【OC】Protocol

使用OC中的协议来实现一个按钮监听器

main.m
———————————
#import <Foundation/Foundation.h>
#import "Button.h"
#import "ButtonListener.h"
#import "MyListener.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //初始化一个Button按钮
        Button *btn = [[Button alloc] init];
        Button *btn2 = [[Button alloc] init];
        //初始化一个监听器
        //ButtonListener *listener = [[ButtonListener alloc] init];
        MyListener *listener2 = [[MyListener alloc] init];
        
        //btn.delegate = listener;
        //为按钮添加监听器
        btn.delegate = listener2;
        btn2.delegate = listener2;
        
        //按钮点击被触发
        [btn click];
        [btn2 click];
    }
    return 0;
}


Button.h
———————————————
#import <Foundation/Foundation.h>
@class Button;

// 设置按钮监听器的协议
@protocol ButtonDelegate <NSObject]]]]>
-(void) onClick:(Button *)btn;
@end


@interface Button : NSObject

@property (nonatomic, retain) id <ButtonDelegate> delegate;

-(void) click;

@end


Button.m
———————————————
#import "Button.h"

@implementation Button

-(void) dealloc{
    
    
}

//当触发惦记事件，调用该监听器的onclick方法，并将监听button传入进去
-(void)click{
    [_delegate onClick:self];
}

@end

MyListener.h
—————————————
#import <Foundation/Foundation.h>
@protocol ButtonDelegate;//作用相当于@class

//类ButtonListener实现ButtonDelegate协议
@interface MyListener : NSObject <ButtonDelegate]]]]>

@end

MyListener.m
————————————
#import "MyListener.h"
#import "Button.h"

@implementation MyListener

//实现协议中onClick方法，若不实现则报错
-(void)onClick:(Button *)btn{
    NSLog(@"监听器MyListener被触发-%@", btn);
}
@end