block note

ios

use block as local var

void (^someBlock)(NSMutableArray *,id) = ^(NSMutableArray *items,NSString *item) {
       //do some thing
};

someBlock(items, item);

use block as type

1

@property (nonatomic, strong) returnType(^propertyName)(arguments);

e.g.
@property (nonatomic, strong) void(^onSelectedCustomer)(NSArray *customers);

2

typedef returnType(^name)(arguments);

e.g.
typedef void(^BlockType)(id);
@property (nonatomic, strong) BlockType block;

use block as method parameter

- (void)methodWithBlock:(returnType(^)(arguments))block

e.g.
- (void)loginAnimated:(BOOL)animated completion:(void(^)(void))completion failed:(void(^)(void))failed;