iOS 协议的继承

今天看了一个pdf文档,了解到了 协议的继承,特别做了个小demo测试了一下,下面是代码

OneDelegate.h

@protocol OneDelegate 

@required

- (void)backStr:(NSString *)str;

@end

@protocol TwoDelegate 

@optional

- (void)backInt:(int)i;

@end

#import "ViewController2.h"

@interface ViewController : UIViewController 

@end

- (void)viewDidLoad
{
    [super viewDidLoad];
	
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(50, 50, 200, 100);
    button.backgroundColor = [UIColor yellowColor];
    [button setTitle:@"into VC2" forState:UIControlStateNormal];
    [button addTarget:self action:@selector(push) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    
}

- (void)push{
    ViewController2 *vc = [[ViewController2 alloc]init];
    vc.delegate = self;
    [self presentViewController:vc animated:YES completion:^{
    
    }];
}

//OneDelegate
- (void)backStr:(NSString *)str{
    NSLog(@"%@",str);
}

//TwoDelegate
- (void)backInt:(int)i{
    NSLog(@"%d",i);
}

#import 
#import "two.h"

@interface ViewController2 : UIViewController

@property(nonatomic ,unsafe_unretained)id delegate;

@end

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    
	UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(50, 50, 200, 100);
    button.backgroundColor = [UIColor yellowColor];
    [button addTarget:self action:@selector(backStrBtn) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    
    UIButton *button2 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button2.frame = CGRectMake(50, 200, 200, 100);
    button2.backgroundColor = [UIColor blueColor];
    [button2 addTarget:self action:@selector(backIntBtn) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button2];
}

- (void)backStrBtn{
    if (self.delegate && [self.delegate respondsToSelector:@selector(backStr:)]) {
        [self.delegate backStr:@"这个是代理1的方法"];
    }
}

- (void)backIntBtn{
    if (self.delegate && [self.delegate respondsToSelector:@selector(backInt:)]) {
        [self.delegate backInt:2];
        NSLog(@"这是继承的方法");
    }
}