Assign a variable inside a Block to a variable outside a Block

Question

I m getting an error      Variable is not assignable  missing   block type specifier    on the line aPerson   participant   How can I make sure the block can access the aPerson variable and the aPerson variable can be returned   Person  aPerson   nil    participants enumerateObjectsUsingBlock   id obj  NSUInteger idx  BOOL  stop           Person  participant    Person  obj       if   participant gender isEqualToString   M              aPerson   participant           stop   YES             return aPerson

User · Answer

Try   weak if you get any warning regarding retain cycle else use   block  Person  strongPerson    Person new     weak Person  weakPerson   person    Now you can refer weakPerson object inside block

User · Answer

When I saw the same error  I tried to resolve it like        block CGFloat docHeight   0 0         self evaluateJavaScript   document height  completionHandler   id height  NSError  error              height         NSLog             gt document height      height           docHeight    height floatValue             and its working fine  Just add     block   before Variable

User · Answer

You need to use this line of code to resolve your problem     block Person  aPerson   nil    For more details  please refer to this tutorial  Blocks and Variables

User · Answer

Just a reminder of a mistake I made myself too  the     block   declaration must be done when first declaring the variable  that is  OUTSIDE of the block  not inside of it  This should resolve problems mentioned in the comments about the variable not retaining its value outside of the block

User · Answer

yes block are the most used functionality   so in order to avoid the retain cycle we should avoid using the strong variable including self  inside the block  inspite use the  weak or weakself

User · Answer

To assign  a variable inside block which outside of block always use   block specifier before that variable your code should be like this -    block Person  aPerson   nil

User · Answer

Just use the   block prefix to declare and assign any type of variable inside a block   For example     block Person  aPerson   nil     block NSString  name   nil

User · Answer

block Person  aPerson   nil

[objective-c] Assign a variable inside a Block to a variable outside a Block

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