components/Collections/src/private/MDCCollectionInfoBarView.m

/*
 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 "MDCCollectionInfoBarView.h"

#import "MaterialPalettes.h"
#import "MaterialShadowLayer.h"
#import "MaterialTypography.h"

const CGFloat MDCCollectionInfoBarAnimationDuration = 0.3f;
const CGFloat MDCCollectionInfoBarHeaderHeight = 48.0f;
const CGFloat MDCCollectionInfoBarFooterHeight = 48.0f;

static const CGFloat MDCCollectionInfoBarLabelHorizontalPadding = 16.0f;

static inline UIColor *CollectionInfoBarBlueColor(void) {
  return MDCPalette.bluePalette.accent200;
}

static inline UIColor *CollectionInfoBarRedColor(void) {
  return MDCPalette.redPalette.tint500;
}

@interface ShadowedView : UIView
@end

@implementation ShadowedView
+ (Class)layerClass {
  return [MDCShadowLayer class];
}
@end

@implementation MDCCollectionInfoBarView {
  CGFloat _backgroundTransformY;
  CALayer *_backgroundBorderLayer;
  UITapGestureRecognizer *_tapGesture;
}

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

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

- (void)commonMDCCollectionInfoBarViewInit {
  self.backgroundColor = [UIColor clearColor];
  self.userInteractionEnabled = NO;
  _backgroundView = [[ShadowedView alloc] initWithFrame:self.bounds];
  _backgroundView.autoresizingMask =
      (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
  _backgroundView.hidden = YES;

  _titleLabel = [[UILabel alloc] initWithFrame:CGRectZero];
  _titleLabel.backgroundColor = [UIColor clearColor];
  _titleLabel.textAlignment = NSTextAlignmentCenter;
  _titleLabel.font = [MDCTypography body1Font];
  _titleLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth;
  [_backgroundView addSubview:_titleLabel];

  [self addSubview:_backgroundView];

  _tapGesture =
      [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];
  [_backgroundView addGestureRecognizer:_tapGesture];
}

- (void)layoutSubviews {
  [super layoutSubviews];

  UIEdgeInsets collectionViewSafeAreaInsets = UIEdgeInsetsZero;
#if defined(__IPHONE_11_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_11_0)
    if (@available(iOS 11.0, *)) {
      if (self.superview) {
        collectionViewSafeAreaInsets = self.superview.safeAreaInsets;
      }
    }
#endif
  CGFloat leftInset = MAX(MDCCollectionInfoBarLabelHorizontalPadding,
                          collectionViewSafeAreaInsets.left);
  CGFloat rightInset = MAX(MDCCollectionInfoBarLabelHorizontalPadding,
                           collectionViewSafeAreaInsets.right);
  CGFloat height = [_kind isEqualToString:MDCCollectionInfoBarKindHeader] ?
      MDCCollectionInfoBarHeaderHeight : MDCCollectionInfoBarFooterHeight;
  _titleLabel.frame =
      CGRectMake(leftInset, 0, CGRectGetWidth(self.bounds) - (leftInset + rightInset), height);

  if (_shouldApplyBackgroundViewShadow) {
    [self setShouldApplyBackgroundViewShadow:_shouldApplyBackgroundViewShadow];
  }
}

- (void)layoutSublayersOfLayer:(CALayer *)layer {
  [super layoutSublayersOfLayer:layer];
  // Set border layer frame.
  _backgroundBorderLayer.frame = CGRectMake(-1, 0, CGRectGetWidth(self.backgroundView.bounds) + 2,
                                            CGRectGetHeight(self.backgroundView.bounds) + 1);
}

- (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes {
  [super applyLayoutAttributes:layoutAttributes];
  self.layer.zPosition = layoutAttributes.zIndex;
}

- (void)setTintColor:(UIColor *)tintColor {
  _tintColor = tintColor;
  _backgroundView.backgroundColor = _tintColor;
}

- (void)setMessage:(NSString *)message {
  _message = message;
  _titleLabel.text = message;
}

- (void)setKind:(NSString *)kind {
  _kind = kind;
  _backgroundTransformY = CGRectGetHeight(self.bounds);
  if ([kind isEqualToString:MDCCollectionInfoBarKindHeader]) {
    _backgroundTransformY *= -1.0;
  }
  _backgroundView.transform = CGAffineTransformMakeTranslation(0, _backgroundTransformY);
}

- (void)setShouldApplyBackgroundViewShadow:(BOOL)shouldApplyBackgroundViewShadow {
  _shouldApplyBackgroundViewShadow = shouldApplyBackgroundViewShadow;
  MDCShadowLayer *shadowLayer = (MDCShadowLayer *)_backgroundView.layer;
  shadowLayer.elevation = shouldApplyBackgroundViewShadow ? 1 : 0;
}

- (void)setTextAlignment:(NSTextAlignment)textAlignment {
  _textAlignment = textAlignment;
  _titleLabel.textAlignment = textAlignment;
}

- (void)setStyle:(MDCCollectionInfoBarViewStyle)style {
  _style = style;
  if (style == MDCCollectionInfoBarViewStyleHUD) {
    self.allowsTap = NO;
    self.shouldApplyBackgroundViewShadow = NO;
    self.textAlignment = NSTextAlignmentLeft;
    self.tintColor = CollectionInfoBarBlueColor();
    self.titleLabel.textColor = [UIColor whiteColor];
    self.autoDismissAfterDuration = 1.0f;
    self.backgroundView.alpha = 0.9f;
  } else if (style == MDCCollectionInfoBarViewStyleActionable) {
    self.allowsTap = YES;
    self.shouldApplyBackgroundViewShadow = YES;
    self.textAlignment = NSTextAlignmentCenter;
    self.tintColor = [UIColor whiteColor];
    self.titleLabel.textColor = CollectionInfoBarRedColor();
    self.autoDismissAfterDuration = 0.0f;
    self.backgroundView.alpha = 1.0f;
    self.isAccessibilityElement = YES;
    self.accessibilityTraits = UIAccessibilityTraitButton;
    self.accessibilityLabel = self.message;

    // Adds border to be positioned during sublayer layout.
    self.backgroundView.clipsToBounds = YES;
    if (!_backgroundBorderLayer) {
      _backgroundBorderLayer = [CALayer layer];
      _backgroundBorderLayer.borderColor = [UIColor colorWithWhite:0 alpha:0.1f].CGColor;
      _backgroundBorderLayer.borderWidth = 1.0f / [[UIScreen mainScreen] scale];
      [self.backgroundView.layer addSublayer:_backgroundBorderLayer];
    }
  }
}

- (BOOL)isVisible {
  return !_backgroundView.hidden;
}

- (void)showAnimated:(BOOL)animated {
  [self layoutIfNeeded];
  _backgroundView.hidden = NO;

  // Notify delegate.
  if ([_delegate respondsToSelector:@selector(infoBar:willShowAnimated:willAutoDismiss:)]) {
    [_delegate infoBar:self willShowAnimated:animated willAutoDismiss:[self shouldAutoDismiss]];
  }

  NSTimeInterval duration = (animated) ? MDCCollectionInfoBarAnimationDuration : 0.0f;
  [UIView animateWithDuration:duration
      delay:0
      options:UIViewAnimationOptionCurveEaseOut
      animations:^{
        self.backgroundView.transform = CGAffineTransformIdentity;
      }
      completion:^(__unused BOOL finished) {
        self.userInteractionEnabled = self.allowsTap;

        // Notify delegate.
        if ([self.delegate respondsToSelector:@selector(infoBar:didShowAnimated:willAutoDismiss:)]) {
          [self.delegate infoBar:self
                 didShowAnimated:animated
                 willAutoDismiss:[self shouldAutoDismiss]];
        }

        [self autoDismissIfNecessaryWithAnimation:animated];
      }];
}

- (void)dismissAnimated:(BOOL)animated {
  // Notify delegate.
  if ([_delegate respondsToSelector:@selector(infoBar:willDismissAnimated:willAutoDismiss:)]) {
    [_delegate infoBar:self willDismissAnimated:animated willAutoDismiss:[self shouldAutoDismiss]];
  }

  NSTimeInterval duration = (animated) ? MDCCollectionInfoBarAnimationDuration : 0.0f;
  [UIView animateWithDuration:duration
      delay:0
      options:UIViewAnimationOptionCurveEaseIn
      animations:^{
        self.backgroundView.transform =
            CGAffineTransformMakeTranslation(0, self->_backgroundTransformY);
      }
      completion:^(__unused BOOL finished) {
        self.userInteractionEnabled = NO;
        self.backgroundView.hidden = YES;

        // Notify delegate.
        if ([self.delegate respondsToSelector:@selector(infoBar:didDismissAnimated:didAutoDismiss:)]) {
          [self.delegate infoBar:self
                didDismissAnimated:animated
                    didAutoDismiss:[self shouldAutoDismiss]];
        }
      }];
}

#pragma mark - Private

- (void)handleTapGesture:(__unused UITapGestureRecognizer *)recognizer {
  if ([_delegate respondsToSelector:@selector(didTapInfoBar:)]) {
    [_delegate didTapInfoBar:self];
  }
}

- (BOOL)shouldAutoDismiss {
  return (_autoDismissAfterDuration > 0);
}

- (void)autoDismissIfNecessaryWithAnimation:(BOOL)animation {
  if ([self shouldAutoDismiss]) {
    dispatch_time_t popTime =
        dispatch_time(DISPATCH_TIME_NOW, (int64_t)(_autoDismissAfterDuration * NSEC_PER_SEC));
    dispatch_after(popTime, dispatch_get_main_queue(), ^{
      [self dismissAnimated:animation];
    });
  }
}

@end