从控制器secondViewController(简称B)传给ViewController(简称A)
总结：block和delegate都可以实现逆向传参数，区别：
delegate的流程是：B定义协议内容 A添加代理并实现B的协议
但block 实现在block里面，A中只要写个B.block赋值
备注：顺向传参：一般使用property参数或重写init
一. Block实现：
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//控制器ViewController.m
#import"ViewController.h"
#import"secondViewController.h"
@interfaceViewController(){
__weakIBOutletUILabel*m_label1;
__weakIBOutletUILabel*m_label2;
}
- (IBAction)btnAction:(UIButton*)sender {
UIStoryboard*story = [UIStoryboardstoryboardWithName:@"Main"bundle:nil];
secondViewController*vc = [storyinstantiateViewControllerWithIdentifier:@"secondVC"];
//添加secondViewController的两个block
vc.mm_block= ^(NSString* name,NSString* age){
//bock回调的参数，传递成功
NSLog(@"－－－%@－－－－",name);
m_label1.text= [NSStringstringWithFormat:@"%@ age is %@",name,age];
};
vc.sBlock= ^(NSString*m_city){
//bock回调的参数，传递成功
m_label2.text= [NSStringstringWithFormat:@"city: %@",m_city];
NSLog(@"－－－%@－－－－",m_city);
};
[selfpresentViewController:vcanimated:YEScompletion:nil];
}
------------------------------------------
//控制器secondViewController.h
#import
#import"ViewController.h"
typedefvoid(^cBlock)(NSString*x,NSString*y);//使用typedef可创建多个此block使用
@interfacesecondViewController : UIViewController
@property(nonatomic,strong) cBlock mm_block;//声明block
@property(nonatomic,strong)void(^sBlock)(NSString* city);//声明block
@end
//控制器secondViewController.m
- (IBAction)returnSuperVc:(id)sender {
[self dismissViewControllerAnimated:YES completion:^(){
//判断block是否存在
if (_mm_block) {
_mm_block(@"caicai",@"18"); //赋值 调用block
}
//判断block是否存在
if (_sBlock) {
_sBlock(@"shenzhen");//赋值 调用block
}
}];
}
二. delegate实现
－－－－－－－－－－
//控制器secondViewController.h
#import
#import"ViewController.h"
//定义协议
@protocolsecondViewDelegate
-(void)secondView:(NSString* )name age:(NSString*)age;
@end
@interfacesecondViewController :UIViewController
@property(nonatomic,weak)id delegate;//声明代理
@end
//控制器secondViewController.m
- (IBAction)returnSuperVc:(id)sender {
[selfdismissViewControllerAnimated:YEScompletion:^(){
//判断代理是否存在
if(_delegate) {
[_delegatesecondView:@"caicai"age:@"18"];//代理传参
}
}];
}
------------------------------------------
//控制器ViewController.h
#import
#import"secondViewController.h"
@interfaceViewController :UIViewController//添加代理
@end
------------------------------------------
//控制器ViewController.m
- (IBAction)btnAction:(UIButton*)sender {
UIStoryboard*story = [UIStoryboardstoryboardWithName:@"Main"bundle:nil];
secondViewController*vc = [storyinstantiateViewControllerWithIdentifier:@"secondVC"];
vc.delegate=self; //添加代理
[selfpresentViewController:vcanimated:YEScompletion:nil];
}
#pragma mark secondViewDelegate
-(void)secondViewDelegate:(NSString* )name age:(NSString*)age{
//delegate回调的参数，传递成功
NSLog(@"－－－%@－－－－",name);
m_label1.text= [NSStringstringWithFormat:@"%@ age is %@",name,age];
}
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