本文主要介紹在不同的檢視控制器之間進行傳值，分為兩種傳值方式，正向傳值比較容易，逆向傳值相對於正向來說麻煩一點，需要使用代理或者是block

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITextField *textField1;
@property (weak, nonatomic) IBOutlet UITextField *textField2;
@end
 

- (IBAction)presentViewController:(id)sender
{
    // 在storyboard中設定secondViewController的identifier為123
    SecondViewController *secondVc = [self.storyboard instantiateViewControllerWithIdentifier:@"123"];
    // 關於傳值的程式碼
    secondVc.data1 = self.textField1.text;
    secondVc.data2 = self.textField2.text;
    // 注意在這裡不能夠直接給第二個檢視控制器的lable賦值,例如下面的程式碼就是不正確的
#if 0
    secondVc.lable1.text = self.textField1.text;
    secondVc.lable2.text = self.textField2.text;
#endif
    // 進行跳轉
    [self presentViewController:secondVc animated:YES completion:nil];
}
 

@property (nonatomic, strong) NSString *data1;
@property (nonatomic, strong) NSString *data2;
@property (weak, nonatomic) IBOutlet UILabel *lable1;
@property (weak, nonatomic) IBOutlet UILabel *lable2;

- (IBAction)presentToSecondVIewController:(id)sender
{
    SecondViewController *secondVc = [self.storyboard instantiateViewControllerWithIdentifier:@"123"];
    // 將自己設定為第二個檢視控制器的代理物件
    secondVc.delegate = self;
    [self presentViewController:secondVc animated:YES completion:nil];
}
 

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:YES];
    self.lable1.text = self.data1;
    self.lable2.text = self.data2;
}

@property (weak, nonatomic) IBOutlet UILabel *lable;

- (IBAction)presentToSecondVIewController:(id)sender
{
    // 在storyboard中將第二個檢視控制器的identifier設定為了123
    SecondViewController *secondVc = [self.storyboard instantiateViewControllerWithIdentifier:@"123"];
    // 將自己設定為第二個檢視控制器的代理物件
    secondVc.delegate = self;
    [self presentViewController:secondVc animated:YES completion:nil];
}

#pragma mark - 第二個檢視控制器的代理方法
- (void)passValue:(NSString *)lableText
{
    self.lable.text = lableText;
}

// 1、宣告協議
@protocol SecondViewControllerDelegate <NSObject>
@optional
// 2、協議的方法
- (void)passValue :(NSString *)lableText;
@end

@interface SecondViewController : ViewController
// 3、定義協議屬性
@property (nonatomic,weak)id<SecondViewControllerDelegate> delegate;

- (IBAction)dissmissBackToVIewController:(id)sender
{
    // 判斷這個協議方法是否被實現
    if ([self.delegate respondsToSelector:@selector(passValue:)]) {
        // 如果實現了就將第二個檢視控制器中lable的值給傳到代理方法中，使得第一個類在實現代理方法的時候可以能夠或者這個值（這個值在實現代理方法的時候就是方法的引數lableText）
        [self.delegate passValue:self.lable.text];
    }
    // 跳轉會第一個檢視控制器
    [self dismissViewControllerAnimated:YES completion:nil];
}

@property (weak, nonatomic) IBOutlet UILabel *lable;

- (IBAction)tureToSecondVc:(id)sender
{
    // 在storyboard裡面設定第二個檢視控制器的identifier為123
    SecondViewController *secondVc = [self.storyboard instantiateViewControllerWithIdentifier:@"123"];
    // 實現block
    secondVc.backValue = ^(NSString *tel)
    {
        self.lable.text = tel;
    };
    [self presentViewController:secondVc animated:YES completion:nil];
}

@property (weak, nonatomic) IBOutlet UILabel *lable;

// 宣告一個block(block的定義使用copy)
@property (copy , nonatomic) void(^backValue)(NSString *lableText);

- (IBAction)dissmissBackToViewController:(id)sender
{
    // 當返回的時候，在block中傳值
    self.backValue(self.lable.text);
    [self dismissViewControllerAnimated:YES completion:nil];
}