components/NavigationDrawer/src/MDCBottomDrawerViewController.h - external/github.com/material-components/material-components-ios - Git at Google

 // Copyright 2018-present the Material Components for iOS authors. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 // http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #import <UIKit/UIKit.h>
 #import "MDCBottomDrawerPresentationController.h"
 #import "MDCBottomDrawerState.h"
 #import "MaterialElevation.h"
 #import "MaterialShadowElevations.h"

 @protocol MDCBottomDrawerHeader;
 @protocol MDCBottomDrawerViewControllerDelegate;

 /**
  View controller for containing a Material bottom drawer.
  */
 @interface MDCBottomDrawerViewController
     : UIViewController <MDCBottomDrawerPresentationControllerDelegate,
                         MDCElevatable,
                         MDCElevationOverriding>

 /**
  The main content displayed by the drawer.
  Its height is determined by the returned preferred content size.
  */
 @property(nonatomic, nullable) UIViewController *contentViewController;

 /**
  A header to display above the drawer's main content.
  Its height is determined by the returned preferred content size.
  */
 @property(nonatomic, nullable) UIViewController<MDCBottomDrawerHeader> *headerViewController;

 /**
  Setting the tracking scroll view allows the drawer scroll the content seamlessly as part of
  the drawer movement. This allows the provided scroll view to load the visible
  content as the drawer moves, and therefore not load all the content at once
  and allow to reuse the cells when using a UICollectionView or UITableView.
  */
 @property(nonatomic, weak, nullable) UIScrollView *trackingScrollView;

 /**
  The current state of the bottom drawer.
  */
 @property(nonatomic, readonly) MDCBottomDrawerState drawerState;

 /**
  The color applied to the background scrim.
  */
 @property(nonatomic, strong, nullable) UIColor *scrimColor;

 /**
  A Boolean value that determines whether the top handle of the drawer is hidden.
  Default is YES.
  */
 @property(nonatomic, assign, getter=isTopHandleHidden) BOOL topHandleHidden;

 /**
  The color applied to the top handle.
  Note: Make sure that topHandleHidden is set to NO to have the top handle be visible.
  Default is set to 0xE0E0E0.
  */
 @property(nonatomic, strong, nullable) UIColor *topHandleColor;

 /**
  The absolute height in points to which the drawer may expand initially.

  Defaults to 0, indicating no value has been set and it should use the default behavior of 50%
  of the screen's height.

  If the value is larger than the container's height, this will result the drawer being presented
  at fullscreen.

  Note: When TraitCollection is UIUserInterfaceSizeClassCompact or when using
  VoiceOver or SwitchControl, the drawer will always present at full screen.
  */
 @property(nonatomic, assign) CGFloat maximumInitialDrawerHeight;

 /**
  A flag allowing clients to opt-out of the drawer closing when the user taps outside the content.

  @default YES The drawer should dismiss on tap.
  */
 @property(nonatomic, assign) BOOL dismissOnBackgroundTap;

 /**
  A flag allowing clients to opt-in to handling background touch events.

  @default NO The drawer will not forward touch events.

  @discussion If set to YES and the delegate is an instance of @UIResponder, then the touch events
  that are not handled by the drawer content (aka touches on the background view) will be forwarded
  along to the delegate.

  Note: @dismissOnBackgroundTap should also be set to NO so that the events will propagate properly
  from the background tap through to the delegate. Setting @shouldForwardBackgroundTouchEvents to YES
  will also set @dismissOnBackgroundTap to NO.
  */
 @property(nonatomic, assign) BOOL shouldForwardBackgroundTouchEvents;

 /**
  A flag allowing clients to opt-in to the drawer adding additional height to the content to include
  the bottom safe area inset. This will remove the need for clients to calculate their content size
  with the bottom safe area when setting the preferredContentSize of the contentViewController.
  Defaults to NO.
  */
 @property(nonatomic, assign) BOOL shouldIncludeSafeAreaInContentHeight;

 /**
  A flag allowing clients to opt-in to adding additional height to the initial presentation of the
  drawer to include the bottom safe area inset. This will remove the need for clients to calculate
  their desired maximum height with the bottom safe area when setting the maximumInitialDrawerHeight.
  Defaults to NO.
  */
 @property(nonatomic, assign) BOOL shouldIncludeSafeAreaInInitialDrawerHeight;

 /**
  This flag allows clients to have the drawer content scroll below the status bar when no header is
  provided.

  Note: This flag is only applicable when @c headerViewController is nil. If @c headerViewController
  is non-nil, setting this flag to YES will have no effect.

  Defaults to NO.
 */
 @property(nonatomic, assign) BOOL shouldUseStickyStatusBar;

 /**
  The drawer's top shadow color. Defaults to black with 20% opacity.
  */
 @property(nonatomic, strong, nonnull) UIColor *drawerShadowColor;

 /**
  The drawer's elevation. Defaults to MDCShadowElevationNavDrawer.
  */
 @property(nonatomic, assign) MDCShadowElevation elevation;

 /**
  The bottom drawer delegate.
  */
 @property(nonatomic, weak, nullable) id<MDCBottomDrawerViewControllerDelegate> delegate;

 /**
  Determines if the header should always expand as it approaches the top of the screen.
  If the content height is smaller than the screen height then the header will not expand unless this
  flag is enabled.
  Defaults to NO.
  */
 @property(nonatomic, assign) BOOL shouldAlwaysExpandHeader;

 /**
  Determines the behavior of the drawer when the content size changes.
  If enabled, the drawer will automatically adjust the visible height as needed, otherwise the
  visible height will not be changed to reflect the updated content height.
  Defaults to NO.
  */
 @property(nonatomic, assign) BOOL shouldAdjustOnContentSizeChange;

 /**
  Sets the top corners radius for an MDCBottomDrawerState drawerState

  @param radius The corner radius to set the top corners.
  @param drawerState MDCBottomDrawerState the drawer state.
  */
 - (void)setTopCornersRadius:(CGFloat)radius forDrawerState:(MDCBottomDrawerState)drawerState;

 /**
  Returns the top corners radius for an MDCBottomDrawerState drawerState.

  If no radius has been set for a state, the value 0 is returned.

  @param drawerState MDCBottomDrawerState the drawer state.
  @return The corner radius to set the top corners.
  */
 - (CGFloat)topCornersRadiusForDrawerState:(MDCBottomDrawerState)drawerState;

 /**
  Sets the content offset Y of the drawer's content. If contentOffsetY is set to 0, the
  drawer will scroll to the start of its content.

  @param contentOffsetY the content offset Y of the scroll view.
  @param animated a bool if to animate the scrolling.
  */
 - (void)setContentOffsetY:(CGFloat)contentOffsetY animated:(BOOL)animated;

 /**
  Expands the drawer to fullscreen with animation.

  note: If the drawer has less content than the full screen,
  this method will still expand the drawer to fullscreen.

  @param duration The total duration of the animations, measured in seconds. If you specify a
  negative value or 0, the changes are made without animating them.

  @param completion A block object to be executed when the animation sequence ends. This block has
  no return value and takes a single Boolean argument that indicates whether or not the animations
  actually finished before the completion handler was called. If the duration of the animation is 0,
  this block is performed at the beginning of the next run loop cycle. This parameter may be NULL.
  */
 - (void)expandToFullscreenWithDuration:(CGFloat)duration
                             completion:(void (^__nullable)(BOOL finished))completion;

 /**
  A block that is invoked when the @c MDCBottomDrawerViewController receives a call to @c
  traitCollectionDidChange:. The block is called after the call to the superclass.
  */
 @property(nonatomic, copy, nullable) void (^traitCollectionDidChangeBlock)
     (MDCBottomDrawerViewController *_Nonnull bottomDrawer,
      UITraitCollection *_Nullable previousTraitCollection);

 @end

 /**
  Delegate for MDCBottomDrawerViewController.
  */
 @protocol MDCBottomDrawerViewControllerDelegate <NSObject>

 @optional
 /**
  Called when the top inset of the drawer changes due to size changes when moving into full screen
  to cover the status bar and safe area inset. Also if there is a top handle, the top inset will
  take into regards the handle height. The top inset indicates where the content can be safely
  laid out without it being clipped.

  @param controller The MDCBottomDrawerViewController.
  @param topInset The top inset in which the content should take into regards when being laid out.
  */
 - (void)bottomDrawerControllerDidChangeTopInset:(nonnull MDCBottomDrawerViewController *)controller
                                        topInset:(CGFloat)topInset;

 /**
  Called when the y-offset of the visible contents of the drawer (excluding shadow & scrim) have
  changed. This is triggered when the drawer is presented and dismissed as well as when the content
  is being dragged interactively.

  @param controller The MDCBottomDrawerViewController.
  @param yOffset The y-Offset of the top of the visible contents of the drawer.
  */
 - (void)bottomDrawerControllerDidChangeTopYOffset:
             (nonnull MDCBottomDrawerViewController *)controller
                                           yOffset:(CGFloat)yOffset;

 /**
  Called when the bottom drawer will begin animating to an open state. This is triggered when the VC
  is being presented. Add animations and/or completion to the transitionCoordinator to cause them to
  animate/complete alongside the drawer animation.

  @param controller The MDCBottomDrawerViewController.
  @param transitionCoordinator The transitionCoordinator handling the presentation transition.
  @param targetYOffset The target yOffset of the content after the animation completes.
  */
 - (void)bottomDrawerControllerWillTransitionOpen:(nonnull MDCBottomDrawerViewController *)controller
                                  withCoordinator:
                                      (nullable id<UIViewControllerTransitionCoordinator>)
                                          transitionCoordinator
                                    targetYOffset:(CGFloat)targetYOffset;

 /**
  Called when the bottom drawer has completed animating to the open state.

  @param controller The MDCBottomDrawerViewController.
  */
 - (void)bottomDrawerControllerDidEndOpenTransition:
     (nonnull MDCBottomDrawerViewController *)controller;

 /**
  Called when the bottom drawer will begin animating to a closed state. This is triggered when the VC
  is being dismissed. Add animations and/or completion to the transitionCoordinator to cause them to
  animate/complete alongside the drawer animation.

  @param controller The MDCBottomDrawerViewController.
  @param transitionCoordinator The transitionCoordinator handling the presentation transition.
  @param targetYOffset The target yOffset of the content after the animation completes.
  */
 - (void)
     bottomDrawerControllerWillTransitionClosed:(nonnull MDCBottomDrawerViewController *)controller
                                withCoordinator:(nullable id<UIViewControllerTransitionCoordinator>)
                                                    transitionCoordinator
                                  targetYOffset:(CGFloat)targetYOffset;

 /**
  Called when the bottom drawer has completed animating to the closed state.

  @param controller The MDCBottomDrawerViewController.
  */
 - (void)bottomDrawerControllerDidEndCloseTransition:
     (nonnull MDCBottomDrawerViewController *)controller;

 @end
	// Copyright 2018-present the Material Components for iOS authors. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#import <UIKit/UIKit.h>
	#import "MDCBottomDrawerPresentationController.h"
	#import "MDCBottomDrawerState.h"
	#import "MaterialElevation.h"
	#import "MaterialShadowElevations.h"

	@protocol MDCBottomDrawerHeader;
	@protocol MDCBottomDrawerViewControllerDelegate;

	/**
	View controller for containing a Material bottom drawer.
	*/
	@interface MDCBottomDrawerViewController
	: UIViewController <MDCBottomDrawerPresentationControllerDelegate,
	MDCElevatable,
	MDCElevationOverriding>

	/**
	The main content displayed by the drawer.
	Its height is determined by the returned preferred content size.
	*/
	@property(nonatomic, nullable) UIViewController *contentViewController;

	/**
	A header to display above the drawer's main content.
	Its height is determined by the returned preferred content size.
	*/
	@property(nonatomic, nullable) UIViewController<MDCBottomDrawerHeader> *headerViewController;

	/**
	Setting the tracking scroll view allows the drawer scroll the content seamlessly as part of
	the drawer movement. This allows the provided scroll view to load the visible
	content as the drawer moves, and therefore not load all the content at once
	and allow to reuse the cells when using a UICollectionView or UITableView.
	*/
	@property(nonatomic, weak, nullable) UIScrollView *trackingScrollView;

	/**
	The current state of the bottom drawer.
	*/
	@property(nonatomic, readonly) MDCBottomDrawerState drawerState;

	/**
	The color applied to the background scrim.
	*/
	@property(nonatomic, strong, nullable) UIColor *scrimColor;

	/**
	A Boolean value that determines whether the top handle of the drawer is hidden.
	Default is YES.
	*/
	@property(nonatomic, assign, getter=isTopHandleHidden) BOOL topHandleHidden;

	/**
	The color applied to the top handle.
	Note: Make sure that topHandleHidden is set to NO to have the top handle be visible.
	Default is set to 0xE0E0E0.
	*/
	@property(nonatomic, strong, nullable) UIColor *topHandleColor;

	/**
	The absolute height in points to which the drawer may expand initially.

	Defaults to 0, indicating no value has been set and it should use the default behavior of 50%
	of the screen's height.

	If the value is larger than the container's height, this will result the drawer being presented
	at fullscreen.

	Note: When TraitCollection is UIUserInterfaceSizeClassCompact or when using
	VoiceOver or SwitchControl, the drawer will always present at full screen.
	*/
	@property(nonatomic, assign) CGFloat maximumInitialDrawerHeight;

	/**
	A flag allowing clients to opt-out of the drawer closing when the user taps outside the content.

	@default YES The drawer should dismiss on tap.
	*/
	@property(nonatomic, assign) BOOL dismissOnBackgroundTap;

	/**
	A flag allowing clients to opt-in to handling background touch events.

	@default NO The drawer will not forward touch events.

	@discussion If set to YES and the delegate is an instance of @UIResponder, then the touch events
	that are not handled by the drawer content (aka touches on the background view) will be forwarded
	along to the delegate.

	Note: @dismissOnBackgroundTap should also be set to NO so that the events will propagate properly
	from the background tap through to the delegate. Setting @shouldForwardBackgroundTouchEvents to YES
	will also set @dismissOnBackgroundTap to NO.
	*/
	@property(nonatomic, assign) BOOL shouldForwardBackgroundTouchEvents;

	/**
	A flag allowing clients to opt-in to the drawer adding additional height to the content to include
	the bottom safe area inset. This will remove the need for clients to calculate their content size
	with the bottom safe area when setting the preferredContentSize of the contentViewController.
	Defaults to NO.
	*/
	@property(nonatomic, assign) BOOL shouldIncludeSafeAreaInContentHeight;

	/**
	A flag allowing clients to opt-in to adding additional height to the initial presentation of the
	drawer to include the bottom safe area inset. This will remove the need for clients to calculate
	their desired maximum height with the bottom safe area when setting the maximumInitialDrawerHeight.
	Defaults to NO.
	*/
	@property(nonatomic, assign) BOOL shouldIncludeSafeAreaInInitialDrawerHeight;

	/**
	This flag allows clients to have the drawer content scroll below the status bar when no header is
	provided.

	Note: This flag is only applicable when @c headerViewController is nil. If @c headerViewController
	is non-nil, setting this flag to YES will have no effect.

	Defaults to NO.
	*/
	@property(nonatomic, assign) BOOL shouldUseStickyStatusBar;

	/**
	The drawer's top shadow color. Defaults to black with 20% opacity.
	*/
	@property(nonatomic, strong, nonnull) UIColor *drawerShadowColor;

	/**
	The drawer's elevation. Defaults to MDCShadowElevationNavDrawer.
	*/
	@property(nonatomic, assign) MDCShadowElevation elevation;

	/**
	The bottom drawer delegate.
	*/
	@property(nonatomic, weak, nullable) id<MDCBottomDrawerViewControllerDelegate> delegate;

	/**
	Determines if the header should always expand as it approaches the top of the screen.
	If the content height is smaller than the screen height then the header will not expand unless this
	flag is enabled.
	Defaults to NO.
	*/
	@property(nonatomic, assign) BOOL shouldAlwaysExpandHeader;

	/**
	Determines the behavior of the drawer when the content size changes.
	If enabled, the drawer will automatically adjust the visible height as needed, otherwise the
	visible height will not be changed to reflect the updated content height.
	Defaults to NO.
	*/
	@property(nonatomic, assign) BOOL shouldAdjustOnContentSizeChange;

	/**
	Sets the top corners radius for an MDCBottomDrawerState drawerState

	@param radius The corner radius to set the top corners.
	@param drawerState MDCBottomDrawerState the drawer state.
	*/
	- (void)setTopCornersRadius:(CGFloat)radius forDrawerState:(MDCBottomDrawerState)drawerState;

	/**
	Returns the top corners radius for an MDCBottomDrawerState drawerState.

	If no radius has been set for a state, the value 0 is returned.

	@param drawerState MDCBottomDrawerState the drawer state.
	@return The corner radius to set the top corners.
	*/
	- (CGFloat)topCornersRadiusForDrawerState:(MDCBottomDrawerState)drawerState;

	/**
	Sets the content offset Y of the drawer's content. If contentOffsetY is set to 0, the
	drawer will scroll to the start of its content.

	@param contentOffsetY the content offset Y of the scroll view.
	@param animated a bool if to animate the scrolling.
	*/
	- (void)setContentOffsetY:(CGFloat)contentOffsetY animated:(BOOL)animated;

	/**
	Expands the drawer to fullscreen with animation.

	note: If the drawer has less content than the full screen,
	this method will still expand the drawer to fullscreen.

	@param duration The total duration of the animations, measured in seconds. If you specify a
	negative value or 0, the changes are made without animating them.

	@param completion A block object to be executed when the animation sequence ends. This block has
	no return value and takes a single Boolean argument that indicates whether or not the animations
	actually finished before the completion handler was called. If the duration of the animation is 0,
	this block is performed at the beginning of the next run loop cycle. This parameter may be NULL.
	*/
	- (void)expandToFullscreenWithDuration:(CGFloat)duration
	completion:(void (^__nullable)(BOOL finished))completion;

	/**
	A block that is invoked when the @c MDCBottomDrawerViewController receives a call to @c
	traitCollectionDidChange:. The block is called after the call to the superclass.
	*/
	@property(nonatomic, copy, nullable) void (^traitCollectionDidChangeBlock)
	(MDCBottomDrawerViewController *_Nonnull bottomDrawer,
	UITraitCollection *_Nullable previousTraitCollection);

	@end

	/**
	Delegate for MDCBottomDrawerViewController.
	*/
	@protocol MDCBottomDrawerViewControllerDelegate <NSObject>

	@optional
	/**
	Called when the top inset of the drawer changes due to size changes when moving into full screen
	to cover the status bar and safe area inset. Also if there is a top handle, the top inset will
	take into regards the handle height. The top inset indicates where the content can be safely
	laid out without it being clipped.

	@param controller The MDCBottomDrawerViewController.
	@param topInset The top inset in which the content should take into regards when being laid out.
	*/
	- (void)bottomDrawerControllerDidChangeTopInset:(nonnull MDCBottomDrawerViewController *)controller
	topInset:(CGFloat)topInset;

	/**
	Called when the y-offset of the visible contents of the drawer (excluding shadow & scrim) have
	changed. This is triggered when the drawer is presented and dismissed as well as when the content
	is being dragged interactively.

	@param controller The MDCBottomDrawerViewController.
	@param yOffset The y-Offset of the top of the visible contents of the drawer.
	*/
	- (void)bottomDrawerControllerDidChangeTopYOffset:
	(nonnull MDCBottomDrawerViewController *)controller
	yOffset:(CGFloat)yOffset;

	/**
	Called when the bottom drawer will begin animating to an open state. This is triggered when the VC
	is being presented. Add animations and/or completion to the transitionCoordinator to cause them to
	animate/complete alongside the drawer animation.

	@param controller The MDCBottomDrawerViewController.
	@param transitionCoordinator The transitionCoordinator handling the presentation transition.
	@param targetYOffset The target yOffset of the content after the animation completes.
	*/
	- (void)bottomDrawerControllerWillTransitionOpen:(nonnull MDCBottomDrawerViewController *)controller
	withCoordinator:
	(nullable id<UIViewControllerTransitionCoordinator>)
	transitionCoordinator
	targetYOffset:(CGFloat)targetYOffset;

	/**
	Called when the bottom drawer has completed animating to the open state.

	@param controller The MDCBottomDrawerViewController.
	*/
	- (void)bottomDrawerControllerDidEndOpenTransition:
	(nonnull MDCBottomDrawerViewController *)controller;

	/**
	Called when the bottom drawer will begin animating to a closed state. This is triggered when the VC
	is being dismissed. Add animations and/or completion to the transitionCoordinator to cause them to
	animate/complete alongside the drawer animation.

	@param controller The MDCBottomDrawerViewController.
	@param transitionCoordinator The transitionCoordinator handling the presentation transition.
	@param targetYOffset The target yOffset of the content after the animation completes.
	*/
	- (void)
	bottomDrawerControllerWillTransitionClosed:(nonnull MDCBottomDrawerViewController *)controller
	withCoordinator:(nullable id<UIViewControllerTransitionCoordinator>)
	transitionCoordinator
	targetYOffset:(CGFloat)targetYOffset;

	/**
	Called when the bottom drawer has completed animating to the closed state.

	@param controller The MDCBottomDrawerViewController.
	*/
	- (void)bottomDrawerControllerDidEndCloseTransition:
	(nonnull MDCBottomDrawerViewController *)controller;

	@end