app store (although it might get rejected heh). Thanks, it worked! I didn't think about the class method, I probably should read a book from the start when I have the time. Have a nice day! – Gyuhyeon Lee Dec 01 '13 at 16:03
syntax error and type mismatch: `[[ViewController1 sharedController] score] = @"I hope it works this time!";` – vikingosegundo Dec 02 '13 at 20:48
@vikingosegundo Edit applied. – Neeku Dec 03 '13 at 07:32
this is still an syntax error `[[ViewController1 sharedController] score] = 100;` – vikingosegundo Dec 03 '13 at 09:26

Failure to pass variables/values to another view controller (not working)

3 Answers3