108 lines
4.5 KiB
Objective-C

/*
* Copyright (c) 2014-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
*/
#import <AsyncDisplayKit/ASLayoutable.h>
#import <AsyncDisplayKit/ASAsciiArtBoxCreator.h>
/** A layout spec is an immutable object that describes a layout, loosely inspired by React. */
@interface ASLayoutSpec : NSObject <ASLayoutable>
/**
* Creation of a layout spec should only happen by a user in layoutSpecThatFits:. During that method, a
* layout spec can be created and mutated. Once it is passed back to ASDK, the isMutable flag will be
* set to NO and any further mutations will cause an assert.
*/
@property (nonatomic, assign) BOOL isMutable;
- (instancetype)init;
/**
* Adds a child to this layout spec using a default identifier.
*
* @param child A child to be added.
*
* @discussion Every ASLayoutSpec must act on at least one child. The ASLayoutSpec base class takes the
* reponsibility 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 should use this method to set the "primary" child. It can then use setChild:forIdentifier:
* to set any other required children. Ideally a subclass would hide this from the user, and use the
* setChild:forIdentifier: internally. For example, ASBackgroundLayoutSpec exposes a backgroundChild
* property that behind the scenes is calling setChild:forIdentifier:.
*/
- (void)setChild:(id<ASLayoutable>)child;
/**
* Adds a child with the given identifier to this layout spec.
*
* @param child A child to be added.
*
* @param identifier An identifier associated with the child.
*
* @discussion Every ASLayoutSpec must act on at least one child. The ASLayoutSpec base class takes the
* reponsibility 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 should use the setChild method to set the "primary" child. It can then use this method
* to set any other required children. Ideally a subclass would hide this from the user, and use the
* setChild:forIdentifier: internally. For example, ASBackgroundLayoutSpec exposes a backgroundChild
* property that behind the scenes is calling setChild:forIdentifier:.
*/
- (void)setChild:(id<ASLayoutable>)child forIdentifier:(NSString *)identifier;
/**
* Adds childen to this layout spec.
*
* @param children An array of ASLayoutable children to be added.
*
* @discussion Every ASLayoutSpec must act on at least one child. The ASLayoutSpec base class takes the
* reponsibility of holding on to the spec children. Some layout specs, like ASStackLayoutSpec,
* can take an unknown number of children. In this case, the this method should be used.
* For good measure, in these layout specs it probably makes sense to define
* setChild: and setChild:forIdentifier: methods to do something appropriate or to assert.
*/
- (void)setChildren:(NSArray *)children;
/**
* Get child methods
*
* There is a corresponding "getChild" method for the above "setChild" methods. If a subclass
* has extra layoutable children, it is recommended to make a corresponding get method for that
* child. For example, the ASBackgroundLayoutSpec responds to backgroundChild.
*
* If a get method is called on a spec that doesn't make sense, then the standard is to assert.
* For example, calling children on an ASInsetLayoutSpec will assert.
*/
/** Returns the child added to this layout spec using the default identifier. */
- (id<ASLayoutable>)child;
/**
* Returns the child added to this layout spec using the given identifier.
*
* @param identifier An identifier associated withe the child.
*/
- (id<ASLayoutable>)childForIdentifier:(NSString *)identifier;
/** Returns all children added to this layout spec. */
- (NSArray *)children;
@end
@interface ASLayoutSpec (Debugging) <ASLayoutableAsciiArtProtocol>
/**
* Used by other layout specs to create ascii art debug strings
*/
+ (NSString *)asciiArtStringForChildren:(NSArray *)children parentName:(NSString *)parentName direction:(ASStackLayoutDirection)direction;
+ (NSString *)asciiArtStringForChildren:(NSArray *)children parentName:(NSString *)parentName;
@end