使用'委托'在两个视图控制器之间传递数据：Objective-C [英] Pass Data between two view controllers using 'Delegation' : Objective-C

问题描述

我正在实现一个库（.a），我想将通知计数从库发送到应用程序，以便他们可以在其UI中显示通知计数。我要他们实现唯一的方法，如

   - （void）updateCount：（int）count {
 NSLog （@count * d，count）; 
} 
  

如何连续从我的图库发送计数， updateCount方法显示。
我搜索并了解回调函数。我不知道如何实现它们。

解决方案

您有3个选项

1. 委托


2. 通知


3. 阻止，也称为回叫

我想你想要的是Delegate

假设你有这个文件为lib

TestLib.h

  #import< Foundation / Foundation.h> 
 @protocol TestLibDelegate< NSObject> 
  - （void）updateCount：（int）count; 
 @end 
 
 @interface TestLib：NSObject 
 @property（weak，nonatomic）id< TestLibDelegate>代表; 
  - （void）startUpdatingCount; 
 @end 
  

TestLib.m

  #importTestLib.h
 
 @implementation TestLib 
  - （void）startUpdatingCount {
 int count = 0; / create count 
 if（[self.delegate respondingToSelector：@selector（updateCount :)]）{
 [self.delegate updateCount：count]; 
} 
} 
 @end 
  

想要使用

  #importViewController.h
 #importTestLib.h
 @ interface ViewController（）< TestLibDelegate> 
 @property（strong，nonatomic）TestLib * lib; 
 @end 
 
 @implementation ViewController 
  - （void）viewDidLoad {
 self.lib = [[TestLib alloc] init]; 
 self.lib.delegate = self; 
 [self.lib startUpdatingCount]; 
} 
  - （void）updateCount：（int）count {
 NSLog（@％d，count）; 
} 
 
 @end 
  

I am implementing an library(.a), and I want to send notification count from library to app so they can show in their UI, notification count. I want them to implement the only method like,

-(void)updateCount:(int)count{
    NSLog(@"count *d", count);
}

How can I send the count from my library continuously so they can use it in updateCount method to show. I searched and come to know about call back functions. I have no idea how to implement them. Is there any other way to do this.

解决方案

You have 3 options

1. Delegate
2. Notification
3. Block,also known callback

I think what you want is Delegate

Assume you have this file as lib

TestLib.h

#import <Foundation/Foundation.h>
@protocol TestLibDelegate<NSObject>
-(void)updateCount:(int)count;
@end

@interface TestLib : NSObject
@property(weak,nonatomic)id<TestLibDelegate> delegate;
-(void)startUpdatingCount;
@end

TestLib.m

#import "TestLib.h"

@implementation TestLib
-(void)startUpdatingCount{
    int count = 0;//Create count
    if ([self.delegate respondsToSelector:@selector(updateCount:)]) {
        [self.delegate updateCount:count];
    }
}
@end

Then in the class you want to use

#import "ViewController.h"
#import "TestLib.h"
@interface ViewController ()<TestLibDelegate>
@property (strong,nonatomic)TestLib * lib;
@end

@implementation ViewController
-(void)viewDidLoad{
self.lib = [[TestLib alloc] init];
self.lib.delegate = self;
[self.lib startUpdatingCount];
}
-(void)updateCount:(int)count{
    NSLog(@"%d",count);
}

@end

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