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POCalling A Method With A Delegate in Objective-C (iOS)
 

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  1. POCalling A Method With A Delegate in Objective-C (iOS)
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    <p>I tried to replicade a couple of posts here on stackoverflow, for passing data and make calls with 2 view controllers, but without success.</p> <p>So I have my <strong>ViewController (1st)</strong> and <strong>EditableViewController (2nd)</strong></p> <p>When I'm in my <strong>EditableViewController (2nd)</strong>, I click a Button that triggers an IBAction with the method <strong>SendTextToViewController</strong>. After that, I was expecting for the method <strong>didReceiveMessage</strong>, in my <strong>ViewController (1st)</strong> to run, and show me "BANANAS" with NSLog.</p> <p>Ultimately, <strong>I want to send data from my second Controller, to the First Controller</strong>.</p> <p>I'm having a hard time understanding this delegates thing. And I have read a dozen tutorials, videos e documentation trying to figure this out. I think I'm almost there, but can't seem to figure why this is not working.</p> <p>Can anyone help me please? The code is bellow.</p> <p>Thank you!</p> <p><strong>// ViewController.h</strong></p> <pre><code>#import &lt;UIKit/UIKit.h&gt; @protocol ViewControllerDelegate &lt;NSObject&gt; -(void)didReceiveMessage:(NSString *)string; @end @interface ViewController : UIViewController &lt;ViewControllerDelegate&gt;; @end </code></pre> <p><strong>// ViewController.m</strong></p> <pre><code>#import "ViewController.h" @implementation ViewController -(void)didReceiveMessage:(NSString *)string{ NSLog(@"BANANAS"); } @end </code></pre> <p><strong>// EditableViewController.h</strong></p> <pre><code>#import &lt;UIKit/UIKit.h&gt; @protocol ViewControllerDelegate; @interface EditableViewController : UIViewController @property (nonatomic, weak) id&lt;ViewControllerDelegate&gt; delegate; @property (nonatomic, weak) IBOutlet UITextField *TextField; @property (nonatomic, weak) IBOutlet UIButton *SendTextToViewController; - (IBAction)SendTextToViewController:(id)sender; @end </code></pre> <p><strong>// EditableViewController.m</strong></p> <pre><code>#import "EditableViewController.h" #import "ViewController.h" @implementation EditableViewController @synthesize delegate; @synthesize TextField; @synthesize SendTextToViewController; - (IBAction)SendTextToViewController:(id)sender { [delegate didReceiveMessage:TextField.text]; } - (void)viewDidUnload { [self setTextField:nil]; [super viewDidUnload]; } @end </code></pre>
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    1. COTry loggging `delegate` in `(IBAction)SendTextToViewController:(id)sender` to check if your delegate is still there, it might get deallocated
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    2. COYou don't show anything in your code that sets the delegate variable to point to your view controller. Do you do that?
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      1. POCalling A Method With A Delegate in Objective-C (iOS)
      1. USPhillip Mills
    3. COSee Robert Vojta's answer. He's right, you did the opposite from what you should. Long story short, what you should do is populate your EditableViewController from your ViewController (1st) (navigation for example), and make your ViewController (1st) a delegate of your EditableViewController. And then when you click a button in EditableViewController, it sends a message to ViewController (1st) for the proper method call. I can provide more details if you need.
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      1. POCalling A Method With A Delegate in Objective-C (iOS)
      1. USRaymond Wang
 

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