iOS: Delegate action bar button to other class

Question

I have a UIViewController with a Container, and I have a UIBarButton on Navigation Bar, and I want the action of button go to the other class, the class of View1.

The class for the "Embed Segue" I don´t show because it is not need.

When I click the button nothing happens, not even the information in log (NSLog).

someone help me?

I have this:

//  ViewController.h
#import <UIKit/UIKit.h>

@protocol changeDelegate <NSObject>
-(void) changeLabel;
@end

@interface ViewController : UIViewController

@property (weak, nonatomic) id <changeDelegate> delegate;

@end


//  ViewController.m
#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
}

- (IBAction)changeButton:(UIBarButtonItem *)sender {

    [self.delegate changeLabel];

}

@end

//  Container.h

#import <UIKit/UIKit.h>

@interface Container : UIViewController

@end


//  Container.m

#import "Container.h"

@interface Container ()

@end

@implementation Container

- (void)viewDidLoad {
    [super viewDidLoad];

    [self performSegueWithIdentifier:@"segueView1" sender:nil];

}


- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

    [self addChildViewController:segue.destinationViewController];
    [self.view addSubview:((UIViewController *)segue.destinationViewController).view];

}

@end

//  View1.h

#import <UIKit/UIKit.h>

@interface View1 : UIViewController <changeDelegate>

@end


//  View1.m

#import "View1.h"

@interface View1 ()

@property (weak, nonatomic) IBOutlet UILabel *labelView1;

@end

@implementation View1

- (void)viewDidLoad {
    [super viewDidLoad];

}

-(void) changeLabel {
    NSLog(@"Button Action !");
    self.labelView1.text = @"Button Action !";
}

@end

Thanks, JProveta

Answer 1

I guess the problem is your delegate method is not firing. Try adding this in viewdidload of view.m

Viewcontroller *obj  = [[Viewcontroller alloc]init];
obj.delegate = self;

Answer 2

You see there's no call -(void) changeLabel , meanwhile ViewController don't know who it's delegate. You should assign the delegate for ViewController, in View1.m , you should have something like;

ViewController *vC = [ViewController new];
vC.delegate = self; // changeDelegate

Then

[self.delegate changeLabel];

is something like: [view1 changeLabel]; then the changeLabel was called.

---

For your project:

"ViewController.h" - (IBAction)changeButton:(UIBarButtonItem *)sender {

    [[NSNotificationCenter defaultCenter] postNotificationName:@"change_label_notfication" object:nil];

    //[self.delegate changeLabel];
    NSLog(@"button");

}

"View1.h"

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor redColor];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(changeLabel) name:@"change_label_notfication" object:nil];
}

Some suggestions:

1. ViewController's is controller of a view, so @interface View1 : UIViewController <changeDelegate> View1 is not a good name. 2.Not sure why you do in this way? But it's really a not good structure for you code. ViewController.h can set a label can controller properties, "Container.h" make no scene in your point.