如何创建我自己的方法，以块作为参数，我可以调用以后？ [英] How can I create my own methods which take a block as an argument and which I can call later?

问题描述

我已经尝试过以下的操作。

  #import< UIKit / UIKit.h> 
 typedef void（^ viewCreator）（void）; 
 
 @interface blocks2ViewController：UIViewController 
 {
} 
  - （void）createButtonUsingBlocks：（viewCreator *）block; 
 
 @end 
 
 
  - （void）viewDidLoad {
 [super viewDidLoad]; 
 [self createButtonUsingBlocks：^（NSString * name）{
 UIButton * dummyButton = [[UIButton alloc] initWithFrame：CGRectMake（50，50，200，100） 
 dummyButton.backgroundColor = [UIColor greenColor]; 
 [self.view addSubview：dummyButton]; 
}]; 
} 
 
  - （void）createButtonUsingBlocks：（viewCreator *）block 
 {
 // Do something 
 NSLog（@inside creator）; 
} 
  

我还试图将块变量传递给我的自定义方法，成功。

更新

p>

这是档案 is.h ：

  #import< UIKit / UIKit.h> 
 
 typedef void（^ viewCreator）（void）; 
 
 @interface blocks2ViewController：UIViewController 
 {
 
} 
  - （void）createButtonUsingBlocks：（viewCreator） 
 @end 
  

这是 .m 档案：

  #importblocks2ViewController.h
 
 @implementation blocks2ViewController 
 //实现viewDidLoad在加载视图之后执行额外的设置，通常来自nib。 
  - （void）viewDidLoad {
 [super viewDidLoad]; 
 [self createButtonUsingBlocks：^（NSString * name）{
 UIButton * dummyButton = [[UIButton alloc] initWithFrame：CGRectMake（50，50，200，100） 
 dummyButton.backgroundColor = [UIColor greenColor]; 
 [self.view addSubview：dummyButton]; 
 [dummyButton release]; 
}]; 
} 
 
  - （void）didReceiveMemoryWarning {
 //如果没有超级视图，则释放视图。 
 [super didReceiveMemoryWarning]; 
 
 //释放所有未使用的缓存数据，图像等。 
} 
 
  - （void）viewDidUnload {
 //释放主视图的任何保留的子视图。 
 //例如self.myOutlet = nil; 
} 
 
 // ... 
 
  - （void）createButtonUsingBlocks：（viewCreator）block 
 {
 // viewCreator; 
 NSLog（@inside creator）; 
} 
 @end 
  

解决方案

首先如果要让您的块接受字符串参数， typedef 是关闭的：

  typedef void（^ viewCreator）（NSString *）; 
  

其次的块类型是：

  ReturnType（^）（ParameterTypes ...）
  

b $ b

而不是

  ReturnType（^ *）（ParameterTypes ...）
  

因此，不需要向 viewCreator 类型添加指针：

   - （void）createButtonUsingBlocks：（viewCreator） 
  

第三您实际上必须调用该块

   - （void）createButtonUsingBlocks：（viewCreator *）block {
 block（@button name） ; 
 // ... 
  

第四 UIButton 过度保留 - 您应该发布或 autorelease it：

  UIButton * dummyButton = [[UIButton alloc] initWithFrame：...] 
 // ... 
 [self.view addSubview：dummyButton]; 
 [dummyButton release]; 
  

投掷：

  #import< UIKit / UIKit.h> 
 typedef void（^ viewCreator）（NSString *）; 
 
 @interface blocks2ViewController：UIViewController {} 
  - （void）createButtonUsingBlocks：（viewCreator）block; 
 @end 
 
 @implementation blocks2ViewController 
  - （void）viewDidLoad {
 [super viewDidLoad]; 
 [self createButtonUsingBlocks：^（NSString * name）{
 UIButton * dummyButton = 
 [[UIButton alloc] initWithFrame：CGRectMake（50，50，200，100） 
 dummyButton.backgroundColor = [UIColor greenColor]; 
 [self.view addSubview：dummyButton]; 
 [dummyButton release]; 
}]; 
} 
 
  - （void）createButtonUsingBlocks：（viewCreator）block {
 block（@my button name）; 
} 
 @end 
  

How can I create my own methods which take a block as an argument and which I can call later?

I have tried following things.

#import <UIKit/UIKit.h>
typedef void (^viewCreator)(void);

@interface blocks2ViewController : UIViewController
{
}
-(void)createButtonUsingBlocks:(viewCreator *)block;

@end


- (void)viewDidLoad {
  [super viewDidLoad];
  [self createButtonUsingBlocks:^(NSString * name) {
        UIButton *dummyButton = [[UIButton alloc]initWithFrame:CGRectMake(50, 50, 200, 100)];
        dummyButton.backgroundColor = [UIColor greenColor];
        [self.view addSubview:dummyButton];
  }];
}

-(void)createButtonUsingBlocks:(viewCreator *)block
{
    //    Do something
    NSLog(@"inside creator");
}

I have also tried to pass the block variable to my custom method but without any success. Why it is so and what is the right way to do this?

---

Update

This is file is.h:

 #import <UIKit/UIKit.h>

typedef void (^viewCreator)(void);

@interface blocks2ViewController : UIViewController
{

}
- (void)createButtonUsingBlocks:(viewCreator)block;
@end

And this is the .m file:

#import "blocks2ViewController.h"

@implementation blocks2ViewController
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
        [self createButtonUsingBlocks:^(NSString * name) {
        UIButton *dummyButton = [[UIButton alloc]initWithFrame:CGRectMake(50, 50, 200, 100)];
        dummyButton.backgroundColor = [UIColor greenColor];
        [self.view addSubview:dummyButton];
        [dummyButton release];
    }];
}

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

// ...

-(void)createButtonUsingBlocks:(viewCreator)block
{
//    viewCreator;
    NSLog(@"inside creator");
}
@end

解决方案

First the typedef is off if you want to let your blocks take a string parameter:

typedef void (^viewCreator)(NSString*);

Secondly the type for blocks is:

ReturnType (^)(ParameterTypes...)

and not

ReturnType (^*)(ParameterTypes...)

Thus there is no need to add pointers to the viewCreator type:

- (void)createButtonUsingBlocks:(viewCreator)block;

Third you actually have to call the block if you are not doing that yet:

-(void)createButtonUsingBlocks:(viewCreator *)block {
    block(@"button name");
    // ...

Fourth and last, the UIButton is over-retained - you should release or autorelease it:

UIButton *dummyButton = [[UIButton alloc] initWithFrame:...];
// ...    
[self.view addSubview:dummyButton];
[dummyButton release];

Throwing all that together:

#import <UIKit/UIKit.h>
typedef void (^viewCreator)(NSString*);

@interface blocks2ViewController : UIViewController {}
-(void)createButtonUsingBlocks:(viewCreator)block;      
@end

@implementation blocks2ViewController
- (void)viewDidLoad {
    [super viewDidLoad];  
    [self createButtonUsingBlocks:^(NSString *name) {
        UIButton *dummyButton = 
            [[UIButton alloc] initWithFrame:CGRectMake(50, 50, 200, 100)];
        dummyButton.backgroundColor = [UIColor greenColor];
        [self.view addSubview:dummyButton];
        [dummyButton release];
    }];
}

-(void)createButtonUsingBlocks:(viewCreator)block {
    block(@"my button name");
}
@end

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