components/TextControls/src/BaseTextAreas/MDCBaseTextArea.m - external/github.com/material-components/material-components-ios - Git at Google

 // Copyright 2020-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 "MDCBaseTextArea.h"

 #import <CoreGraphics/CoreGraphics.h>
 #import <MDFInternationalization/MDFInternationalization.h>
 #import <QuartzCore/QuartzCore.h>

 #import "MaterialMath.h"
 #import "MaterialTextControlsPrivate+BaseStyle.h"
 #import "MaterialTextControlsPrivate+Shared.h"
 #import "private/MDCBaseTextAreaLayout.h"
 #import "private/MDCBaseTextAreaTextView.h"

 static const CGFloat kMDCBaseTextAreaDefaultMinimumNumberOfVisibleLines = (CGFloat)2.0;
 static const CGFloat kMDCBaseTextAreaDefaultMaximumNumberOfVisibleLines = (CGFloat)4.0;

 @interface MDCBaseTextArea () <MDCTextControl,
                                MDCBaseTextAreaTextViewDelegate,
                                UIGestureRecognizerDelegate>

 #pragma mark MDCTextControl properties
 @property(strong, nonatomic) UILabel *label;
 @property(nonatomic, strong) MDCTextControlAssistiveLabelView *assistiveLabelView;
 @property(strong, nonatomic) MDCBaseTextAreaLayout *layout;
 @property(nonatomic, assign) MDCTextControlState textControlState;
 @property(nonatomic, assign) MDCTextControlLabelPosition labelPosition;
 @property(nonatomic, assign) CGRect labelFrame;
 @property(nonatomic, assign) NSTimeInterval animationDuration;

 @property(nonatomic, strong)
     NSMutableDictionary<NSNumber *, MDCTextControlColorViewModel *> *colorViewModels;

 @property(strong, nonatomic) UIView *maskedTextViewContainerView;
 @property(strong, nonatomic) MDCBaseTextAreaTextView *baseTextAreaTextView;

 @property(nonatomic, strong) MDCTextControlGradientManager *gradientManager;

 @property(strong, nonatomic) UITapGestureRecognizer *tapGesture;

 @end

 @implementation MDCBaseTextArea
 @synthesize containerStyle = _containerStyle;
 @synthesize assistiveLabelDrawPriority = _assistiveLabelDrawPriority;
 @synthesize customAssistiveLabelDrawPriority = _customAssistiveLabelDrawPriority;
 @synthesize preferredContainerHeight = _preferredContainerHeight;
 @synthesize adjustsFontForContentSizeCategory = _adjustsFontForContentSizeCategory;

 #pragma mark Object Lifecycle

 - (instancetype)initWithFrame:(CGRect)frame {
   self = [super initWithFrame:frame];
   if (self) {
     [self commonMDCBaseTextAreaInit];
   }
   return self;
 }

 - (instancetype)initWithCoder:(NSCoder *)aDecoder {
   self = [super initWithCoder:aDecoder];
   if (self) {
     [self commonMDCBaseTextAreaInit];
   }
   return self;
 }

 - (void)commonMDCBaseTextAreaInit {
   [self initializeProperties];
   [self setUpTapGesture];
   [self setUpColorViewModels];
   [self setUpLabel];
   [self setUpAssistiveLabels];
   [self setUpTextView];
   [self observeTextViewNotifications];
 }

 - (void)dealloc {
   [[NSNotificationCenter defaultCenter] removeObserver:self];
 }

 #pragma mark Setup

 - (void)initializeProperties {
   self.animationDuration = kMDCTextControlDefaultAnimationDuration;
   self.labelBehavior = MDCTextControlLabelBehaviorFloats;
   self.labelPosition = [self determineCurrentLabelPosition];
   self.textControlState = [self determineCurrentTextControlState];
   self.containerStyle = [[MDCTextControlStyleBase alloc] init];
   self.colorViewModels = [[NSMutableDictionary alloc] init];
   self.minimumNumberOfVisibleRows = kMDCBaseTextAreaDefaultMinimumNumberOfVisibleLines;
   self.maximumNumberOfVisibleRows = kMDCBaseTextAreaDefaultMaximumNumberOfVisibleLines;
   self.gradientManager = [[MDCTextControlGradientManager alloc] init];
 }

 - (void)setUpTapGesture {
   self.tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                             action:@selector(handleTap:)];
   [self addGestureRecognizer:self.tapGesture];
 }

 - (void)setUpColorViewModels {
   self.colorViewModels = [[NSMutableDictionary alloc] init];
   self.colorViewModels[@(MDCTextControlStateNormal)] =
       [[MDCTextControlColorViewModel alloc] initWithState:MDCTextControlStateNormal];
   self.colorViewModels[@(MDCTextControlStateEditing)] =
       [[MDCTextControlColorViewModel alloc] initWithState:MDCTextControlStateEditing];
   self.colorViewModels[@(MDCTextControlStateDisabled)] =
       [[MDCTextControlColorViewModel alloc] initWithState:MDCTextControlStateDisabled];
 }

 - (void)setUpAssistiveLabels {
   self.assistiveLabelDrawPriority = MDCTextControlAssistiveLabelDrawPriorityTrailing;
   self.assistiveLabelView = [[MDCTextControlAssistiveLabelView alloc] init];
   [self addSubview:self.assistiveLabelView];
 }

 - (void)setUpLabel {
   self.label = [[UILabel alloc] init];
   [self addSubview:self.label];
 }

 - (void)setUpTextView {
   self.maskedTextViewContainerView = [[UIView alloc] init];
   [self addSubview:self.maskedTextViewContainerView];

   self.baseTextAreaTextView = [[MDCBaseTextAreaTextView alloc] init];
   self.baseTextAreaTextView.textAreaTextViewDelegate = self;
   [self.maskedTextViewContainerView addSubview:self.baseTextAreaTextView];
 }

 #pragma mark UIView Overrides

 - (void)layoutSubviews {
   [self preLayoutSubviews];
   [super layoutSubviews];
   [self postLayoutSubviews];
 }

 - (CGSize)sizeThatFits:(CGSize)size {
   return [self preferredSizeWithWidth:size.width];
 }

 - (CGSize)intrinsicContentSize {
   return [self preferredSizeWithWidth:CGRectGetWidth(self.bounds)];
 }

 - (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection {
   [super traitCollectionDidChange:previousTraitCollection];
   [self setNeedsLayout];
 }

 - (void)setSemanticContentAttribute:(UISemanticContentAttribute)semanticContentAttribute {
   [super setSemanticContentAttribute:semanticContentAttribute];
   [self setNeedsLayout];
 }

 - (void)setEnabled:(BOOL)enabled {
   [super setEnabled:enabled];
   self.textView.editable = enabled;
   [self setNeedsLayout];
 }

 #pragma mark Private Layout

 - (void)preLayoutSubviews {
   self.textControlState = [self determineCurrentTextControlState];
   self.labelPosition = [self determineCurrentLabelPosition];
   MDCTextControlColorViewModel *colorViewModel =
       [self textControlColorViewModelForState:self.textControlState];
   [self applyColorViewModel:colorViewModel withLabelPosition:self.labelPosition];
   CGSize fittingSize = CGSizeMake(CGRectGetWidth(self.frame), CGFLOAT_MAX);
   self.layout = [self calculateLayoutWithSize:fittingSize];
   self.labelFrame = [self.layout labelFrameWithLabelPosition:self.labelPosition];
 }

 - (void)postLayoutSubviews {
   self.maskedTextViewContainerView.frame = self.containerFrame;
   self.textView.frame = self.layout.textViewFrame;
   self.assistiveLabelView.frame = self.layout.assistiveLabelViewFrame;
   self.assistiveLabelView.layout = self.layout.assistiveLabelViewLayout;
   [self.assistiveLabelView setNeedsLayout];
   [self animateLabel];
   [self.containerStyle applyStyleToTextControl:self animationDuration:self.animationDuration];
   [self layoutGradientLayers];
   [self.textView scrollRangeToVisible:self.textView.selectedRange];
 }

 - (MDCBaseTextAreaLayout *)calculateLayoutWithSize:(CGSize)size {
   CGFloat clampedCustomAssistiveLabelDrawPriority =
       [self clampedCustomAssistiveLabelDrawPriority:self.customAssistiveLabelDrawPriority];
   id<MDCTextControlVerticalPositioningReference> positioningReference =
       [self createPositioningReference];
   return [[MDCBaseTextAreaLayout alloc] initWithSize:size
                                 positioningReference:positioningReference
                                                 text:self.baseTextAreaTextView.text
                                                 font:self.normalFont
                                         floatingFont:self.floatingFont
                                                label:self.label
                                        labelPosition:self.labelPosition
                                        labelBehavior:self.labelBehavior
                                leadingAssistiveLabel:self.assistiveLabelView.leadingAssistiveLabel
                               trailingAssistiveLabel:self.assistiveLabelView.trailingAssistiveLabel
                           assistiveLabelDrawPriority:self.assistiveLabelDrawPriority
                     customAssistiveLabelDrawPriority:clampedCustomAssistiveLabelDrawPriority
                                                isRTL:self.shouldLayoutForRTL
                                            isEditing:self.textView.isFirstResponder];
 }

 - (id<MDCTextControlVerticalPositioningReference>)createPositioningReference {
   return [self.containerStyle
       positioningReferenceWithFloatingFontLineHeight:self.floatingFont.lineHeight
                                 normalFontLineHeight:self.normalFont.lineHeight
                                        textRowHeight:(self.normalFont.lineHeight +
                                                       self.normalFont.leading)
                                     numberOfTextRows:self.numberOfLinesOfVisibleText
                                              density:0
                             preferredContainerHeight:self.preferredContainerHeight];
 }

 - (CGFloat)clampedCustomAssistiveLabelDrawPriority:(CGFloat)customPriority {
   CGFloat value = customPriority;
   if (value < 0) {
     value = 0;
   } else if (value > 1) {
     value = 1;
   }
   return value;
 }

 - (CGSize)preferredSizeWithWidth:(CGFloat)width {
   CGSize fittingSize = CGSizeMake(width, CGFLOAT_MAX);
   MDCBaseTextAreaLayout *layout = [self calculateLayoutWithSize:fittingSize];
   return CGSizeMake(width, layout.calculatedHeight);
 }

 - (void)layoutGradientLayers {
   CGRect gradientLayerFrame = self.containerFrame;
   self.gradientManager.horizontalGradient.frame = gradientLayerFrame;
   self.gradientManager.verticalGradient.frame = gradientLayerFrame;
   self.gradientManager.horizontalGradient.locations = self.layout.horizontalGradientLocations;
   self.gradientManager.verticalGradient.locations = self.layout.verticalGradientLocations;
   self.maskedTextViewContainerView.layer.mask = [self.gradientManager combinedGradientMaskLayer];
 }

 - (CGFloat)numberOfLinesOfText {
   CGSize fittingSize = CGSizeMake(CGRectGetWidth(self.textView.bounds), CGFLOAT_MAX);
   NSDictionary *attributes = @{NSFontAttributeName : self.textView.font};
   CGRect boundingRect =
       [self.textView.text boundingRectWithSize:fittingSize
                                        options:NSStringDrawingUsesLineFragmentOrigin
                                     attributes:attributes
                                        context:nil];
   return MDCRound(CGRectGetHeight(boundingRect) / self.normalFont.lineHeight);
 }

 - (CGFloat)numberOfLinesOfVisibleText {
   CGFloat numberOfLinesOfText = [self numberOfLinesOfText];
   if (numberOfLinesOfText < self.minimumNumberOfVisibleRows) {
     return self.minimumNumberOfVisibleRows;
   } else if (numberOfLinesOfText > self.maximumNumberOfVisibleRows) {
     return self.maximumNumberOfVisibleRows;
   }
   return numberOfLinesOfText;
 }

 #pragma mark Dynamic Type

 - (void)setAdjustsFontForContentSizeCategory:(BOOL)adjustsFontForContentSizeCategory {
   if (@available(iOS 10.0, *)) {
     _adjustsFontForContentSizeCategory = adjustsFontForContentSizeCategory;
     self.textView.adjustsFontForContentSizeCategory = adjustsFontForContentSizeCategory;
     self.leadingAssistiveLabel.adjustsFontForContentSizeCategory =
         adjustsFontForContentSizeCategory;
     self.trailingAssistiveLabel.adjustsFontForContentSizeCategory =
         adjustsFontForContentSizeCategory;
   }
 }

 #pragma mark MDCTextControlState

 - (MDCTextControlState)determineCurrentTextControlState {
   BOOL isEnabled = self.enabled && self.baseTextAreaTextView.isEditable;
   BOOL isEditing = self.textView.isFirstResponder;
   return MDCTextControlStateWith(isEnabled, isEditing);
 }

 #pragma mark Label

 - (void)animateLabel {
   __weak MDCBaseTextArea *weakSelf = self;
   [MDCTextControlLabelAnimation animateLabel:self.label
                                        state:self.labelPosition
                             normalLabelFrame:self.layout.labelFrameNormal
                           floatingLabelFrame:self.layout.labelFrameFloating
                                   normalFont:self.normalFont
                                 floatingFont:self.floatingFont
                            animationDuration:self.animationDuration
                                   completion:^(BOOL finished) {
                                     if (finished) {
                                       // Ensure that the label position is correct in case of
                                       // competing animations.
                                       weakSelf.label.frame = weakSelf.labelFrame;
                                     }
                                   }];
 }

 - (BOOL)canLabelFloat {
   return self.labelBehavior == MDCTextControlLabelBehaviorFloats;
 }

 - (MDCTextControlLabelPosition)determineCurrentLabelPosition {
   return MDCTextControlLabelPositionWith(self.label.text.length > 0, self.textView.text.length > 0,
                                          self.canLabelFloat, self.textView.isFirstResponder);
 }

 #pragma mark Custom Accessors

 - (UITextView *)textView {
   return self.baseTextAreaTextView;
 }

 #pragma mark MDCTextControl Protocol Accessors

 - (void)setContainerStyle:(id<MDCTextControlStyle>)containerStyle {
   id<MDCTextControlStyle> oldStyle = _containerStyle;
   if (oldStyle) {
     [oldStyle removeStyleFrom:self];
   }
   _containerStyle = containerStyle;
   [_containerStyle applyStyleToTextControl:self animationDuration:self.animationDuration];
 }

 - (CGRect)containerFrame {
   return CGRectMake(0, 0, CGRectGetWidth(self.frame), self.layout.containerHeight);
 }

 - (UILabel *)leadingAssistiveLabel {
   return self.assistiveLabelView.leadingAssistiveLabel;
 }

 - (UILabel *)trailingAssistiveLabel {
   return self.assistiveLabelView.trailingAssistiveLabel;
 }

 #pragma mark Fonts

 - (UIFont *)normalFont {
   return self.baseTextAreaTextView.font ?: MDCTextControlDefaultUITextFieldFont();
 }

 - (UIFont *)floatingFont {
   return [self.containerStyle floatingFontWithNormalFont:self.normalFont];
 }

 #pragma mark MDCBaseTextAreaTextViewDelegate

 - (void)textAreaTextView:(MDCBaseTextAreaTextView *)textView
     willBecomeFirstResponder:(BOOL)willBecome {
   if (textView == self.baseTextAreaTextView) {
     [self setNeedsLayout];
   }
 }

 - (void)textAreaTextView:(MDCBaseTextAreaTextView *)textView
     willResignFirstResponder:(BOOL)willResign {
   if (textView == self.baseTextAreaTextView) {
     [self setNeedsLayout];
   }
 }

 #pragma mark Internationalization

 - (BOOL)shouldLayoutForRTL {
   if (self.semanticContentAttribute == UISemanticContentAttributeForceRightToLeft) {
     return YES;
   } else if (self.semanticContentAttribute == UISemanticContentAttributeForceLeftToRight) {
     return NO;
   } else {
     return self.mdf_effectiveUserInterfaceLayoutDirection ==
            UIUserInterfaceLayoutDirectionRightToLeft;
   }
 }

 #pragma mark Coloring

 - (void)applyColorViewModel:(MDCTextControlColorViewModel *)colorViewModel
           withLabelPosition:(MDCTextControlLabelPosition)labelPosition {
   UIColor *labelColor = [UIColor clearColor];
   if (labelPosition == MDCTextControlLabelPositionNormal) {
     labelColor = colorViewModel.normalLabelColor;
   } else if (labelPosition == MDCTextControlLabelPositionFloating) {
     labelColor = colorViewModel.floatingLabelColor;
   }
   self.textView.textColor = colorViewModel.textColor;
   self.leadingAssistiveLabel.textColor = colorViewModel.leadingAssistiveLabelColor;
   self.trailingAssistiveLabel.textColor = colorViewModel.trailingAssistiveLabelColor;
   self.label.textColor = labelColor;
 }

 - (void)setTextControlColorViewModel:(MDCTextControlColorViewModel *)TextControlColorViewModel
                             forState:(MDCTextControlState)textControlState {
   self.colorViewModels[@(textControlState)] = TextControlColorViewModel;
 }

 - (MDCTextControlColorViewModel *)textControlColorViewModelForState:
     (MDCTextControlState)textControlState {
   MDCTextControlColorViewModel *colorViewModel = self.colorViewModels[@(textControlState)];
   if (!colorViewModel) {
     colorViewModel = [[MDCTextControlColorViewModel alloc] initWithState:textControlState];
   }
   return colorViewModel;
 }

 #pragma mark Color Accessors

 - (void)setNormalLabelColor:(nonnull UIColor *)labelColor forState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   colorViewModel.normalLabelColor = labelColor;
   [self setNeedsLayout];
 }

 - (UIColor *)normalLabelColorForState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   return colorViewModel.normalLabelColor;
 }

 - (void)setFloatingLabelColor:(nonnull UIColor *)labelColor forState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   colorViewModel.floatingLabelColor = labelColor;
   [self setNeedsLayout];
 }

 - (UIColor *)floatingLabelColorForState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   return colorViewModel.floatingLabelColor;
 }

 - (void)setTextColor:(nonnull UIColor *)labelColor forState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   colorViewModel.textColor = labelColor;
   [self setNeedsLayout];
 }

 - (UIColor *)textColorForState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   return colorViewModel.textColor;
 }

 - (void)setLeadingAssistiveLabelColor:(nonnull UIColor *)assistiveLabelColor
                              forState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   colorViewModel.leadingAssistiveLabelColor = assistiveLabelColor;
   [self setNeedsLayout];
 }

 - (UIColor *)leadingAssistiveLabelColorForState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   return colorViewModel.leadingAssistiveLabelColor;
 }

 - (void)setTrailingAssistiveLabelColor:(nonnull UIColor *)assistiveLabelColor
                               forState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   colorViewModel.trailingAssistiveLabelColor = assistiveLabelColor;
   [self setNeedsLayout];
 }

 - (UIColor *)trailingAssistiveLabelColorForState:(MDCTextControlState)state {
   MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
   return colorViewModel.trailingAssistiveLabelColor;
 }

 #pragma mark User Actions

 - (void)handleTap:(UITapGestureRecognizer *)tap {
   if (tap.state == UIGestureRecognizerStateEnded) {
     if (!self.textView.isFirstResponder) {
       [self.textView becomeFirstResponder];
     }
   }
 }

 - (void)textViewChanged:(NSNotification *)notification {
   if (notification.object == self.baseTextAreaTextView) {
     [self setNeedsLayout];
   }
 }

 #pragma mark Notifications

 - (void)observeTextViewNotifications {
   [[NSNotificationCenter defaultCenter] addObserver:self
                                            selector:@selector(textViewChanged:)
                                                name:UITextViewTextDidChangeNotification
                                              object:nil];
 }

 @end
	// Copyright 2020-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 "MDCBaseTextArea.h"

	#import <CoreGraphics/CoreGraphics.h>
	#import <MDFInternationalization/MDFInternationalization.h>
	#import <QuartzCore/QuartzCore.h>

	#import "MaterialMath.h"
	#import "MaterialTextControlsPrivate+BaseStyle.h"
	#import "MaterialTextControlsPrivate+Shared.h"
	#import "private/MDCBaseTextAreaLayout.h"
	#import "private/MDCBaseTextAreaTextView.h"

	static const CGFloat kMDCBaseTextAreaDefaultMinimumNumberOfVisibleLines = (CGFloat)2.0;
	static const CGFloat kMDCBaseTextAreaDefaultMaximumNumberOfVisibleLines = (CGFloat)4.0;

	@interface MDCBaseTextArea () <MDCTextControl,
	MDCBaseTextAreaTextViewDelegate,
	UIGestureRecognizerDelegate>

	#pragma mark MDCTextControl properties
	@property(strong, nonatomic) UILabel *label;
	@property(nonatomic, strong) MDCTextControlAssistiveLabelView *assistiveLabelView;
	@property(strong, nonatomic) MDCBaseTextAreaLayout *layout;
	@property(nonatomic, assign) MDCTextControlState textControlState;
	@property(nonatomic, assign) MDCTextControlLabelPosition labelPosition;
	@property(nonatomic, assign) CGRect labelFrame;
	@property(nonatomic, assign) NSTimeInterval animationDuration;

	@property(nonatomic, strong)
	NSMutableDictionary<NSNumber , MDCTextControlColorViewModel > *colorViewModels;

	@property(strong, nonatomic) UIView *maskedTextViewContainerView;
	@property(strong, nonatomic) MDCBaseTextAreaTextView *baseTextAreaTextView;

	@property(nonatomic, strong) MDCTextControlGradientManager *gradientManager;

	@property(strong, nonatomic) UITapGestureRecognizer *tapGesture;

	@end

	@implementation MDCBaseTextArea
	@synthesize containerStyle = _containerStyle;
	@synthesize assistiveLabelDrawPriority = _assistiveLabelDrawPriority;
	@synthesize customAssistiveLabelDrawPriority = _customAssistiveLabelDrawPriority;
	@synthesize preferredContainerHeight = _preferredContainerHeight;
	@synthesize adjustsFontForContentSizeCategory = _adjustsFontForContentSizeCategory;

	#pragma mark Object Lifecycle

	- (instancetype)initWithFrame:(CGRect)frame {
	self = [super initWithFrame:frame];
	if (self) {
	[self commonMDCBaseTextAreaInit];
	}
	return self;
	}

	- (instancetype)initWithCoder:(NSCoder *)aDecoder {
	self = [super initWithCoder:aDecoder];
	if (self) {
	[self commonMDCBaseTextAreaInit];
	}
	return self;
	}

	- (void)commonMDCBaseTextAreaInit {
	[self initializeProperties];
	[self setUpTapGesture];
	[self setUpColorViewModels];
	[self setUpLabel];
	[self setUpAssistiveLabels];
	[self setUpTextView];
	[self observeTextViewNotifications];
	}

	- (void)dealloc {
	[[NSNotificationCenter defaultCenter] removeObserver:self];
	}

	#pragma mark Setup

	- (void)initializeProperties {
	self.animationDuration = kMDCTextControlDefaultAnimationDuration;
	self.labelBehavior = MDCTextControlLabelBehaviorFloats;
	self.labelPosition = [self determineCurrentLabelPosition];
	self.textControlState = [self determineCurrentTextControlState];
	self.containerStyle = [[MDCTextControlStyleBase alloc] init];
	self.colorViewModels = [[NSMutableDictionary alloc] init];
	self.minimumNumberOfVisibleRows = kMDCBaseTextAreaDefaultMinimumNumberOfVisibleLines;
	self.maximumNumberOfVisibleRows = kMDCBaseTextAreaDefaultMaximumNumberOfVisibleLines;
	self.gradientManager = [[MDCTextControlGradientManager alloc] init];
	}

	- (void)setUpTapGesture {
	self.tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self
	action:@selector(handleTap:)];
	[self addGestureRecognizer:self.tapGesture];
	}

	- (void)setUpColorViewModels {
	self.colorViewModels = [[NSMutableDictionary alloc] init];
	self.colorViewModels[@(MDCTextControlStateNormal)] =
	[[MDCTextControlColorViewModel alloc] initWithState:MDCTextControlStateNormal];
	self.colorViewModels[@(MDCTextControlStateEditing)] =
	[[MDCTextControlColorViewModel alloc] initWithState:MDCTextControlStateEditing];
	self.colorViewModels[@(MDCTextControlStateDisabled)] =
	[[MDCTextControlColorViewModel alloc] initWithState:MDCTextControlStateDisabled];
	}

	- (void)setUpAssistiveLabels {
	self.assistiveLabelDrawPriority = MDCTextControlAssistiveLabelDrawPriorityTrailing;
	self.assistiveLabelView = [[MDCTextControlAssistiveLabelView alloc] init];
	[self addSubview:self.assistiveLabelView];
	}

	- (void)setUpLabel {
	self.label = [[UILabel alloc] init];
	[self addSubview:self.label];
	}

	- (void)setUpTextView {
	self.maskedTextViewContainerView = [[UIView alloc] init];
	[self addSubview:self.maskedTextViewContainerView];

	self.baseTextAreaTextView = [[MDCBaseTextAreaTextView alloc] init];
	self.baseTextAreaTextView.textAreaTextViewDelegate = self;
	[self.maskedTextViewContainerView addSubview:self.baseTextAreaTextView];
	}

	#pragma mark UIView Overrides

	- (void)layoutSubviews {
	[self preLayoutSubviews];
	[super layoutSubviews];
	[self postLayoutSubviews];
	}

	- (CGSize)sizeThatFits:(CGSize)size {
	return [self preferredSizeWithWidth:size.width];
	}

	- (CGSize)intrinsicContentSize {
	return [self preferredSizeWithWidth:CGRectGetWidth(self.bounds)];
	}

	- (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection {
	[super traitCollectionDidChange:previousTraitCollection];
	[self setNeedsLayout];
	}

	- (void)setSemanticContentAttribute:(UISemanticContentAttribute)semanticContentAttribute {
	[super setSemanticContentAttribute:semanticContentAttribute];
	[self setNeedsLayout];
	}

	- (void)setEnabled:(BOOL)enabled {
	[super setEnabled:enabled];
	self.textView.editable = enabled;
	[self setNeedsLayout];
	}

	#pragma mark Private Layout

	- (void)preLayoutSubviews {
	self.textControlState = [self determineCurrentTextControlState];
	self.labelPosition = [self determineCurrentLabelPosition];
	MDCTextControlColorViewModel *colorViewModel =
	[self textControlColorViewModelForState:self.textControlState];
	[self applyColorViewModel:colorViewModel withLabelPosition:self.labelPosition];
	CGSize fittingSize = CGSizeMake(CGRectGetWidth(self.frame), CGFLOAT_MAX);
	self.layout = [self calculateLayoutWithSize:fittingSize];
	self.labelFrame = [self.layout labelFrameWithLabelPosition:self.labelPosition];
	}

	- (void)postLayoutSubviews {
	self.maskedTextViewContainerView.frame = self.containerFrame;
	self.textView.frame = self.layout.textViewFrame;
	self.assistiveLabelView.frame = self.layout.assistiveLabelViewFrame;
	self.assistiveLabelView.layout = self.layout.assistiveLabelViewLayout;
	[self.assistiveLabelView setNeedsLayout];
	[self animateLabel];
	[self.containerStyle applyStyleToTextControl:self animationDuration:self.animationDuration];
	[self layoutGradientLayers];
	[self.textView scrollRangeToVisible:self.textView.selectedRange];
	}

	- (MDCBaseTextAreaLayout *)calculateLayoutWithSize:(CGSize)size {
	CGFloat clampedCustomAssistiveLabelDrawPriority =
	[self clampedCustomAssistiveLabelDrawPriority:self.customAssistiveLabelDrawPriority];
	id<MDCTextControlVerticalPositioningReference> positioningReference =
	[self createPositioningReference];
	return [[MDCBaseTextAreaLayout alloc] initWithSize:size
	positioningReference:positioningReference
	text:self.baseTextAreaTextView.text
	font:self.normalFont
	floatingFont:self.floatingFont
	label:self.label
	labelPosition:self.labelPosition
	labelBehavior:self.labelBehavior
	leadingAssistiveLabel:self.assistiveLabelView.leadingAssistiveLabel
	trailingAssistiveLabel:self.assistiveLabelView.trailingAssistiveLabel
	assistiveLabelDrawPriority:self.assistiveLabelDrawPriority
	customAssistiveLabelDrawPriority:clampedCustomAssistiveLabelDrawPriority
	isRTL:self.shouldLayoutForRTL
	isEditing:self.textView.isFirstResponder];
	}

	- (id<MDCTextControlVerticalPositioningReference>)createPositioningReference {
	return [self.containerStyle
	positioningReferenceWithFloatingFontLineHeight:self.floatingFont.lineHeight
	normalFontLineHeight:self.normalFont.lineHeight
	textRowHeight:(self.normalFont.lineHeight +
	self.normalFont.leading)
	numberOfTextRows:self.numberOfLinesOfVisibleText
	density:0
	preferredContainerHeight:self.preferredContainerHeight];
	}

	- (CGFloat)clampedCustomAssistiveLabelDrawPriority:(CGFloat)customPriority {
	CGFloat value = customPriority;
	if (value < 0) {
	value = 0;
	} else if (value > 1) {
	value = 1;
	}
	return value;
	}

	- (CGSize)preferredSizeWithWidth:(CGFloat)width {
	CGSize fittingSize = CGSizeMake(width, CGFLOAT_MAX);
	MDCBaseTextAreaLayout *layout = [self calculateLayoutWithSize:fittingSize];
	return CGSizeMake(width, layout.calculatedHeight);
	}

	- (void)layoutGradientLayers {
	CGRect gradientLayerFrame = self.containerFrame;
	self.gradientManager.horizontalGradient.frame = gradientLayerFrame;
	self.gradientManager.verticalGradient.frame = gradientLayerFrame;
	self.gradientManager.horizontalGradient.locations = self.layout.horizontalGradientLocations;
	self.gradientManager.verticalGradient.locations = self.layout.verticalGradientLocations;
	self.maskedTextViewContainerView.layer.mask = [self.gradientManager combinedGradientMaskLayer];
	}

	- (CGFloat)numberOfLinesOfText {
	CGSize fittingSize = CGSizeMake(CGRectGetWidth(self.textView.bounds), CGFLOAT_MAX);
	NSDictionary *attributes = @{NSFontAttributeName : self.textView.font};
	CGRect boundingRect =
	[self.textView.text boundingRectWithSize:fittingSize
	options:NSStringDrawingUsesLineFragmentOrigin
	attributes:attributes
	context:nil];
	return MDCRound(CGRectGetHeight(boundingRect) / self.normalFont.lineHeight);
	}

	- (CGFloat)numberOfLinesOfVisibleText {
	CGFloat numberOfLinesOfText = [self numberOfLinesOfText];
	if (numberOfLinesOfText < self.minimumNumberOfVisibleRows) {
	return self.minimumNumberOfVisibleRows;
	} else if (numberOfLinesOfText > self.maximumNumberOfVisibleRows) {
	return self.maximumNumberOfVisibleRows;
	}
	return numberOfLinesOfText;
	}

	#pragma mark Dynamic Type

	- (void)setAdjustsFontForContentSizeCategory:(BOOL)adjustsFontForContentSizeCategory {
	if (@available(iOS 10.0, *)) {
	_adjustsFontForContentSizeCategory = adjustsFontForContentSizeCategory;
	self.textView.adjustsFontForContentSizeCategory = adjustsFontForContentSizeCategory;
	self.leadingAssistiveLabel.adjustsFontForContentSizeCategory =
	adjustsFontForContentSizeCategory;
	self.trailingAssistiveLabel.adjustsFontForContentSizeCategory =
	adjustsFontForContentSizeCategory;
	}
	}

	#pragma mark MDCTextControlState

	- (MDCTextControlState)determineCurrentTextControlState {
	BOOL isEnabled = self.enabled && self.baseTextAreaTextView.isEditable;
	BOOL isEditing = self.textView.isFirstResponder;
	return MDCTextControlStateWith(isEnabled, isEditing);
	}

	#pragma mark Label

	- (void)animateLabel {
	__weak MDCBaseTextArea *weakSelf = self;
	[MDCTextControlLabelAnimation animateLabel:self.label
	state:self.labelPosition
	normalLabelFrame:self.layout.labelFrameNormal
	floatingLabelFrame:self.layout.labelFrameFloating
	normalFont:self.normalFont
	floatingFont:self.floatingFont
	animationDuration:self.animationDuration
	completion:^(BOOL finished) {
	if (finished) {
	// Ensure that the label position is correct in case of
	// competing animations.
	weakSelf.label.frame = weakSelf.labelFrame;
	}
	}];
	}

	- (BOOL)canLabelFloat {
	return self.labelBehavior == MDCTextControlLabelBehaviorFloats;
	}

	- (MDCTextControlLabelPosition)determineCurrentLabelPosition {
	return MDCTextControlLabelPositionWith(self.label.text.length > 0, self.textView.text.length > 0,
	self.canLabelFloat, self.textView.isFirstResponder);
	}

	#pragma mark Custom Accessors

	- (UITextView *)textView {
	return self.baseTextAreaTextView;
	}

	#pragma mark MDCTextControl Protocol Accessors

	- (void)setContainerStyle:(id<MDCTextControlStyle>)containerStyle {
	id<MDCTextControlStyle> oldStyle = _containerStyle;
	if (oldStyle) {
	[oldStyle removeStyleFrom:self];
	}
	_containerStyle = containerStyle;
	[_containerStyle applyStyleToTextControl:self animationDuration:self.animationDuration];
	}

	- (CGRect)containerFrame {
	return CGRectMake(0, 0, CGRectGetWidth(self.frame), self.layout.containerHeight);
	}

	- (UILabel *)leadingAssistiveLabel {
	return self.assistiveLabelView.leadingAssistiveLabel;
	}

	- (UILabel *)trailingAssistiveLabel {
	return self.assistiveLabelView.trailingAssistiveLabel;
	}

	#pragma mark Fonts

	- (UIFont *)normalFont {
	return self.baseTextAreaTextView.font ?: MDCTextControlDefaultUITextFieldFont();
	}

	- (UIFont *)floatingFont {
	return [self.containerStyle floatingFontWithNormalFont:self.normalFont];
	}

	#pragma mark MDCBaseTextAreaTextViewDelegate

	- (void)textAreaTextView:(MDCBaseTextAreaTextView *)textView
	willBecomeFirstResponder:(BOOL)willBecome {
	if (textView == self.baseTextAreaTextView) {
	[self setNeedsLayout];
	}
	}

	- (void)textAreaTextView:(MDCBaseTextAreaTextView *)textView
	willResignFirstResponder:(BOOL)willResign {
	if (textView == self.baseTextAreaTextView) {
	[self setNeedsLayout];
	}
	}

	#pragma mark Internationalization

	- (BOOL)shouldLayoutForRTL {
	if (self.semanticContentAttribute == UISemanticContentAttributeForceRightToLeft) {
	return YES;
	} else if (self.semanticContentAttribute == UISemanticContentAttributeForceLeftToRight) {
	return NO;
	} else {
	return self.mdf_effectiveUserInterfaceLayoutDirection ==
	UIUserInterfaceLayoutDirectionRightToLeft;
	}
	}

	#pragma mark Coloring

	- (void)applyColorViewModel:(MDCTextControlColorViewModel *)colorViewModel
	withLabelPosition:(MDCTextControlLabelPosition)labelPosition {
	UIColor *labelColor = [UIColor clearColor];
	if (labelPosition == MDCTextControlLabelPositionNormal) {
	labelColor = colorViewModel.normalLabelColor;
	} else if (labelPosition == MDCTextControlLabelPositionFloating) {
	labelColor = colorViewModel.floatingLabelColor;
	}
	self.textView.textColor = colorViewModel.textColor;
	self.leadingAssistiveLabel.textColor = colorViewModel.leadingAssistiveLabelColor;
	self.trailingAssistiveLabel.textColor = colorViewModel.trailingAssistiveLabelColor;
	self.label.textColor = labelColor;
	}

	- (void)setTextControlColorViewModel:(MDCTextControlColorViewModel *)TextControlColorViewModel
	forState:(MDCTextControlState)textControlState {
	self.colorViewModels[@(textControlState)] = TextControlColorViewModel;
	}

	- (MDCTextControlColorViewModel *)textControlColorViewModelForState:
	(MDCTextControlState)textControlState {
	MDCTextControlColorViewModel *colorViewModel = self.colorViewModels[@(textControlState)];
	if (!colorViewModel) {
	colorViewModel = [[MDCTextControlColorViewModel alloc] initWithState:textControlState];
	}
	return colorViewModel;
	}

	#pragma mark Color Accessors

	- (void)setNormalLabelColor:(nonnull UIColor *)labelColor forState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	colorViewModel.normalLabelColor = labelColor;
	[self setNeedsLayout];
	}

	- (UIColor *)normalLabelColorForState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	return colorViewModel.normalLabelColor;
	}

	- (void)setFloatingLabelColor:(nonnull UIColor *)labelColor forState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	colorViewModel.floatingLabelColor = labelColor;
	[self setNeedsLayout];
	}

	- (UIColor *)floatingLabelColorForState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	return colorViewModel.floatingLabelColor;
	}

	- (void)setTextColor:(nonnull UIColor *)labelColor forState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	colorViewModel.textColor = labelColor;
	[self setNeedsLayout];
	}

	- (UIColor *)textColorForState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	return colorViewModel.textColor;
	}

	- (void)setLeadingAssistiveLabelColor:(nonnull UIColor *)assistiveLabelColor
	forState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	colorViewModel.leadingAssistiveLabelColor = assistiveLabelColor;
	[self setNeedsLayout];
	}

	- (UIColor *)leadingAssistiveLabelColorForState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	return colorViewModel.leadingAssistiveLabelColor;
	}

	- (void)setTrailingAssistiveLabelColor:(nonnull UIColor *)assistiveLabelColor
	forState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	colorViewModel.trailingAssistiveLabelColor = assistiveLabelColor;
	[self setNeedsLayout];
	}

	- (UIColor *)trailingAssistiveLabelColorForState:(MDCTextControlState)state {
	MDCTextControlColorViewModel *colorViewModel = [self textControlColorViewModelForState:state];
	return colorViewModel.trailingAssistiveLabelColor;
	}

	#pragma mark User Actions

	- (void)handleTap:(UITapGestureRecognizer *)tap {
	if (tap.state == UIGestureRecognizerStateEnded) {
	if (!self.textView.isFirstResponder) {
	[self.textView becomeFirstResponder];
	}
	}
	}

	- (void)textViewChanged:(NSNotification *)notification {
	if (notification.object == self.baseTextAreaTextView) {
	[self setNeedsLayout];
	}
	}

	#pragma mark Notifications

	- (void)observeTextViewNotifications {
	[[NSNotificationCenter defaultCenter] addObserver:self
	selector:@selector(textViewChanged:)
	name:UITextViewTextDidChangeNotification
	object:nil];
	}

	@end