Ios 将数据从委托视图发送到委托视图[Objective-C]

因此，我试图学习如何将数据从一个视图控制器发送到另一个视图控制器

到目前为止，我的代码获取从一个VC（

DelegateVC

）输入的数据，并将其显示在另一个VC（

ViewController

）上的标签中

这里的委托是

ViewController

，委托是

DelegateVC

===========================================================================

主要问题 但是如果我想将标签数据从

ViewController

传递到

DelegateVC

，该怎么办？我怎样才能做到这一点？我尝试设计相同的委托概念，但使用

DelegateVC

作为

ViewController

的委托。不确定这是否是写方法

TL；博士： 在

VC

中，如果我点击

Next View

，我将进入

DelegateVC

并输入“test”，它将在

VC的接收标签中显示为“test”

现在，下次点击
next View
，我希望现有标签的值显示在
DelegateVC
的
TextField
中。不是空白的
文本字段
，而是值“test”

===========================================================================
假设我有一个
Main.storyboard
像这样：


我有一个
ViewController.h
文件：

#import <UIKit/UIKit.h>
@interface ViewController : UIViewController


@end

DelegateVC.h:

#import <UIKit/UIKit.h>
@protocol MainVCDelegate;

@interface DelegatedVC : UIViewController
@property (strong, nonatomic) IBOutlet UITextField *sendDataTF;
- (IBAction)sendData:(id)sender;
@property (weak, nonatomic) id<MainVCDelegate> delegate;
@end

@protocol MainVCDelegate <NSObject>
-(void) sendBackData: (DelegatedVC *) delegatedVC : (NSString *) textField;
@end

#import "DelegatedVC.h"
@protocol MainVCDelegate;

@interface DelegatedVC ()

@end

@implementation DelegatedVC

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

- (IBAction)sendData:(id)sender {
    [self.delegate sendBackData: self : _sendDataTF.text];
}
@end

但是如果我想从ViewController传递标签的数据呢
授权VC？我怎样才能做到这一点

因此，正如我在代码中看到的那样，您的委托是正确的。回到您的主要问题，您只需要在
DelegateVC.h
中声明一个公共
NSString
对象，然后访问该对象并将数据从
ViewController
的
prepareforsgue
传递到该对象

下一步，在
DelegateVC.m
中，获取
NSString
对象的值并将其传递给
UITextField

如果有帮助，请告诉我：）

但是如果我想从ViewController传递标签的数据呢
授权VC？我怎样才能做到这一点

因此，正如我在代码中看到的那样，您的委托是正确的。回到您的主要问题，您只需要在
DelegateVC.h
中声明一个公共
NSString
对象，然后访问该对象并将数据从
ViewController
的
prepareforsgue
传递到该对象

下一步，在
DelegateVC.m
中，获取
NSString
对象的值并将其传递给
UITextField

让我知道这是否有帮助：）
代理允许一个对象在事件发生时向另一个对象发送消息

如果要将标签数据从
ViewController
传递到
DelegateVC
，则不需要使用delegate。但是，由于在
sendDataTF
textfield上发生更改时，您希望更新
receivingLabel
，因此在这种情况下，您需要一个代理，我认为您已经做得很好了

解决方案：您需要在
DelegateVC
中声明一个属性来存储从
ViewController
传递的字符串，并在
viewDidLoad
上的
sendDataTF
中设置该文本

在DelegateVC.h中声明属性：

#import "ViewController.h"
#import "DelegatedVC.h"

@interface ViewController () <MainVCDelegate>
@property (strong, nonatomic) IBOutlet UILabel *receivingLabel;
- (IBAction)nextView:(id)sender;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (IBAction)nextView:(id)sender {

}

-(void) sendBackData:(DelegatedVC *)delegatedVC :(NSString *)textField {
    [delegatedVC dismissViewControllerAnimated:YES completion:nil];
    self.receivingLabel.text = textField;
}
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    DelegatedVC *secondVC = segue.destinationViewController;
    secondVC.delegate = self;
}
@end

@interface DelegatedVC : UIViewController

@property (weak, nonatomic) id<MainVCDelegate> delegate;
@property (strong, nonatomic) NSString *labelString;

@property (strong, nonatomic) IBOutlet UITextField *sendDataTF;

- (IBAction)sendData:(id)sender;

@end

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender           
{
   DelegatedVC *secondVC = segue.destinationViewController;
   secondVC.delegate = self;
   secondVC.labelString = self.receivingLabel.text;
}

- (void)viewDidLoad {
  [super viewDidLoad];
  self.sendDataTF.text = self.labelString;
}

在DelegateVC.m:

#import "ViewController.h"
#import "DelegatedVC.h"

@interface ViewController () <MainVCDelegate>
@property (strong, nonatomic) IBOutlet UILabel *receivingLabel;
- (IBAction)nextView:(id)sender;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (IBAction)nextView:(id)sender {

}

-(void) sendBackData:(DelegatedVC *)delegatedVC :(NSString *)textField {
    [delegatedVC dismissViewControllerAnimated:YES completion:nil];
    self.receivingLabel.text = textField;
}
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    DelegatedVC *secondVC = segue.destinationViewController;
    secondVC.delegate = self;
}
@end

@interface DelegatedVC : UIViewController

@property (weak, nonatomic) id<MainVCDelegate> delegate;
@property (strong, nonatomic) NSString *labelString;

@property (strong, nonatomic) IBOutlet UITextField *sendDataTF;

- (IBAction)sendData:(id)sender;

@end

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender           
{
   DelegatedVC *secondVC = segue.destinationViewController;
   secondVC.delegate = self;
   secondVC.labelString = self.receivingLabel.text;
}

- (void)viewDidLoad {
  [super viewDidLoad];
  self.sendDataTF.text = self.labelString;
}

希望它能工作。
委托允许一个对象在事件发生时向另一个对象发送消息

如果要将标签数据从
ViewController
传递到
DelegateVC
，则不需要使用delegate。但是，由于在
sendDataTF
textfield上发生更改时，您希望更新
receivingLabel
，因此在这种情况下，您需要一个代理，我认为您已经做得很好了

解决方案：您需要在
DelegateVC
中声明一个属性来存储从
ViewController
传递的字符串，并在
viewDidLoad
上的
sendDataTF
中设置该文本

在DelegateVC.h中声明属性：

#import "ViewController.h"
#import "DelegatedVC.h"

@interface ViewController () <MainVCDelegate>
@property (strong, nonatomic) IBOutlet UILabel *receivingLabel;
- (IBAction)nextView:(id)sender;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (IBAction)nextView:(id)sender {

}

-(void) sendBackData:(DelegatedVC *)delegatedVC :(NSString *)textField {
    [delegatedVC dismissViewControllerAnimated:YES completion:nil];
    self.receivingLabel.text = textField;
}
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    DelegatedVC *secondVC = segue.destinationViewController;
    secondVC.delegate = self;
}
@end

@interface DelegatedVC : UIViewController

@property (weak, nonatomic) id<MainVCDelegate> delegate;
@property (strong, nonatomic) NSString *labelString;

@property (strong, nonatomic) IBOutlet UITextField *sendDataTF;

- (IBAction)sendData:(id)sender;

@end

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender           
{
   DelegatedVC *secondVC = segue.destinationViewController;
   secondVC.delegate = self;
   secondVC.labelString = self.receivingLabel.text;
}

- (void)viewDidLoad {
  [super viewDidLoad];
  self.sendDataTF.text = self.labelString;
}

在DelegateVC.m:

#import "ViewController.h"
#import "DelegatedVC.h"

@interface ViewController () <MainVCDelegate>
@property (strong, nonatomic) IBOutlet UILabel *receivingLabel;
- (IBAction)nextView:(id)sender;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (IBAction)nextView:(id)sender {

}

-(void) sendBackData:(DelegatedVC *)delegatedVC :(NSString *)textField {
    [delegatedVC dismissViewControllerAnimated:YES completion:nil];
    self.receivingLabel.text = textField;
}
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    DelegatedVC *secondVC = segue.destinationViewController;
    secondVC.delegate = self;
}
@end

@interface DelegatedVC : UIViewController

@property (weak, nonatomic) id<MainVCDelegate> delegate;
@property (strong, nonatomic) NSString *labelString;

@property (strong, nonatomic) IBOutlet UITextField *sendDataTF;

- (IBAction)sendData:(id)sender;

@end

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender           
{
   DelegatedVC *secondVC = segue.destinationViewController;
   secondVC.delegate = self;
   secondVC.labelString = self.receivingLabel.text;
}

- (void)viewDidLoad {
  [super viewDidLoad];
  self.sendDataTF.text = self.labelString;
}

希望它能工作。
以下是正确的工作代码，您可以查看：

带有标签和按钮的DelegateVc.h文件

#import <UIKit/UIKit.h>
#import "DelegatedVC.h"

@interface DelegateVC : UIViewController
@property (weak, nonatomic) IBOutlet UILabel *ReceiveLabel;
@property (weak, nonatomic) IBOutlet UIButton *NextView;
@property (strong, nonatomic) NSString *TextFeildText;

带文本字段的DelagatedVc.h

#import <UIKit/UIKit.h>
#import "DelegateVC.h"

@interface DelegatedVC : UIViewController
@property (weak, nonatomic) IBOutlet UITextField *RCTextField;
@property (weak, nonatomic) IBOutlet UIButton *SenddataBtn;
@property (strong, nonatomic) NSString *LabelText;
@end

我的故事板前景

以下是您可以查看的正确工作代码：

带有标签和按钮的DelegateVc.h文件

#import <UIKit/UIKit.h>
#import "DelegatedVC.h"

@interface DelegateVC : UIViewController
@property (weak, nonatomic) IBOutlet UILabel *ReceiveLabel;
@property (weak, nonatomic) IBOutlet UIButton *NextView;
@property (strong, nonatomic) NSString *TextFeildText;

带文本字段的DelagatedVc.h

#import <UIKit/UIKit.h>
#import "DelegateVC.h"

@interface DelegatedVC : UIViewController
@property (weak, nonatomic) IBOutlet UITextField *RCTextField;
@property (weak, nonatomic) IBOutlet UIButton *SenddataBtn;
@property (strong, nonatomic) NSString *LabelText;
@end

我的故事板前景

与其使用一个序列返回到原始视图控制器，不如使用一个展开序列，这样您的视图就不会彼此重叠。与其使用分段返回到原始视图控制器，不如使用展开分段，这样您的视图就不会彼此重叠。我试过了，但没用。我所做的是在
DelegateVC.h
声明的
静态NSString*globalStr
中。在
ViewController
的
prepareforsgue
中，我添加了
globalStr=\u receivingLabel.text
。最后，在DelegateVC.m的viewdiload中，我添加了sendDataTF.text=globalStr

。思想？谢谢这就是我在上面的回答中告诉你的：）我试过了，但没有成功。我所做的是在

DelegateVC.h

声明的

静态NSString*globalStr

中。在

ViewController

的

prepareforsgue

中，我添加了

globalStr=\u receivingLabel.text

。最后，在DelegateVC.m的viewdiload中，我添加了sendDataTF.text=globalStr。思想？谢谢这就是我在上面的回答中告诉你的：）