Swiftgram/AsyncDisplayKit/Layout/ASLayoutSpec+Subclasses.h
Michael Schneider 2f99951732 [Layout] Move [ASLayoutSpec children] from std::map to NSMutableArray (#2253)
* Initial commit to move [ASLayoutSpec children] from std::map to NSMutableArray

* Add NSFastEnumeration to ASLayoutable

* ASNullLayoutSpec is a Singleton now

* Move ASLayoutSpecPrivate in Private folder

* Move to NSArrayPointer and remove ASNullLayoutSpec

* Revert "Move to NSArrayPointer and remove ASNullLayoutSpec"

This reverts commit 9ab9cf7024b1f6e1984d84fe58af2b84e84cdf94.

* Move to childAtIndex: and setChild:atIndex:
2016-09-27 19:41:45 -04:00

65 lines
2.1 KiB
Objective-C

//
// ASLayoutSpec+Subclasses.h
// AsyncDisplayKit
//
// Created by Michael Schneider on 9/15/16.
// Copyright © 2016 Facebook. All rights reserved.
//
#import <AsyncDisplayKit/AsyncDisplayKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface ASLayoutSpec (Subclassing)
/**
* Helper method for finalLayoutable support
*
* @warning If you are getting recursion crashes here after implementing finalLayoutable, make sure
* that you are setting isFinalLayoutable flag to YES. This must be one BEFORE adding a child
* to the new ASLayoutable.
*
* For example:
* - (id<ASLayoutable>)finalLayoutable
* {
* ASInsetLayoutSpec *insetSpec = [[ASInsetLayoutSpec alloc] init];
* insetSpec.insets = UIEdgeInsetsMake(10,10,10,10);
* insetSpec.isFinalLayoutable = YES;
* [insetSpec setChild:self];
* return insetSpec;
* }
*
* @see finalLayoutable
*/
- (id<ASLayoutable>)layoutableToAddFromLayoutable:(id<ASLayoutable>)child;
/**
* Adds a child with the given identifier to this layout spec.
*
* @param child A child to be added.
*
* @param index An index associated with the child.
*
* @discussion Every ASLayoutSpec must act on at least one child. The ASLayoutSpec base class takes the
* responsibility of holding on to the spec children. Some layout specs, like ASInsetLayoutSpec,
* only require a single child.
*
* For layout specs that require a known number of children (ASBackgroundLayoutSpec, for example)
* a subclass can use the setChild method to set the "primary" child. It should then use this method
* to set any other required children. Ideally a subclass would hide this from the user, and use the
* setChild:forIndex: internally. For example, ASBackgroundLayoutSpec exposes a backgroundChild
* property that behind the scenes is calling setChild:forIndex:.
*/
- (void)setChild:(id<ASLayoutable>)child atIndex:(NSUInteger)index;
/**
* Returns the child added to this layout spec using the given index.
*
* @param index An identifier associated with the the child.
*/
- (nullable id<ASLayoutable>)childAtIndex:(NSUInteger)index;
@end
NS_ASSUME_NONNULL_END