//  聲明 
  void(^blockName)(int num,NSString *string); 
//  實(shí)現(xiàn) 
  blockName = ^(int num,NSString *string) 
  { 
    NSLog(@"%d,%@",num,string); 
  }; 
//  調(diào)用 
  blockName(520,@"phyone_"); 
} 

- (void)viewDidLoad { 
  [super viewDidLoad]; 
  self.view.backgroundColor = [UIColor purpleColor]; 
 UILabel *lable = [[UILabel alloc]initWithFrame:CGRectMake(100, 200, 200, 100)]; 
  lable.backgroundColor = [UIColor brownColor]; 
  [self.view addSubview:lable]; 
   
  UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tap)]; 
  [self.view addGestureRecognizer:tap]; 
} 
- (void)tap 
{ 
  Next_ViewController *NVC = [[Next_ViewController alloc]init]; 
  NVC.block = ^(NSString *content){ 
    NSLog(@"%@",content); 
    UIButton *button = [[UIButton alloc]initWithFrame:CGRectMake(100, 200, 100, 100)]; 
    [button setTitle:content forState:UIControlStateNormal]; 
    button.backgroundColor = [UIColor orangeColor]; 
    [self.view addSubview:button]; 
  }; 
  [self presentViewController:NVC animated:YES completion:nil]; 
} 

//block 是分配在棧里面的用copy 
@property(nonatomic,copy) void(^block)(NSString *content); 

<p style="margin-top: 0px; margin-bottom: 0px; font-family: Menlo;"><span style="font-size:12px;">{</span></p>
<p style="margin-top: 0px; margin-bottom: 0px; font-family: Menlo;"><span style="font-size:12px;">  void(^imageNameBlock_1)(NSString *imageName);</span></p>
<p style="margin-top: 0px; margin-bottom: 0px; font-family: Menlo;"><span style="font-size:12px;">  void(^lableBlock)(NSString *tontentText);</span></p>
<p style="margin-top: 0px; margin-bottom: 0px; font-family: Menlo;"><span style="font-size:12px;">}</span></p> 

- (void)viewDidLoad { 
  [super viewDidLoad]; 
  self.view.backgroundColor = [UIColor orangeColor]; 
  UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom]; 
  button.frame = CGRectMake(100, 200, 100, 50); 
  [button setTitle:@"123456" forState:UIControlStateNormal]; 
  button.backgroundColor = [UIColor redColor]; 
  [button addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside]; 
  [self.view addSubview:button]; 
} 
- (void)buttonAction:(UIButton *)sender 
{ 
//  點(diǎn)擊按鈕 返回上一個(gè)頁(yè)面 同時(shí)通過(guò)block 把這個(gè)值傳到上一個(gè)頁(yè)面 
  self.block(sender.titleLabel.text); 
  [self dismissViewControllerAnimated:nil completion:nil]; 
}

 1.局部變量 
 定義一個(gè)圖片名字的Block 
 */ 
//  局部變量 
   
  void(^imageNameBlock)(NSString *imageName); 
//  如果想修改Block里面的值 需添加__block修飾 
   
//  __block UIImage *image; 
  imageNameBlock = ^(NSString *imageName) 
  { 
    image = [UIImage imageNamed:imageName]; 
    self.view.backgroundColor = [UIColor colorWithPatternImage:image]; 
  }; 
  imageNameBlock(@"17.jpg"); 

//  全局變量 
//  block循環(huán) 引用 解決 我們用弱引用 __block 
  __weak ViewController *VC = self; 
   
  __block UIImage *image = nil; 
  imageNameBlock_1 = ^(NSString *imageName) 
  { 
    image = [UIImage imageNamed:imageName]; 
    VC.view.backgroundColor = [UIColor colorWithPatternImage:image]; 
  }; 
  UILabel *lable = [[UILabel alloc]initWithFrame:CGRectMake(100, 200, 200, 100)]; 
  lable.backgroundColor = [UIColor brownColor]; 
  [self.view addSubview:lable]; 
   
  UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tap)]; 
  [self.view addGestureRecognizer:tap]; 

- (void)loadData 
{ 
  imageNameBlock_1(@"17.jpg"); 
} 
 
- (void)viewWillAppear:(BOOL)animated 
{ 
  [self loadData]; 
}