mirror of
https://github.com/Instagram/IGListKit
synced 2026-05-14 21:08:48 +00:00
79348164a7
Summary: Started work on the plane to get this moving since #418 is up and ready to land. We'll likely need to spend some time fleshing out the API of this, and I think I'll split it up into a couple different PRs once ready for review. Putting this up now to get early feedback. This adds an auto-diffing section controller as outlined in #38. There are several key parts: - Subclass a new section controller `IGListAutoSectionController` (naming wip) - Connect a data source - Implement the data source methods that do 3 things: - Given a top-level object, transform it into an array of **diffable** view models - Given a view model, return a cell - Given a view model, return a size for a cell - A new protocol for the cell `IGListBindable` so that we can control when the cell is updated w/ the view model. - The most important part of this is that it unlocks moving and reloading a cell, which you can't do w/ `UICollectionView` - [ ] Unit test `reloadObjects:` - [x] Add Closes https://github.com/Instagram/IGListKit/pull/494 Reviewed By: amonshiz Differential Revision: D4696966 Pulled By: rnystrom fbshipit-source-id: f21b8341b3ed4389f2a4a106d0d316f481ba6943
78 lines
2.8 KiB
Objective-C
78 lines
2.8 KiB
Objective-C
/**
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* Copyright (c) 2016-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*/
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#import <Foundation/Foundation.h>
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#import <IGListKit/IGListMacros.h>
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#import <IGListKit/IGListSectionType.h>
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#import <IGListKit/IGListSectionController.h>
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#import <IGListKit/IGListBindingSectionControllerSelectionDelegate.h>
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#import <IGListKit/IGListBindingSectionControllerDataSource.h>
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@protocol IGListDiffable;
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@protocol IGListBindable;
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@class IGListBindingSectionController;
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NS_ASSUME_NONNULL_BEGIN
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/**
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This section controller uses a data source to transform its "top level" object into an array of diffable view models.
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It then automatically binds each view model to cells via the `IGListBindable` protocol.
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Models used with `IGListBindingSectionController` should take special care to always return `YES` for identical
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objects. That is, any objects with matching `-diffIdentifier`s should always be equal, that way the section controller
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can create new view models via the data source, create a diff, and update the specific cells that have changed.
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In Objective-C, your `-isEqualToDiffableObject:` can simply be:
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```
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- (BOOL)isEqualToDiffableObject:(id)object {
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return YES;
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}
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```
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In Swift:
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```
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func isEqual(toDiffableObject object: IGListDiffable?) -> Bool {
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return true
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}
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```
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Only when `-diffIdentifier`s match is object equality compared, so you can assume the class is the same, and the
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instance has already been checked.
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*/
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@interface IGListBindingSectionController : IGListSectionController<IGListSectionType>
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/**
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A data source that transforms a top-level object into view models, and returns cells and sizes for given view models.
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*/
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@property (nonatomic, weak, nullable) id<IGListBindingSectionControllerDataSource> dataSource;
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/**
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A delegate that receives selection events from cells in an `IGListBindingSectionController` instance.
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*/
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@property (nonatomic, weak, nullable) id<IGListBindingSectionControllerSelectionDelegate> selectionDelegate;
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/**
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The array of view models created from the data source. Values are changed when the top-level object changes or by
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calling `-updateAnimated:completion:` manually.
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*/
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@property (nonatomic, strong, readonly) NSArray<id<IGListDiffable>> *viewModels;
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/**
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Tells the section controller to query for new view models, diff the changes, and update its cells.
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@param animated A flag indicating if the transition should be animated or not.
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@param completion An optional completion block executed after updates finish. Parameter is YES if updates were applied.
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*/
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- (void)updateAnimated:(BOOL)animated completion:(nullable void (^)(BOOL updated))completion;
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@end
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NS_ASSUME_NONNULL_END
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