一、代理传值的方法

　　1.Hehe1ViewController.h中

#import <UIKit/UIKit.h>

@protocol Hehe1ViewControllerDelegate <NSObject>

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

@end

@interface Hehe1ViewController : UIViewController

@property(nonatomic,weak) id delegate;

@end

　　2.Hehe1ViewController.m中

#import "Hehe1ViewController.h"

@interface Hehe1ViewController ()

@property(nonatomic,strong) UITextField *heheTextField;

@end

@implementation Hehe1ViewController

- (void)viewDidLoad {

[super viewDidLoad];

UITextField *heheTextField = [[UITextField alloc] initWithFrame:CGRectMake(20, 200, 300, 40)];

self.heheTextField = heheTextField;

heheTextField.backgroundColor = [UIColor lightGrayColor];

[self.view addSubview:heheTextField];

UIButton *button1 = [UIButton buttonWithType:UIButtonTypeSystem];

button1.frame = CGRectMake(20, 250, 300, 50);

button1.backgroundColor = [UIColor orangeColor];

[button1 setTitle:@"Back to VC" forState:UIControlStateNormal];

[button1 setTintColor:[UIColor whiteColor]];

[button1 addTarget:self action:@selector(goToHehe1) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button1];

}

- (void)goToHehe1 {

NSLog(@"hehe1...");

[_delegate backValueWith:self.heheTextField.text];

[self.navigationController popViewControllerAnimated:YES];

}

@end

　　二、block传值

　　1.Hehe2ViewController.h中

#import <UIKit/UIKit.h>

typedef void(^BackValue)(NSString *str);

@interface Hehe2ViewController : UIViewController

@property(nonatomic,copy) BackValue backValue;

- (void)returnStr:(BackValue)block;

@end

　　2.Hehe2ViewController.m中

#import "Hehe2ViewController.h"

@interface Hehe2ViewController ()

@property(nonatomic,strong) UITextField *heheTextField;

@end

@implementation Hehe2ViewController

- (void)viewDidLoad {

[super viewDidLoad];

UITextField *heheTextField = [[UITextField alloc] initWithFrame:CGRectMake(20, 200, 300, 40)];

self.heheTextField = heheTextField;

heheTextField.backgroundColor = [UIColor lightGrayColor];

[self.view addSubview:heheTextField];

UIButton *button2 = [UIButton buttonWithType:UIButtonTypeSystem];

button2.frame = CGRectMake(20, 250, 300, 50);

button2.backgroundColor = [UIColor orangeColor];

[button2 setTitle:@"Back to VC" forState:UIControlStateNormal];

[button2 setTintColor:[UIColor whiteColor]];

[button2 addTarget:self action:@selector(goToHehe2) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button2];

}

- (void)returnStr:(BackValue)block {

self.backValue = block;

}

- (void)goToHehe2 {

NSLog(@"hehe2...");

self.backValue(self.heheTextField.text);

[self.navigationController popViewControllerAnimated:YES];

}

@end

　　三、在ViewController.m中接收传回的值

#import "ViewController.h"

#import "Hehe1ViewController.h"　　//delegate

#import "Hehe2ViewController.h"　　//block

#define klSceenWidth self.view.bounds.size.width

@interface ViewController ()

@property(nonatomic,strong) UILabel *label1;

@property(nonatomic,strong) UILabel *label2;

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

UILabel *label1 = [[UILabel alloc] initWithFrame:CGRectMake(20, 100, klSceenWidth-40, 30)];

self.label1 = label1;

[self.view addSubview:label1];

　 //delegate

UIButton *button1 = [UIButton buttonWithType:UIButtonTypeSystem];

button1.frame = CGRectMake(20, 150, klSceenWidth-40, 30);

button1.backgroundColor = [UIColor orangeColor];

[button1 setTitle:@"go to hehe1" forState:UIControlStateNormal];

[button1 setTintColor:[UIColor whiteColor]];

[button1 addTarget:self action:@selector(goToHehe1) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button1];

　　//block

UILabel *label2 = [[UILabel alloc] initWithFrame:CGRectMake(20, 200, klSceenWidth-40, 30)];

self.label2 = label2;

[self.view addSubview:label2];

UIButton *button2 = [UIButton buttonWithType:UIButtonTypeSystem];

button2.frame = CGRectMake(20, 250, klSceenWidth-40, 30);

button2.backgroundColor = [UIColor orangeColor];

[button2 setTitle:@"go to hehe1" forState:UIControlStateNormal];

[button2 setTintColor:[UIColor whiteColor]];

[button2 addTarget:self action:@selector(goToHehe2) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button2];

}

- (void)backValueWith:(NSString*)str {

self.label1.text = str;

}

- (void)goToHehe1 {

Hehe1ViewController *heheVC1= [[Hehe1ViewController alloc] init];

heheVC1.delegate = self;

[self.navigationController pushViewController:heheVC1 animated:YES];

}

- (void)goToHehe2 {

Hehe2ViewController *heheVC2= [[Hehe2ViewController alloc] init];

[heheVC2 returnStr:^(NSString *str) {

self.label2.text = str;

}];

[self.navigationController pushViewController:heheVC2 animated:YES];

}

@end