components/List/src/MDCBaseCell.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 "MDCBaseCell.h"

#import "MaterialInk.h"
#import "MaterialShadowLayer.h"

static NSString *const MDCListBaseCellInkViewKey = @"MDCListBaseCellInkViewKey";
static NSString *const MDCListBaseCellCurrentInkColorKey = @"MDCListBaseCellCurrentInkColorKey";
static NSString *const MDCListBaseCellCurrentElevationKey = @"MDCListBaseCellCurrentElevationKey";

@interface MDCBaseCell ()

@property (nonatomic, assign) CGPoint lastTouch;
@property (strong, nonatomic, nonnull) MDCInkView *inkView;

@end

@implementation MDCBaseCell

#pragma mark Object Lifecycle

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

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
  self = [super initWithCoder:aDecoder];
  if (self) {
    MDCInkView *decodedInkView = [aDecoder decodeObjectOfClass:[MDCInkView class]
                                                        forKey:MDCListBaseCellInkViewKey];
    if (decodedInkView) {
      self.inkView = decodedInkView;
    }
    UIColor *decodedColor = [aDecoder decodeObjectOfClass:[UIColor class]
                                                   forKey:MDCListBaseCellCurrentInkColorKey];
    if (decodedColor) {
      self.inkView.inkColor = decodedColor;
    }
    NSNumber *decodedElevation = [aDecoder decodeObjectOfClass:[NSNumber class]
                                                        forKey:MDCListBaseCellCurrentElevationKey];
    if (decodedElevation) {
      self.elevation = (CGFloat)[decodedElevation doubleValue];
    }
    [self commonMDCBaseCellInit];
  }
  return self;
}

- (void)encodeWithCoder:(NSCoder *)coder {
  [super encodeWithCoder:coder];
  [coder encodeObject:_inkView forKey:MDCListBaseCellInkViewKey];
  [coder encodeObject:_inkView.inkColor forKey:MDCListBaseCellCurrentInkColorKey];
  [coder encodeObject:[NSNumber numberWithDouble:(double)_elevation]
               forKey:MDCListBaseCellCurrentInkColorKey];
}

#pragma mark Setup

- (void)commonMDCBaseCellInit {
  if (!self.inkView) {
    self.inkView = [[MDCInkView alloc] initWithFrame:self.bounds];
  }
  _inkView.usesLegacyInkRipple = NO;
  [self addSubview:_inkView];
}

#pragma mark Ink

- (void)startInk {
  [self.inkView startTouchBeganAtPoint:_lastTouch
                              animated:YES
                        withCompletion:nil];
}

- (void)endInk {
  [self.inkView startTouchEndAtPoint:_lastTouch
                            animated:YES
                      withCompletion:nil];
}

#pragma mark Shadow

- (UIBezierPath *)boundingPath {
  return [UIBezierPath bezierPathWithRoundedRect:self.bounds cornerRadius:self.layer.cornerRadius];
}

- (void)updateShadowElevation {
  self.layer.shadowPath = [self boundingPath].CGPath;
  [self.shadowLayer setElevation:self.elevation];
}

#pragma mark - UIResponder

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  [super touchesBegan:touches withEvent:event];
  UITouch *touch = [touches anyObject];
  CGPoint location = [touch locationInView:self];
  self.lastTouch = location;
  [self startInk];
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  [super touchesEnded:touches withEvent:event];
  [self endInk];
}

#pragma mark UIView Overrides

+ (Class)layerClass {
  return [MDCShadowLayer class];
}

- (void)layoutSubviews {
  [super layoutSubviews];
  [self updateShadowElevation];
  self.inkView.frame = self.bounds;
}

#pragma mark UICollectionViewCell Overrides

- (void)setHighlighted:(BOOL)highlighted {
  [super setHighlighted:highlighted];
  if (!highlighted) {
    [self endInk];
  }
}

- (void)prepareForReuse {
  [super prepareForReuse];
  self.elevation = 0;
  [self.inkView cancelAllAnimationsAnimated:NO];
}

#pragma mark Accessors

- (void)setElevation:(MDCShadowElevation)elevation {
  if (elevation == _elevation) {
    return;
  }
  _elevation = elevation;
  [self updateShadowElevation];
}

- (void)setInkColor:(UIColor *)inkColor {
  if ([self.inkColor isEqual:inkColor]) {
    return;
  }
  self.inkView.inkColor = inkColor;
}

- (UIColor *)inkColor {
  return self.inkView.inkColor;
}

- (MDCShadowLayer *)shadowLayer {
  if ([self.layer isMemberOfClass:[MDCShadowLayer class]]) {
    return (MDCShadowLayer *)self.layer;
  }
  return nil;
}

@end