components/ActionSheet/src/private/MDCActionSheetHeaderView.m

// 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 "MDCActionSheetHeaderView.h"

#import <MaterialComponents/MaterialMath.h>
#import <MaterialComponents/MaterialTypography.h>

static const CGFloat kTitleLabelAlpha = (CGFloat)0.87;
static const CGFloat kMessageLabelAlpha = (CGFloat)0.6;
static const CGFloat kMessageOnlyPadding = 23;
static const CGFloat kLeadingPadding = 0;
static const CGFloat kTopStandardPadding = 16;
static const CGFloat kTrailingPadding = 0;
static const CGFloat kTitleOnlyPadding = 18;
static const CGFloat kMiddlePadding = 8;
/** The minimum height a header can be. */
static const CGFloat kMinimumHeaderHeight = 8;

@interface MDCActionSheetHeaderView ()
@property(nonatomic, strong) UILabel *titleLabel;
@property(nonatomic, strong) UILabel *messageLabel;
@end

@implementation MDCActionSheetHeaderView

@synthesize adjustsFontForContentSizeCategory = _adjustsFontForContentSizeCategory;

- (instancetype)initWithFrame:(CGRect)frame {
  self = [super initWithFrame:frame];
  if (self) {
    self.preservesSuperviewLayoutMargins = YES;
    _titleLabel = [[UILabel alloc] initWithFrame:CGRectZero];
    _messageLabel = [[UILabel alloc] initWithFrame:CGRectZero];
    [self addSubview:_titleLabel];
    _titleLabel.font = [UIFont mdc_standardFontForMaterialTextStyle:MDCFontTextStyleSubheadline];
    _titleLabel.numberOfLines = 0;
    _titleLabel.lineBreakMode = NSLineBreakByTruncatingMiddle;
    _titleLabel.accessibilityTraits |= UIAccessibilityTraitHeader;

    [self addSubview:_messageLabel];
    _messageLabel.font = [UIFont mdc_standardFontForMaterialTextStyle:MDCFontTextStyleBody1];
    _messageLabel.numberOfLines = 2;
    _messageLabel.lineBreakMode = NSLineBreakByWordWrapping;
    _messageLabel.textColor = [UIColor.blackColor colorWithAlphaComponent:kMessageLabelAlpha];
  }
  return self;
}

- (void)layoutSubviews {
  [super layoutSubviews];

  CGSize size = CGRectInfinite.size;
  size.width = CGRectGetWidth(self.bounds);
  CGRect labelFrame = [self frameWithLayoutMargins:self.bounds];
  labelFrame = CGRectStandardize(labelFrame);
  labelFrame.size.width = labelFrame.size.width - kLeadingPadding - kTrailingPadding;
  CGSize titleSize = [self.titleLabel sizeThatFits:labelFrame.size];
  CGSize messageSize = [self.messageLabel sizeThatFits:labelFrame.size];
  CGRect titleFrame = CGRectMake(kLeadingPadding + labelFrame.origin.x, kTopStandardPadding,
                                 labelFrame.size.width, titleSize.height);
  CGRect messageFrame =
      CGRectMake(kLeadingPadding + labelFrame.origin.x, CGRectGetMaxY(titleFrame) + kMiddlePadding,
                 labelFrame.size.width, messageSize.height);
  self.titleLabel.frame = titleFrame;
  self.messageLabel.frame = messageFrame;
}

- (CGSize)sizeThatFits:(CGSize)size {
  size.width = size.width - kLeadingPadding - kTrailingPadding;
  CGSize titleSize = [self.titleLabel sizeThatFits:size];
  CGSize messageSize = [self.messageLabel sizeThatFits:size];
  CGFloat contentHeight;
  BOOL messageExist = (self.message) && (![self.message isEqualToString:@""]);
  BOOL titleExist = (self.title) && (![self.title isEqualToString:@""]);
  if (titleExist && messageExist) {
    contentHeight =
        titleSize.height + messageSize.height + (kTopStandardPadding * 2) + kMiddlePadding;
  } else if (messageExist) {
    contentHeight = messageSize.height + (kMessageOnlyPadding * 2);
  } else if (titleExist) {
    contentHeight = titleSize.height + (kTitleOnlyPadding * 2);
  } else {
    contentHeight = kMinimumHeaderHeight;
  }
  CGSize contentSize;
  contentSize.width = ceil(size.width);
  contentSize.height = ceil(contentHeight);
  return contentSize;
}

- (CGRect)frameWithLayoutMargins:(CGRect)frame {
  return UIEdgeInsetsInsetRect(frame, self.layoutMargins);
}

- (void)setTitle:(NSString *)title {
  self.titleLabel.text = title;
  [self setNeedsLayout];
}

- (NSString *)title {
  return self.titleLabel.text;
}

- (void)setMessage:(NSString *)message {
  self.messageLabel.text = message;
  [self updateLabelColors];
  [self setNeedsLayout];
}

- (NSString *)message {
  return self.messageLabel.text;
}

- (void)setTitleFont:(UIFont *)titleFont {
  self.titleLabel.font = titleFont;
  [self updateTitleFont];
}

- (UIFont *)titleFont {
  return self.titleLabel.font;
}

- (void)setMessageFont:(UIFont *)messageFont {
  self.messageLabel.font = messageFont;
  [self updateMessageFont];
}

- (UIFont *)messageFont {
  return self.messageLabel.font;
}

- (void)updateFonts {
  [self updateTitleFont];
  [self updateMessageFont];
}

- (void)updateTitleFont {
  UIFont *titleFont =
      self.titleFont ?: [UIFont mdc_standardFontForMaterialTextStyle:MDCFontTextStyleSubheadline];
  self.titleLabel.font = titleFont;
  [self setNeedsLayout];
}

- (void)updateMessageFont {
  UIFont *messageFont =
      self.messageFont ?: [UIFont mdc_standardFontForMaterialTextStyle:MDCFontTextStyleBody1];
  self.messageLabel.font = messageFont;

  [self setNeedsLayout];
}

- (void)setAdjustsFontForContentSizeCategory:(BOOL)adjustsFontForContentSizeCategory {
  _adjustsFontForContentSizeCategory = adjustsFontForContentSizeCategory;
  self.titleLabel.adjustsFontForContentSizeCategory = adjustsFontForContentSizeCategory;
  self.messageLabel.adjustsFontForContentSizeCategory = adjustsFontForContentSizeCategory;
}

- (UIColor *)defaultTitleTextColor {
  // If message is empty or nil then the title label's alpha value should be lighter, if there is
  // both then the title label's alpha should be darker.
  if (self.message && ![self.message isEqualToString:@""]) {
    return [UIColor.blackColor colorWithAlphaComponent:kTitleLabelAlpha];
  } else {
    return [UIColor.blackColor colorWithAlphaComponent:kMessageLabelAlpha];
  }
}

- (void)updateLabelColors {
  self.titleLabel.textColor = self.titleTextColor ?: [self defaultTitleTextColor];
  self.messageLabel.textColor =
      self.messageTextColor ?: [UIColor.blackColor colorWithAlphaComponent:kMessageLabelAlpha];
}

- (void)setTitleTextColor:(UIColor *)titleTextColor {
  _titleTextColor = titleTextColor;
  [self updateLabelColors];
}

- (void)setMessageTextColor:(UIColor *)messageTextColor {
  _messageTextColor = messageTextColor;
  [self updateLabelColors];
}

@end