test

How Do I Declare A Block in Objective-C?

As alocal variable:

```

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

```

As aproperty:

```

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

```

As amethod parameter:

```

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

```

As anargument to a method call:

```

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

```

As aparameter to a C function:

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

As atypedef:

typedef returnType (^TypeName)(parameterTypes);

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

转载来自http://fuckingblocksyntax.com/