Question

我想使用委托将数据从视图控制器传输到第二个视图控制器。我正在做什么错，为什么我的协议没有在第二个视图控制器上确认。代码：

"This Is my view Controller code"

ViewController.h
#import <UIKit/UIKit.h>
#import "SecondViewController.h"

@protocol ViewControllerProtocol <NSObject>
-(void)passData:(NSString*)data;
@end

@interface ViewController : UIViewController

@property id<ViewControllerProtocol>delegateVC;
@property (weak, nonatomic) IBOutlet UITextField *txtFieldVC;
- (IBAction)btnSendVC:(id)sender;
@end


ViewController.m
#import "ViewController.h"

@interface ViewController ()
@end

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}
- (IBAction)btnSendVC:(id)sender {
    [self.delegateVC passData:self.txtFieldVC.text];
    [self performSegueWithIdentifier:@"next" sender:self];
}
@end//

"This is my second view Controller code"
SecondViewController.h
#import <UIKit/UIKit.h>
#import "ViewController.h"
@interface SecondViewController : UIViewController<ViewControllerProtocol>

- (IBAction)btnSVC:(id)sender;
@property (weak, nonatomic) IBOutlet UITextField *txtFieldSVC;
@end

//  SecondViewController.m

#import "SecondViewController.h"
@interface SecondViewController ()
@end

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

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
-(void)passData:(NSString *)data {
    self.txtFieldSVC.text = [NSString stringWithFormat:@"%@",data];
    NSLog(@"Data Received: %@",data);
}
- (IBAction)btnSVC:(id)sender {
    [self.navigationController popViewControllerAnimated:YES];
}
@end

我错了，我错过了什么......

Answer 1

如果我们使用上面的代码，就不可能使用Custom Delegate将数据从First View Controller发送到Second View Controller。但是如果我们想要将数据从Second View Controller发送到First View Controller，那么它是可能的。如果您希望将数据从Next View Controller发送到Previous View Controller，您可以使用自定义委托和通知方法来执行此操作。

现在您的要求是您必须将数据从First View Controller发送到Second View或Next View Controller。为此，您可以使用prepareForSegue和performSegueWithIdentifier方法进行故事板。这就足够了。

不重复我想在这里使用委托方法，因为我想使用委托将数据从视图控制器传输到另一个视图控制器

1 个答案: