block實現介面傳值，block實現介面

block實現介面傳值，block實現介面

 在second的.h檔案裡面

首先定義一個 BLOCK傳回型別為空白，參數是你要傳的類型這裡是NSString

typedefvoid (^LJFBlock)(NSString *str);

然後聲明一個LJFBlock類型測屬性（用於下個介面的傳參）

@property (nonatomic,copy) LJFBlock block;

然後在second的.m檔案裡面

裡面要出發跳轉傳值的裡面把要傳的值self.secondTextField.text通過 self.ljfblock傳進來

- (IBAction)backBtnClick:(id)sender {

        self.ljfblock(self.secondTextField.text);

    [self.navigationControllerpopToRootViewControllerAnimated:YES];    

}

其次在First的.m裡面

- (IBAction)FirstBtnClick:(id)sender {    

    SecondViewController *second = [[SecondViewControlleralloc]initWithNibName:@"SecondViewController"bundle:nil];

    second.ljfblock  = ^(NSString *Str){

        self.firstTextField.text = Str;

    };

    [self.navigationControllerpushViewController:second animated:YES];

}

如所示