iOS Block介面反向傳值小demo

標籤：ted   UI   let   self   div   nss   btn   nonatomic   atom   

1、在第二個視圖控制器的.h檔案中定義聲明Block屬性：

// 定義block@property (nonatomic, copy) void (^NextViewControllerBlock)(NSString *tfText);@interface NextViewController () @property (weak, nonatomic) IBOutlet UITextField *inputTF; @end - (IBAction)BtnAction:(id)sender {       // 判斷block是否為空白    if (self.NextViewControllerBlock) {         self.NextViewControllerBlock(self.inputTF.text);}       [self.navigationController popViewControllerAnimated:YES];} 2、在第一個視圖中獲得第二個視圖控制器，並且用第二個視圖控制器來調用定義的屬性：@interface AViewController () @property (weak, nonatomic) IBOutlet UILabel *nextVCInfoLabel; @end  - (IBAction)btnClicked:(id)sender {       NextViewController*nextVC = [[NextViewController alloc]init]; nextVC.NextViewControllerBlock= ^(NSString *tfText) {      self.nextVCInfoLabel.text = tfText;  };       [self.navigationController pushViewController:nextVC animated:YES];  }

iOS Block介面反向傳值小demo