iOS--页面间的代理传值(属性、代理(委托)、代码块、单例、通知)

时间:2021-02-28 05:06:27

(一)属性传值

(二)代理(委托)传值


代理传值
适用于 反向传值 (从后往前传)
1.1 创建协议 及协议方法 在反向传值的页面(SecondViewController)中
1.2 创建协议类型的属性 在SecondViewController中创建属性id<postValueDelegate> delegate
1.3 调用属性 即delegate
在SecondViewController页面中 对象传值的方法中调用
[self.delegate postValue:self.textName.text];
1.4 在第一页 即显示修改过信息的页面
遵循协议 实现协议方法 指定代理对象(即 在页面传值参数的方法中为代理赋值)
secondVc.delegate=self;

文件目录:

iOS--页面间的代理传值(属性、代理(委托)、代码块、单例、通知)

FirstViewController.h

#import <UIKit/UIKit.h>
#import "SecondViewController.h"
@interface FirstViewController : UIViewController<UITextFieldDelegate,postValue> @property(strong,nonatomic) UITextField *textName;
@property(strong,nonatomic) UIButton *nextbutton; @end

FirstViewController.m

#import "FirstViewController.h"

@interface FirstViewController ()

@end

@implementation FirstViewController

- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor=[UIColor redColor];
self.textName=[[UITextField alloc] initWithFrame:CGRectMake(, , ,)];
self.textName.borderStyle=UITextBorderStyleLine;
self.textName.delegate=self;
[self.view addSubview:self.textName]; self.nextbutton=[[UIButton alloc] initWithFrame:CGRectMake(, , , )];
[self.nextbutton setTitle:@"下一页" forState:UIControlStateNormal];
self.nextbutton.backgroundColor=[UIColor grayColor];
[self.nextbutton addTarget:self action:@selector(nextPage) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.nextbutton]; } -(BOOL)textFieldShouldReturn:(UITextField *)textField
{
if ([textField isFirstResponder]) {
[textField resignFirstResponder];
} return YES;
} -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
[self.textName resignFirstResponder];
} -(void)nextPage
{
SecondViewController *secondVc=[[SecondViewController alloc] init];
secondVc.str=self.textName.text;
secondVc.deletage=self;
[self presentViewController:secondVc animated:YES completion:nil];
} -(void)postValue:(NSString *)str
{
self.textName.text=str;
} - (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
} @end

SecondViewController.h

#import <UIKit/UIKit.h>

// 创建协议

@protocol postValue <NSObject>

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

@end

@interface SecondViewController : UIViewController<UITextFieldDelegate>

@property(strong,nonatomic) UITextField *textInfo;
@property(strong,nonatomic) UIButton *backbutton;
@property(strong,nonatomic) NSString *str; @property(strong,nonatomic) id<postValue> deletage; @end

SecondViewController.m

#import "SecondViewController.h"

@interface SecondViewController ()

@end

@implementation SecondViewController

- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor=[UIColor colorWithRed:0.541 green:0.878 blue:0.831 alpha:1.000]; self.textInfo=[[UITextField alloc] initWithFrame:CGRectMake(, , , )];
self.textInfo.borderStyle=UITextBorderStyleLine;
self.textInfo.text=self.str;
self.textInfo.delegate=self; [self.view addSubview:self.textInfo]; self.backbutton=[[UIButton alloc] initWithFrame:CGRectMake(, , , )];
[self.backbutton setTitle:@"上一页" forState:UIControlStateNormal];
self.textInfo.text=self.str;
[self.backbutton addTarget:self action:@selector(backPage) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.backbutton]; } -(BOOL)textFieldShouldReturn:(UITextField *)textField
{
if ([textField isFirstResponder]) {
[textField resignFirstResponder];
} return YES;
} -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
[self.textInfo resignFirstResponder];
} -(void)backPage
{
if (self.deletage!=) {
[self.deletage postValue:self.textInfo.text];
} [self dismissViewControllerAnimated:YES completion:nil];
} - (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end

AppDelegate.h

#import <UIKit/UIKit.h>
#import"FirstViewController.h"
@interface AppDelegate : UIResponder <UIApplicationDelegate> @property (strong, nonatomic) UIWindow *window; @end

AppDelegate.m

#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
FirstViewController *firstVc=[[FirstViewController alloc] init]; self.window.rootViewController=firstVc; return YES;
}
.......

@end

(三)代码块传值

(四)通知传值

(五)单例传值