Swiftgram/AsyncDisplayKit/ASVisibilityProtocols.h
Hannah Troisi c857e809f4 Clean up header comments (for consistent Facebook licensing info) (#1741)
[Licensing] Clean up header comments (for consistent Facebook licensing info)
2016-06-11 23:31:39 -07:00

109 lines
3.4 KiB
Objective-C

//
// ASVisibilityProtocols.h
// AsyncDisplayKit
//
// Created by Garrett Moon on 4/27/16.
//
// 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 "ASLayoutRangeType.h"
#import "ASBaseDefines.h"
@class UIViewController;
ASDISPLAYNODE_EXTERN_C_BEGIN
extern ASLayoutRangeMode ASLayoutRangeModeForVisibilityDepth(NSUInteger visibilityDepth);
ASDISPLAYNODE_EXTERN_C_END
@protocol ASVisibilityDepth <NSObject>
/**
* @abstract Represents the number of user actions necessary to reach the view controller. An increased visibility
* depth indicates a higher number of user interactions for the view controller to be visible again. For example,
* an onscreen navigation controller's top view controller should have a visibility depth of 0. The view controller
* one from the top should have a visibility deptch of 1 as should the root view controller in the stack (because
* the user can hold the back button to pop to the root view controller).
*
* Visibility depth is used to automatically adjust ranges on range controllers (and thus free up memory) and can
* be used to reduce memory usage of other items as well.
*/
- (NSInteger)visibilityDepth;
- (void)visibilityDepthDidChange;
@end
/**
* @abstract Container view controllers should adopt this protocol to indicate that they will manage their child's
* visibilityDepth. For example, ASNavigationController adopts this protocol and manages its childrens visibility
* depth.
*
* If you adopt this protocol, you *must* also emit visibilityDepthDidChange messages to child view controllers.
*
* @param childViewController Expected to return the visibility depth of the child view controller.
*/
@protocol ASManagesChildVisibilityDepth <ASVisibilityDepth>
- (NSInteger)visibilityDepthOfChildViewController:(UIViewController *)childViewController;
@end
#define ASVisibilitySetVisibilityDepth \
- (void)setVisibilityDepth:(NSUInteger)visibilityDepth \
{ \
if (_visibilityDepth == visibilityDepth) { \
return; \
} \
_visibilityDepth = visibilityDepth; \
[self visibilityDepthDidChange]; \
}
#define ASVisibilityDepthImplementation \
- (NSInteger)visibilityDepth \
{ \
if (self.parentViewController && _parentManagesVisibilityDepth == NO) { \
_parentManagesVisibilityDepth = [self.parentViewController conformsToProtocol:@protocol(ASManagesChildVisibilityDepth)]; \
} \
\
if (_parentManagesVisibilityDepth) { \
return [(id <ASManagesChildVisibilityDepth>)self.parentViewController visibilityDepthOfChildViewController:self]; \
} \
return _visibilityDepth; \
}
#define ASVisibilityViewDidDisappearImplementation \
- (void)viewDidDisappear:(BOOL)animated \
{ \
[super viewDidDisappear:animated]; \
\
if (_parentManagesVisibilityDepth == NO) { \
[self setVisibilityDepth:1]; \
} \
}
#define ASVisibilityViewWillAppear \
- (void)viewWillAppear:(BOOL)animated \
{ \
[super viewWillAppear:animated]; \
\
if (_parentManagesVisibilityDepth == NO) { \
[self setVisibilityDepth:0]; \
} \
}
#define ASVisibilityDidMoveToParentViewController \
- (void)didMoveToParentViewController:(UIViewController *)parent \
{ \
[super didMoveToParentViewController:parent]; \
_parentManagesVisibilityDepth = NO; \
[self visibilityDepthDidChange]; \
}