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.
