IOS: Call method in another controller

Question

I have two separated classes FirstController and SecondController, created with storyboards. The problem is that I want to call method in SecondController.m, FROM FirstController. For ex. :

SecondController.m

-(void)myMethod:(CGPoint)pt {...} // It's important that there is a paramterer

FirstController.m

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    // Call myMethod
 }

How to do this in the easiest way?

Update: I want to use notification from 'aBilal17' link:

[[NSNotificationCenter defaultCenter] removeObserver:self name:@"updateLeftTable"
                                              object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
                                     selector:@selector(checkRes:)     name:@"updateLeftTable" object:nil];

(..)

-(void)checkRes:(NSNotification *)notification
{
   if ([[notification name] isEqualToString:@"updateLeftTable"])
   {
      [myMethod ?
    }
}

In other class:

[[NSNotificationCenter defaultCenter] postNotificationName:@"updateLeftTable" object:self];

But now, how to pass my CGPoint argument using this?

What have you looked at? There are hundreds of questions regarding this sort of thing on stackoverflow. — Popeye, Apr 09 '13 at 14:53
Unless you're talking about delegate protocols or notifications, you may wish to introduce more model in your MVC. You generally shouldn't be calling code from other controllers. — Marcus Adams, Apr 09 '13 at 15:30

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

1

You can use NSNotification or custom delegate for it.

check my ans on the following link.

Can't use reloadData from another class

Both options are available on it.

edited May 23 '17 at 11:43

Community

1
1

answered Apr 09 '13 at 14:55

aBilal17

2,974
2
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23

Thanks! Notifications seems to be the best solution. But how to pass an argument (CGPoint) using it (Let's say that I have exactly the same notification as in your link at this moment)? – user2262230 Apr 09 '13 at 16:29

score 0 · Answer 2 · answered Apr 09 '13 at 17:34

To pass CGPoint using NSNotificationCenter, you'll need to use NSValue:

NSValue *pointValue = [NSValue valueWithCGPoint:myPoint];
[[NSNotificationCenter defaultCenter] postNotificationName:@"updateLeftTable" object:pointValue];

In your checkRes: method, you can obtain the point with the object property of the passed NSNotification:

NSValue *pointValue = (NSValue *)[notification object];
CGPoint myPoint = [pointValue CGPointValue];

score -1 · Answer 3 · answered Apr 09 '13 at 14:53

-1

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    // Call myMethod
    SecondController *controller = [[SecondController alloc] init];
    [controller myMethod:pt];
    [self.navigationController pushViewController:controller animated:YES];
    [controller release];
 }

The -release call is only necessary when you are not using ARC.

answered Apr 09 '13 at 14:53

cutsoy

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4
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This is wrong. The OP states that he created both controllers in the storyboard. Using alloc init will create a new instance rather than getting the one in the storyboard. – rdelmar Apr 09 '13 at 15:57

IOS: Call method in another controller

3 Answers3