components/ButtonBar/src/private/MDCAppBarButtonBarBuilder.m - external/github.com/material-components/material-components-ios - Git at Google

 // Copyright 2016-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 "MDCAppBarButtonBarBuilder.h"

 #import <objc/runtime.h>
 #import "MaterialInk.h"

 #import "MaterialAvailability.h"
 #import "MDCButtonBar.h"
 #import "MDCButtonBarButton.h"
 #import "MDCButtonBar+Private.h"
 #import "MaterialButtons.h"

 // Additional insets for the left-most or right-most items.
 static const CGFloat kEdgeButtonAdditionalMargin = 4;

 // The default MDCButton's alpha for display state is 0.1 which in the context of bar buttons makes
 // it practically invisible. Setting button to a higher opacity is closer to what the button should
 // look like when it is disabled.
 static const CGFloat kDisabledButtonAlpha = (CGFloat)0.38;

 // Default content inset for buttons.
 static const UIEdgeInsets kButtonInset = {0, 12, 0, 12};

 // Indiana Jones style placeholder view for UINavigationBar. Ownership of UIBarButtonItem.customView
 // and UINavigationItem.titleView are normally transferred to UINavigationController but we plan to
 // steal them away. In order to avoid crashing during KVO updates, we steal the view away and
 // replace it with a sandbag view.
 @interface MDCButtonBarSandbagView : UIView
 @end

 @interface UIBarButtonItem (MDCHeaderInternal)

 // Internal version of the standard -customView property. When an item is pushed onto a
 // UINavigationController stack, any -customView object is moved over to this property. This
 // prevents UINavigationController from adding the customView to its own view hierarchy.
 @property(nonatomic, strong, setter=mdc_setCustomView:) UIView *mdc_customView;

 @end

 @implementation MDCAppBarButtonBarBuilder {
   NSMutableDictionary<NSNumber *, UIFont *> *_fonts;
   NSMutableDictionary<NSNumber *, UIColor *> *_titleColors;
 }

 - (instancetype)init {
   self = [super init];
   if (self) {
     _fonts = [NSMutableDictionary dictionary];
     _titleColors = [NSMutableDictionary dictionary];
   }
   return self;
 }

 - (nullable UIFont *)titleFontForState:(UIControlState)state {
   UIFont *font = _fonts[@(state)];
   if (!font && state != UIControlStateNormal) {
     font = _fonts[@(UIControlStateNormal)];
   }
   return font;
 }

 - (void)setTitleFont:(UIFont *)font forState:(UIControlState)state {
   _fonts[@(state)] = font;
 }

 - (UIColor *)titleColorForState:(UIControlState)state {
   UIColor *color = _titleColors[@(state)];
   if (!color && state != UIControlStateNormal) {
     color = _titleColors[@(UIControlStateNormal)];
   }
   return color;
 }

 - (void)setTitleColor:(UIColor *)color forState:(UIControlState)state {
   _titleColors[@(state)] = color;
 }

 - (void)updateTitleColorForButton:(UIButton *)button withItem:(UIBarButtonItem *)item {
   // Apply title colors to the button in order of descending priority (last one wins).

   // General buttonTitleColor (proxy for contextual tint color)
   [button setTitleColor:self.buttonTitleColor forState:UIControlStateNormal];

   // Explicit -setTitleColor:forState:
   for (NSNumber *state in _titleColors) {
     UIColor *color = _titleColors[state];
     [button setTitleColor:color forState:(UIControlState)state.intValue];
   }

   // The item's explicit tintColor
   if (item.tintColor) {
     [button setTitleColor:item.tintColor forState:UIControlStateNormal];
   }
 }

 #pragma mark - MDCBarButtonItemBuilding

 - (UIView *)buttonBar:(MDCButtonBar *)buttonBar
           viewForItem:(UIBarButtonItem *)buttonItem
           layoutHints:(MDCBarButtonItemLayoutHints)layoutHints {
   if (buttonItem == nil) {
     return nil;
   }

   // Transfer custom view ownership if necessary.
   [self transferCustomViewOwnershipForBarButtonItem:buttonItem];

   // Take the real custom view if it exists instead of sandbag view.
   UIView *customView =
       buttonItem.mdc_customView ? buttonItem.mdc_customView : buttonItem.customView;
   if (customView) {
     return customView;
   }

 // NOTE: This assertion does not occur in release builds because it is accessing a private api.
 #if DEBUG
   NSAssert(![[buttonItem valueForKey:@"isSystemItem"] boolValue],
            @"Instances of %@ must not be initialized with %@ when working with %@."
            @" This is because we cannot extract the system item type from the item.",
            NSStringFromClass([buttonItem class]),
            NSStringFromSelector(@selector(initWithBarButtonSystemItem:target:action:)),
            NSStringFromClass([MDCButtonBar class]));
 #endif

 #ifdef __IPHONE_14_0
   MDCButtonBarButton *button;
   if (@available(iOS 14.0, *)) {
     button = [MDCButtonBarButton buttonWithType:UIButtonTypeCustom
                                   primaryAction:buttonItem.primaryAction];
   } else {
     button = [[MDCButtonBarButton alloc] init];
   }
 #else
   MDCButtonBarButton *button = [[MDCButtonBarButton alloc] init];
 #endif
   [button setBackgroundColor:[UIColor clearColor] forState:UIControlStateNormal];
   button.disabledAlpha = kDisabledButtonAlpha;
   button.enableRippleBehavior = buttonBar.enableRippleBehavior;
   if (buttonBar.inkColor) {
     button.inkColor = buttonBar.inkColor;
   }

   button.exclusiveTouch = YES;

   [MDCAppBarButtonBarBuilder configureButton:button fromButtonItem:buttonItem];

   button.uppercaseTitle = buttonBar.uppercasesButtonTitles;
   [button setUnderlyingColorHint:self.buttonUnderlyingColor];
   for (NSNumber *state in _fonts) {
     UIFont *font = _fonts[state];
     [button setTitleFont:font forState:(UIControlState)state.intValue];
   }
   [self updateTitleColorForButton:button withItem:buttonItem];

 #if MDC_AVAILABLE_SDK_IOS(13_0)
   if (@available(iOS 13.0, *)) {
     button.largeContentImage = self.largeContentImage;
     button.largeContentTitle = self.largeContentTitle;
   }
 #endif

   [self updateButton:button withItem:buttonItem barMetrics:UIBarMetricsDefault];

 #ifdef __IPHONE_13_4
   if (@available(iOS 13.4, *)) {
     // Because some iOS 13 betas did not have the UIPointerInteraction class, we need to verify
     // that it exists before attempting to use it.
     if (NSClassFromString(@"UIPointerInteraction")) {
       UIPointerInteraction *pointerInteraction =
           [[UIPointerInteraction alloc] initWithDelegate:buttonBar];
       [button addInteraction:pointerInteraction];
     }
   }
 #endif

   // Contrary to intuition, UIKit provides the UIBarButtonItem as the action's first argument when
   // bar buttons are tapped, NOT the button itself. Simply adding the item's target/action to the
   // button does not allow us to pass the expected argument to the target.
   //
   // MDCButtonBar provides didTapButton:event: to which we can pass button events
   // so that the correct argument is ultimately passed along.
   [button addTarget:buttonBar
                 action:@selector(didTapButton:event:)
       forControlEvents:UIControlEventTouchUpInside];
 #if MDC_AVAILABLE_SDK_IOS(14_0)
   if (@available(iOS 14.0, *)) {
     if (buttonItem.menu) {
       // Setting the menu as primary action will result in the target / action pair not being
       // called. Setting the primaryAction on a menu item will result in it not having a target /
       // action pair anymore and not taking a new one on until primaryAction is cleared again.
       button.menu = buttonItem.menu;
       if (!buttonItem.primaryAction) {
         button.showsMenuAsPrimaryAction = YES;
       }
     }
   }
 #endif

   UIEdgeInsets contentInsets = [MDCAppBarButtonBarBuilder
       contentInsetsForButton:button
               layoutPosition:buttonBar.layoutPosition
                  layoutHints:layoutHints
              layoutDirection:[buttonBar effectiveUserInterfaceLayoutDirection]
           userInterfaceIdiom:[self usePadInsetsForButtonBar:buttonBar] ? UIUserInterfaceIdiomPad
                                                                        : UIUserInterfaceIdiomPhone];

   button.contentEdgeInsets = contentInsets;
   button.enabled = buttonItem.enabled;
   button.accessibilityLabel = buttonItem.accessibilityLabel;
   button.accessibilityHint = buttonItem.accessibilityHint;
   button.accessibilityValue = buttonItem.accessibilityValue;
   button.accessibilityIdentifier = buttonItem.accessibilityIdentifier;

   return button;
 }

 #pragma mark - Private

 // Used to determine whether or not to apply insets relevant for iPad or use smaller iPhone size
 // Because only widths are affected, we use horizontal size class
 - (BOOL)usePadInsetsForButtonBar:(MDCButtonBar *)buttonBar {
   const BOOL isPad = [[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad;
   if (isPad && buttonBar.traitCollection.horizontalSizeClass == UIUserInterfaceSizeClassRegular) {
     return YES;
   }
   return NO;
 }

 + (UIEdgeInsets)contentInsetsForButton:(MDCButton *)button
                         layoutPosition:(MDCButtonBarLayoutPosition)layoutPosition
                            layoutHints:(MDCBarButtonItemLayoutHints)layoutHints
                        layoutDirection:(UIUserInterfaceLayoutDirection)layoutDirection
                     userInterfaceIdiom:(UIUserInterfaceIdiom)userInterfaceIdiom {
   UIEdgeInsets contentInsets = kButtonInset;
   if ([button currentImage] || [button currentTitle].length) {
     CGFloat additionalInset = kEdgeButtonAdditionalMargin;
     BOOL isFirstButton = (layoutHints & MDCBarButtonItemLayoutHintsIsFirstButton) ==
                          MDCBarButtonItemLayoutHintsIsFirstButton;
     BOOL isLastButton = (layoutHints & MDCBarButtonItemLayoutHintsIsLastButton) ==
                         MDCBarButtonItemLayoutHintsIsLastButton;
     if (isFirstButton && layoutPosition == MDCButtonBarLayoutPositionLeading) {
       // Left-most button in LTR, and right-most button in RTL.
       if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
         contentInsets.left += additionalInset;
       } else {
         contentInsets.right += additionalInset;
       }
     } else if (isFirstButton && layoutPosition == MDCButtonBarLayoutPositionTrailing) {
       // Right-most button in LTR, and left-most button in RTL.
       if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
         contentInsets.right += additionalInset;
       } else {
         contentInsets.left += additionalInset;
       }
     }
     if (isLastButton && layoutPosition == MDCButtonBarLayoutPositionTrailing) {
       // Left-most button in LTR, and right-most button in RTL.
       if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
         contentInsets.left += additionalInset;
       } else {
         contentInsets.right += additionalInset;
       }
     } else if (isLastButton && layoutPosition == MDCButtonBarLayoutPositionLeading) {
       // Right-most button in LTR, and left-most button in RTL.
       if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
         contentInsets.right += additionalInset;
       } else {
         contentInsets.left += additionalInset;
       }
     }
   } else {
     NSAssert(0, @"No button title or image");
   }

   return contentInsets;
 }

 + (void)configureButton:(MDCButton *)destinationButton
          fromButtonItem:(UIBarButtonItem *)sourceButtonItem {
   if (sourceButtonItem == nil || destinationButton == nil) {
     return;
   }

   if (sourceButtonItem.title != nil) {
     [destinationButton setTitle:sourceButtonItem.title forState:UIControlStateNormal];
   }
   if (sourceButtonItem.image != nil) {
     [destinationButton setImage:sourceButtonItem.image forState:UIControlStateNormal];
   }
   if (sourceButtonItem.tintColor != nil) {
     destinationButton.tintColor = sourceButtonItem.tintColor;
   }

   if (sourceButtonItem.title) {
     destinationButton.inkStyle = MDCInkStyleBounded;
   } else {
     destinationButton.inkStyle = MDCInkStyleUnbounded;
   }

   destinationButton.tag = sourceButtonItem.tag;

 #if MDC_AVAILABLE_SDK_IOS(13_0)
   if (@available(iOS 13.0, *)) {
     destinationButton.largeContentImageInsets = sourceButtonItem.largeContentSizeImageInsets;
   }
 #endif
 }

 - (void)updateButton:(UIButton *)button
             withItem:(UIBarButtonItem *)item
           barMetrics:(UIBarMetrics)barMetrics {
   [self updateButton:button withItem:item forState:UIControlStateNormal barMetrics:barMetrics];
   [self updateButton:button withItem:item forState:UIControlStateHighlighted barMetrics:barMetrics];
   [self updateButton:button withItem:item forState:UIControlStateDisabled barMetrics:barMetrics];
 }

 - (void)updateButton:(UIButton *)button
             withItem:(UIBarButtonItem *)item
             forState:(UIControlState)state
           barMetrics:(UIBarMetrics)barMetrics {
   NSString *title = item.title ? item.title : @"";
   if ([UIButton instancesRespondToSelector:@selector(setAttributedTitle:forState:)]) {
     NSMutableDictionary<NSString *, id> *attributes = [NSMutableDictionary dictionary];

     // UIBarButtonItem's appearance proxy values don't appear to come "for free" like they do with
     // typical UIView instances, so we're attempting to recreate the behavior here.
     NSArray *appearanceProxies = @ [[item.class appearance]];
     for (UIBarButtonItem *appearance in appearanceProxies) {
       [attributes addEntriesFromDictionary:[appearance titleTextAttributesForState:state]];
     }
     [attributes addEntriesFromDictionary:[item titleTextAttributesForState:state]];
     if ([attributes count] > 0) {
       [button setAttributedTitle:[[NSAttributedString alloc] initWithString:title
                                                                  attributes:attributes]
                         forState:state];
     }
   } else {
     [button setTitle:title forState:state];
   }

   UIImage *backgroundImage = [item backgroundImageForState:state barMetrics:barMetrics];
   if (backgroundImage) {
     [button setBackgroundImage:backgroundImage forState:state];
   }
 }

 - (void)transferCustomViewOwnershipForBarButtonItem:(UIBarButtonItem *)barButtonItem {
   UIView *customView = barButtonItem.customView;
   if (customView && ![customView isKindOfClass:[MDCButtonBarSandbagView class]]) {
     // Transfer ownership of any UIBarButtonItem.customView to the internal property
     // so that UINavigationController won't steal the view from us.
     barButtonItem.mdc_customView = customView;
     barButtonItem.customView = [[MDCButtonBarSandbagView alloc] init];
   }
 }

 @end

 @implementation MDCButtonBarSandbagView
 @end

 @implementation UIBarButtonItem (MDCHeaderInternal)

 @dynamic mdc_customView;

 - (UIView *)mdc_customView {
   return objc_getAssociatedObject(self, _cmd);
 }

 - (void)mdc_setCustomView:(UIView *)customView {
   objc_setAssociatedObject(self, @selector(mdc_customView), customView,
                            OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 }

 @end
	// Copyright 2016-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 "MDCAppBarButtonBarBuilder.h"

	#import <objc/runtime.h>
	#import "MaterialInk.h"

	#import "MaterialAvailability.h"
	#import "MDCButtonBar.h"
	#import "MDCButtonBarButton.h"
	#import "MDCButtonBar+Private.h"
	#import "MaterialButtons.h"

	// Additional insets for the left-most or right-most items.
	static const CGFloat kEdgeButtonAdditionalMargin = 4;

	// The default MDCButton's alpha for display state is 0.1 which in the context of bar buttons makes
	// it practically invisible. Setting button to a higher opacity is closer to what the button should
	// look like when it is disabled.
	static const CGFloat kDisabledButtonAlpha = (CGFloat)0.38;

	// Default content inset for buttons.
	static const UIEdgeInsets kButtonInset = {0, 12, 0, 12};

	// Indiana Jones style placeholder view for UINavigationBar. Ownership of UIBarButtonItem.customView
	// and UINavigationItem.titleView are normally transferred to UINavigationController but we plan to
	// steal them away. In order to avoid crashing during KVO updates, we steal the view away and
	// replace it with a sandbag view.
	@interface MDCButtonBarSandbagView : UIView
	@end

	@interface UIBarButtonItem (MDCHeaderInternal)

	// Internal version of the standard -customView property. When an item is pushed onto a
	// UINavigationController stack, any -customView object is moved over to this property. This
	// prevents UINavigationController from adding the customView to its own view hierarchy.
	@property(nonatomic, strong, setter=mdc_setCustomView:) UIView *mdc_customView;

	@end

	@implementation MDCAppBarButtonBarBuilder {
	NSMutableDictionary<NSNumber , UIFont > *_fonts;
	NSMutableDictionary<NSNumber , UIColor > *_titleColors;
	}

	- (instancetype)init {
	self = [super init];
	if (self) {
	_fonts = [NSMutableDictionary dictionary];
	_titleColors = [NSMutableDictionary dictionary];
	}
	return self;
	}

	- (nullable UIFont *)titleFontForState:(UIControlState)state {
	UIFont *font = _fonts[@(state)];
	if (!font && state != UIControlStateNormal) {
	font = _fonts[@(UIControlStateNormal)];
	}
	return font;
	}

	- (void)setTitleFont:(UIFont *)font forState:(UIControlState)state {
	_fonts[@(state)] = font;
	}

	- (UIColor *)titleColorForState:(UIControlState)state {
	UIColor *color = _titleColors[@(state)];
	if (!color && state != UIControlStateNormal) {
	color = _titleColors[@(UIControlStateNormal)];
	}
	return color;
	}

	- (void)setTitleColor:(UIColor *)color forState:(UIControlState)state {
	_titleColors[@(state)] = color;
	}

	- (void)updateTitleColorForButton:(UIButton )button withItem:(UIBarButtonItem )item {
	// Apply title colors to the button in order of descending priority (last one wins).

	// General buttonTitleColor (proxy for contextual tint color)
	[button setTitleColor:self.buttonTitleColor forState:UIControlStateNormal];

	// Explicit -setTitleColor:forState:
	for (NSNumber *state in _titleColors) {
	UIColor *color = _titleColors[state];
	[button setTitleColor:color forState:(UIControlState)state.intValue];
	}

	// The item's explicit tintColor
	if (item.tintColor) {
	[button setTitleColor:item.tintColor forState:UIControlStateNormal];
	}
	}

	#pragma mark - MDCBarButtonItemBuilding

	- (UIView )buttonBar:(MDCButtonBar )buttonBar
	viewForItem:(UIBarButtonItem *)buttonItem
	layoutHints:(MDCBarButtonItemLayoutHints)layoutHints {
	if (buttonItem == nil) {
	return nil;
	}

	// Transfer custom view ownership if necessary.
	[self transferCustomViewOwnershipForBarButtonItem:buttonItem];

	// Take the real custom view if it exists instead of sandbag view.
	UIView *customView =
	buttonItem.mdc_customView ? buttonItem.mdc_customView : buttonItem.customView;
	if (customView) {
	return customView;
	}

	// NOTE: This assertion does not occur in release builds because it is accessing a private api.
	#if DEBUG
	NSAssert(![[buttonItem valueForKey:@"isSystemItem"] boolValue],
	@"Instances of %@ must not be initialized with %@ when working with %@."
	@" This is because we cannot extract the system item type from the item.",
	NSStringFromClass([buttonItem class]),
	NSStringFromSelector(@selector(initWithBarButtonSystemItem:target:action:)),
	NSStringFromClass([MDCButtonBar class]));
	#endif

	#ifdef __IPHONE_14_0
	MDCButtonBarButton *button;
	if (@available(iOS 14.0, *)) {
	button = [MDCButtonBarButton buttonWithType:UIButtonTypeCustom
	primaryAction:buttonItem.primaryAction];
	} else {
	button = [[MDCButtonBarButton alloc] init];
	}
	#else
	MDCButtonBarButton *button = [[MDCButtonBarButton alloc] init];
	#endif
	[button setBackgroundColor:[UIColor clearColor] forState:UIControlStateNormal];
	button.disabledAlpha = kDisabledButtonAlpha;
	button.enableRippleBehavior = buttonBar.enableRippleBehavior;
	if (buttonBar.inkColor) {
	button.inkColor = buttonBar.inkColor;
	}

	button.exclusiveTouch = YES;

	[MDCAppBarButtonBarBuilder configureButton:button fromButtonItem:buttonItem];

	button.uppercaseTitle = buttonBar.uppercasesButtonTitles;
	[button setUnderlyingColorHint:self.buttonUnderlyingColor];
	for (NSNumber *state in _fonts) {
	UIFont *font = _fonts[state];
	[button setTitleFont:font forState:(UIControlState)state.intValue];
	}
	[self updateTitleColorForButton:button withItem:buttonItem];

	#if MDC_AVAILABLE_SDK_IOS(13_0)
	if (@available(iOS 13.0, *)) {
	button.largeContentImage = self.largeContentImage;
	button.largeContentTitle = self.largeContentTitle;
	}
	#endif

	[self updateButton:button withItem:buttonItem barMetrics:UIBarMetricsDefault];

	#ifdef __IPHONE_13_4
	if (@available(iOS 13.4, *)) {
	// Because some iOS 13 betas did not have the UIPointerInteraction class, we need to verify
	// that it exists before attempting to use it.
	if (NSClassFromString(@"UIPointerInteraction")) {
	UIPointerInteraction *pointerInteraction =
	[[UIPointerInteraction alloc] initWithDelegate:buttonBar];
	[button addInteraction:pointerInteraction];
	}
	}
	#endif

	// Contrary to intuition, UIKit provides the UIBarButtonItem as the action's first argument when
	// bar buttons are tapped, NOT the button itself. Simply adding the item's target/action to the
	// button does not allow us to pass the expected argument to the target.
	//
	// MDCButtonBar provides didTapButton:event: to which we can pass button events
	// so that the correct argument is ultimately passed along.
	[button addTarget:buttonBar
	action:@selector(didTapButton:event:)
	forControlEvents:UIControlEventTouchUpInside];
	#if MDC_AVAILABLE_SDK_IOS(14_0)
	if (@available(iOS 14.0, *)) {
	if (buttonItem.menu) {
	// Setting the menu as primary action will result in the target / action pair not being
	// called. Setting the primaryAction on a menu item will result in it not having a target /
	// action pair anymore and not taking a new one on until primaryAction is cleared again.
	button.menu = buttonItem.menu;
	if (!buttonItem.primaryAction) {
	button.showsMenuAsPrimaryAction = YES;
	}
	}
	}
	#endif

	UIEdgeInsets contentInsets = [MDCAppBarButtonBarBuilder
	contentInsetsForButton:button
	layoutPosition:buttonBar.layoutPosition
	layoutHints:layoutHints
	layoutDirection:[buttonBar effectiveUserInterfaceLayoutDirection]
	userInterfaceIdiom:[self usePadInsetsForButtonBar:buttonBar] ? UIUserInterfaceIdiomPad
	: UIUserInterfaceIdiomPhone];

	button.contentEdgeInsets = contentInsets;
	button.enabled = buttonItem.enabled;
	button.accessibilityLabel = buttonItem.accessibilityLabel;
	button.accessibilityHint = buttonItem.accessibilityHint;
	button.accessibilityValue = buttonItem.accessibilityValue;
	button.accessibilityIdentifier = buttonItem.accessibilityIdentifier;

	return button;
	}

	#pragma mark - Private

	// Used to determine whether or not to apply insets relevant for iPad or use smaller iPhone size
	// Because only widths are affected, we use horizontal size class
	- (BOOL)usePadInsetsForButtonBar:(MDCButtonBar *)buttonBar {
	const BOOL isPad = [[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad;
	if (isPad && buttonBar.traitCollection.horizontalSizeClass == UIUserInterfaceSizeClassRegular) {
	return YES;
	}
	return NO;
	}

	+ (UIEdgeInsets)contentInsetsForButton:(MDCButton *)button
	layoutPosition:(MDCButtonBarLayoutPosition)layoutPosition
	layoutHints:(MDCBarButtonItemLayoutHints)layoutHints
	layoutDirection:(UIUserInterfaceLayoutDirection)layoutDirection
	userInterfaceIdiom:(UIUserInterfaceIdiom)userInterfaceIdiom {
	UIEdgeInsets contentInsets = kButtonInset;
	if ([button currentImage] \|\| [button currentTitle].length) {
	CGFloat additionalInset = kEdgeButtonAdditionalMargin;
	BOOL isFirstButton = (layoutHints & MDCBarButtonItemLayoutHintsIsFirstButton) ==
	MDCBarButtonItemLayoutHintsIsFirstButton;
	BOOL isLastButton = (layoutHints & MDCBarButtonItemLayoutHintsIsLastButton) ==
	MDCBarButtonItemLayoutHintsIsLastButton;
	if (isFirstButton && layoutPosition == MDCButtonBarLayoutPositionLeading) {
	// Left-most button in LTR, and right-most button in RTL.
	if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
	contentInsets.left += additionalInset;
	} else {
	contentInsets.right += additionalInset;
	}
	} else if (isFirstButton && layoutPosition == MDCButtonBarLayoutPositionTrailing) {
	// Right-most button in LTR, and left-most button in RTL.
	if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
	contentInsets.right += additionalInset;
	} else {
	contentInsets.left += additionalInset;
	}
	}
	if (isLastButton && layoutPosition == MDCButtonBarLayoutPositionTrailing) {
	// Left-most button in LTR, and right-most button in RTL.
	if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
	contentInsets.left += additionalInset;
	} else {
	contentInsets.right += additionalInset;
	}
	} else if (isLastButton && layoutPosition == MDCButtonBarLayoutPositionLeading) {
	// Right-most button in LTR, and left-most button in RTL.
	if (layoutDirection == UIUserInterfaceLayoutDirectionLeftToRight) {
	contentInsets.right += additionalInset;
	} else {
	contentInsets.left += additionalInset;
	}
	}
	} else {
	NSAssert(0, @"No button title or image");
	}

	return contentInsets;
	}

	+ (void)configureButton:(MDCButton *)destinationButton
	fromButtonItem:(UIBarButtonItem *)sourceButtonItem {
	if (sourceButtonItem == nil \|\| destinationButton == nil) {
	return;
	}

	if (sourceButtonItem.title != nil) {
	[destinationButton setTitle:sourceButtonItem.title forState:UIControlStateNormal];
	}
	if (sourceButtonItem.image != nil) {
	[destinationButton setImage:sourceButtonItem.image forState:UIControlStateNormal];
	}
	if (sourceButtonItem.tintColor != nil) {
	destinationButton.tintColor = sourceButtonItem.tintColor;
	}

	if (sourceButtonItem.title) {
	destinationButton.inkStyle = MDCInkStyleBounded;
	} else {
	destinationButton.inkStyle = MDCInkStyleUnbounded;
	}

	destinationButton.tag = sourceButtonItem.tag;

	#if MDC_AVAILABLE_SDK_IOS(13_0)
	if (@available(iOS 13.0, *)) {
	destinationButton.largeContentImageInsets = sourceButtonItem.largeContentSizeImageInsets;
	}
	#endif
	}

	- (void)updateButton:(UIButton *)button
	withItem:(UIBarButtonItem *)item
	barMetrics:(UIBarMetrics)barMetrics {
	[self updateButton:button withItem:item forState:UIControlStateNormal barMetrics:barMetrics];
	[self updateButton:button withItem:item forState:UIControlStateHighlighted barMetrics:barMetrics];
	[self updateButton:button withItem:item forState:UIControlStateDisabled barMetrics:barMetrics];
	}

	- (void)updateButton:(UIButton *)button
	withItem:(UIBarButtonItem *)item
	forState:(UIControlState)state
	barMetrics:(UIBarMetrics)barMetrics {
	NSString *title = item.title ? item.title : @"";
	if ([UIButton instancesRespondToSelector:@selector(setAttributedTitle:forState:)]) {
	NSMutableDictionary<NSString , id> attributes = [NSMutableDictionary dictionary];

	// UIBarButtonItem's appearance proxy values don't appear to come "for free" like they do with
	// typical UIView instances, so we're attempting to recreate the behavior here.
	NSArray *appearanceProxies = @ [[item.class appearance]];
	for (UIBarButtonItem *appearance in appearanceProxies) {
	[attributes addEntriesFromDictionary:[appearance titleTextAttributesForState:state]];
	}
	[attributes addEntriesFromDictionary:[item titleTextAttributesForState:state]];
	if ([attributes count] > 0) {
	[button setAttributedTitle:[[NSAttributedString alloc] initWithString:title
	attributes:attributes]
	forState:state];
	}
	} else {
	[button setTitle:title forState:state];
	}

	UIImage *backgroundImage = [item backgroundImageForState:state barMetrics:barMetrics];
	if (backgroundImage) {
	[button setBackgroundImage:backgroundImage forState:state];
	}
	}

	- (void)transferCustomViewOwnershipForBarButtonItem:(UIBarButtonItem *)barButtonItem {
	UIView *customView = barButtonItem.customView;
	if (customView && ![customView isKindOfClass:[MDCButtonBarSandbagView class]]) {
	// Transfer ownership of any UIBarButtonItem.customView to the internal property
	// so that UINavigationController won't steal the view from us.
	barButtonItem.mdc_customView = customView;
	barButtonItem.customView = [[MDCButtonBarSandbagView alloc] init];
	}
	}

	@end

	@implementation MDCButtonBarSandbagView
	@end

	@implementation UIBarButtonItem (MDCHeaderInternal)

	@dynamic mdc_customView;

	- (UIView *)mdc_customView {
	return objc_getAssociatedObject(self, _cmd);
	}

	- (void)mdc_setCustomView:(UIView *)customView {
	objc_setAssociatedObject(self, @selector(mdc_customView), customView,
	OBJC_ASSOCIATION_RETAIN_NONATOMIC);
	}

	@end