Constructing Block Objects
03 May 2014
- Example block object defined as function：
NSString* (^intToString)(NSUInteger) = ^(NSUInteger paramInteger){
NSString *result = [NSString stringWithFormat:@"%lu",
(unsigned long)paramInteger];
return result;
};
typedef the signature of block object:
typedef NSString* (^IntToStringConverter)(NSUInteger paramInteger);
- Define a Objective-C method that accepts both an integer and a block object of type:
- (NSString *) convertIntToString:(NSUInteger)paramInteger usingBlockObject:(IntToStringConverter)paramBlockObject{
return paramBlockObject(paramInteger); }
- Calling the block object in another method:
- (void) doTheConversion{
NSString *result = [self convertIntToString:123
usingBlockObject:intToString];
NSLog(@"result = %@", result);
}
- Example block object defined as a function:
- (void) doTheConversion{
IntToStringConverter inlineConverter = ^(NSUInteger paramInteger){
NSString *result = [NSString stringWithFormat:@"%lu",
(unsigned long)paramInteger];
return result; };
NSString *result = [self convertIntToString:123
usingBlockObject:inlineConverter];
NSLog(@"result = %@", result);
}
- Construct a block object while passing it as a parameter:
- (void) doTheConversion{
NSString *result =
[self convertIntToString:123
usingBlockObject:^NSString *(NSUInteger paramInteger) {
NSString *result = [NSString stringWithFormat:@"%lu",
(unsigned long)paramInteger];
return result;
}];
NSLog(@"result = %@", result);
}