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所以我有3个视图如下：viewController >> viewController2 >> viewController3。在 viewController3 中，我创建了一个委托协议。协议方法是打印出 NSLog 的简单方法。

当我从 ViewController3 调用委托时，只有其父 (viewController2) 不响应（第一个）viewController。没有错误。我认为问题与 [v2 setDelegate:self]; 在 viewController.m 文件中。尽管如此，[self.v3 setDelegate:self]; 在 ViewController2.m 文件中工作正常。

为什么（第一个）viewController 委托没有响应？代表只与它的直系孩子一起工作吗？

> **ViewController.h**
   #import <UIKit/UIKit.h>
   #import "ViewController2.h"
   #import "ViewController2.h"
   @interface ViewController : UIViewController <PassData>{

    ViewController2 *v2;
   }
   @property (strong, nonatomic) ViewController2 *v2;

> Blockquote

    - (IBAction)button:(id)sender;
    @end

> **ViewController.M**

    #import "ViewController.h"

   @interface ViewController ()

   @end

   @implementation ViewController
   @synthesize v2;

    - (IBAction)button:(id)sender {

    v2 = [[ViewController2 alloc]initWithNibName:@"ViewController2" bundle:nil];
    [v2 setDelegate:self];
    [self.view addSubview:v2.view];
    }

    -(void)print: (BOOL)success;{

    if (success == YES) {
        NSLog(@"ViewController called");
    }

    }

    @end

> > ViewController2.h

   #import <UIKit/UIKit.h>
   #import "ViewController3.h"

    @interface ViewController2 : UIViewController <PassData> {

    ViewController3 *v3;

     }
     @property (strong, nonatomic)ViewController3 *v3;
     @property (retain) id delegate;

   - (IBAction)button:(id)sender;
     @end

   ViewController2.m

   #import "ViewController2.h"

    @interface ViewController2 ()

     @end

    @implementation ViewController2
   @synthesize v3,delegate;

     - (IBAction)button:(id)sender {

    v3 = [[ViewController3 alloc]initWithNibName:@"ViewController3" bundle:nil];
    [self.v3 setDelegate:self];
    [self.view addSubview:v3.view];

     }

    -(void)print: (BOOL)success;{

    if (success == YES) {
          NSLog(@"ViewController2 called");
    }
    }
     @end

> ViewController3.h

   #import <UIKit/UIKit.h>

    @protocol PassData <NSObject>

    @required

    -(void)print:(BOOL)success;

    @end

    @interface ViewController3 : UIViewController {

    id<PassData>  delegate;

     }

    @property (retain) id delegate;

   - (IBAction)callButton:(id)sender;

    @end

     ViewController3.m

    #import "ViewController3.h"

    @interface ViewController3 ()

    @end

    @implementation ViewController3
    @synthesize delegate;

    - (IBAction)callButton:(id)sender {

    // call all delegates
      [[self delegate]print:YES];

     }
    @end
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1 回答 1

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v2 没有方法“print”，这是 v3 的协议方法——你不能像这样链接委托消息。如果您希望多个控制器响应另一个控制器中的某些内容，那么您应该使用 NSNotification——任何数量的对象都可以注册以接收通知。

于 2013-01-23T17:08:26.277 回答