关于iOS 中得block传值问题献给新手

//关于block传值类似与代理传值,而block的优点就是不用繁琐的定义委托代理,下面是我写得一个小demo,献给学习block新手<img alt="微笑" src="http://static.blog.youkuaiyun.com/xheditor/xheditor_emot/default/smile.gif" />,一起学习讨论哈,望大神们不吝赐教

<pre name="code" class="objc">#import <UIKit/UIKit.h>
#import "PushViewController.h"
@interface RootViewController : UIViewController
@property(nonatomic,retain)UITextField * textfield;
/**
 *  设置控制器的属性来传值
 */
@property(nonatomic,retain)PushViewController * push;
@end

#import "RootViewController.h"
#import "PushViewController.h"
@interface RootViewController ()

@end

@implementation RootViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.navigationItem.title =@"RootViewController.h";
    /**
     *  创建接收控件
     */
    UITextField * textField = [[UITextField alloc]initWithFrame:CGRectMake(50, 200, 220, 40)];
    self.textfield =textField;
    textField.backgroundColor = [UIColor redColor];
    [self.view addSubview:textField];
    //push按钮
    UIButton * push = [UIButton buttonWithType:UIButtonTypeCustom];
    push.frame = CGRectMake(100, 300, 120, 50);
    [push setTitle:@"push" forState:UIControlStateNormal];
    [push addTarget:self action:@selector(push:) forControlEvents:UIControlEventTouchUpInside];
    push.backgroundColor = [UIColor greenColor];
    [self.view addSubview:push];
    _push = [[PushViewController alloc]init];
    __block UITextField * text = self.textfield;
    /**
     *  实现要把值传给的控件
     */
    _push.traditionalBlock = ^(NSString * string){
        text.text = string;
    };
    
}
//push事件
-(void)push:(UIButton *)sender
{
    [self.navigationController pushViewController:_push animated:YES];
}
@end

#import <UIKit/UIKit.h>
/**
 *  定义block
 */
typedef void(^TraditionalBlock)(NSString *);

@interface PushViewController : UIViewController

@property(nonatomic,retain)UITextField * textfield;
/**
 *  声明一个block属性
 */
@property(nonatomic,copy)TraditionalBlock traditionalBlock ;

#import "PushViewController.h"

@interface PushViewController ()

@end

@implementation PushViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.navigationItem.title =@"PushViewController.h";

//创建一个控件来接受值
    UITextField * textField = [[UITextField alloc]initWithFrame:CGRectMake(50, 200, 220, 40)];
    self.textfield =textField;
    textField.backgroundColor = [UIColor orangeColor];
    [self.view addSubview:textField];
    
//pop按钮
    UIButton * pop = [UIButton buttonWithType:UIButtonTypeCustom];
    pop.frame = CGRectMake(100, 300, 120, 50);
    [pop addTarget:self action:@selector(pop:) forControlEvents:UIControlEventTouchUpInside];
    [pop setTitle:@"传值" forState:UIControlStateNormal];
    pop.backgroundColor = [UIColor greenColor];
    [self.view addSubview:pop];
}
/**
 *  pop事件
 */
-(void)pop:(UIButton *)sender
{
    /**
     *  实现block方法以及自己要传得值
     */
    _traditionalBlock(_textfield.text);
    [self.navigationController popViewControllerAnimated:YES];
}