iOS block的写法

How Do I Declare A Block in Objective-C?

```

这是我的代码

```

As a local variable:

```objc

returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};

```

As a property:

```

@property (nonatomic, copy, nullability) returnType (^blockName)(parameterTypes);

```

As a method parameter:

```

- (void)someMethodThatTakesABlock:(returnType (^nullability)(parameterTypes))blockName;

```

As an argument to a method call:

```

[someObject someMethodThatTakesABlock:^returnType (parameters) {...}];

```

As a parameter to a C function:

void SomeFunctionThatTakesABlock(returnType (^blockName)(parameterTypes));

As a typedef:

typedef returnType (^TypeName)(parameterTypes);

TypeName blockName = ^returnType(parameters) {...};

转载来自  http://fuckingblocksyntax.com/