很多时候,开发的小伙伴需要反向传值,但是又不知道该怎么传,其实很简单,下面我简单介绍一下分别用block和delegate进行反向传值,希望能够帮到你们.

先附上github地址:https://github.com/ZSyingyu/BlockAndDelegateDemo.git

这些是在ZYYBankNameViewController里需要做的
1.利用block反向传值
要利用block反向传值,首先要声明一个block

typedef void(^bankNameBlock)(NSString *code,NSString *name);//block

同时还需要声明一个初始化方法

-(instancetype)initWithBankNameBlock:(bankNameBlock)block;//初始化方法

那么接下来我们就需要在.m中实现这个方法

-(instancetype)initWithBankNameBlock:(bankNameBlock)block {
    if (self == [super init]) {
        _block = block;
    }
    return self;
}

//block反向传值
NSDictionary *dic = self.bankArr[indexPath.row];
NSString *name = [[dic allKeys] firstObject];
NSString *code = [[dic allValues] firstObject];
if (_block) {
    _block(code,name);
}
[self.navigationController popViewControllerAnimated:YES];

2.利用delegate反向传值
同样的也需要先声明一个代理

@protocol BankNameDelegate <NSObject>//代理

-(void)popViewCode:(NSString *)code WithName:(NSString *)name;

@end

@property(nonatomic, weak)id<BankNameDelegate> delegate;//声明代理

接下来在.m中执行这个代理方法

//delegate回传值方法
NSDictionary *dic = self.bankArr[indexPath.row];
NSString *name = [[dic allKeys] firstObject];
NSString *code = [[dic allValues] firstObject];

[self.delegate popViewCode:code WithName:name];
[self.navigationController popViewControllerAnimated:YES];

在ZYYTestBlockViewController里就需要接收这些值了

//block回传值
ZYYBankNameViewController *bankNameVc = [[ZYYBankNameViewController alloc] initWithBankNameBlock:^(NSString *code, NSString *name) {
    NSLog(@"code:%@",code);
    NSLog(@"name:%@",name);
    NSString *nameCode = [NSString stringWithFormat:@"%@%@",name,code];
    [self.bankNameBtn setTitle:nameCode forState:UIControlStateNormal];
}];
[self.navigationController pushViewController:bankNameVc animated:YES];


//delegate回传值
ZYYBankNameViewController *bankNameVc = [[ZYYBankNameViewController alloc] init];
bankNameVc.delegate = self;
[self.navigationController pushViewController:bankNameVc animated:YES];

使用delegate反向传值的时候就需要执行代理方法了

#pragma mark - BankNameDelegate
-(void)popViewCode:(NSString *)code WithName:(NSString *)name {
    NSLog(@"code:%@",code);
    NSLog(@"name:%@",name);
    NSString *nameCode = [NSString stringWithFormat:@"%@%@",name,code];
    [self.bankNameBtn setTitle:nameCode forState:UIControlStateNormal];

}

原理很简单,可能写的比较乱,因为我们比较让人蛋疼的产品一直在我旁边说需求,所以对不住大家了,可以配合着demo来看,如果有看不明白的欢迎留言,我会尽快回复的.