components/Chips/src/MDCChipCollectionViewCell.m

// Copyright 2017-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 <CoreGraphics/CoreGraphics.h>

#import "MDCChipCollectionViewCell.h"

#import "private/MDCChipView+Private.h"
#import "MDCChipView.h"

@implementation MDCChipCollectionViewCell

- (instancetype)initWithFrame:(CGRect)rect {
  if (self = [super initWithFrame:rect]) {
    _chipView = [self createChipView];
    [self.contentView addSubview:_chipView];
  }
  return self;
}

- (void)setBounds:(CGRect)bounds {
  [super setBounds:bounds];

  // We update selected state here in the event that the MDCChipView will resize upon selection.
  // This way any layout changes on selection can be animated.
  _chipView.selected = self.selected;
}

- (void)layoutSubviews {
  [super layoutSubviews];

  BOOL animated = NO;
  if (self.alwaysAnimateResize) {
    BOOL isFrameNonzero = !CGRectIsEmpty(_chipView.frame) && !CGRectIsEmpty(self.bounds);
    BOOL isFrameDifferent = !CGRectEqualToRect(_chipView.frame, self.bounds);

    animated = isFrameNonzero && isFrameDifferent;
  }

  if (animated) {
    [UIView animateWithDuration:0.25
                     animations:^{
                       self.chipView.frame = self.bounds;
                       [self.chipView layoutIfNeeded];
                     }];
  } else {
    _chipView.frame = self.bounds;
  }
}

- (MDCChipView *)createChipView {
  return [[MDCChipView alloc] init];
}

- (CGSize)sizeThatFits:(CGSize)size {
  return [_chipView sizeThatFits:size];
}

- (CGSize)intrinsicContentSize {
  return [_chipView intrinsicContentSize];
}

- (void)setSelected:(BOOL)selected {
  [super setSelected:selected];

  if (self.alwaysAnimateResize && [_chipView willChangeSizeWithSelectedValue:selected]) {
    // Since MDCChipView can resize when it is selected, if a resize will occur we need to delay our
    // selected state update until our next layout.
    [self setNeedsLayout];
  } else {
    _chipView.selected = selected;
  }
}

- (void)setHighlighted:(BOOL)highlighted {
  [super setHighlighted:highlighted];

  _chipView.highlighted = highlighted;
}

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
  UIView *view = [super hitTest:point withEvent:event];
  if (view == _chipView) {
    // We want the collection view cell to be responsible for managing selected and highlighted
    // states, so we highjack touches that go to the chip view. Touches on the accessory view will
    // still pass through for cases like delete buttons.
    return self;
  }
  return view;
}

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
  CGRect hitAreaRect =
      UIEdgeInsetsInsetRect(CGRectStandardize(self.bounds), _chipView.hitAreaInsets);
  return CGRectContainsPoint(hitAreaRect, point);
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  [super touchesBegan:touches withEvent:event];

  [_chipView startTouchBeganAnimationAtPoint:[self locationFromTouches:touches]];
}

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

  [_chipView startTouchEndedAnimationAtPoint:[self locationFromTouches:touches]];
}

- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  [super touchesCancelled:touches withEvent:event];

  [_chipView startTouchEndedAnimationAtPoint:[self locationFromTouches:touches]];
}

- (CGPoint)locationFromTouches:(NSSet<UITouch *> *)touches {
  UITouch *touch = [touches anyObject];
  return [touch locationInView:_chipView];
}

@end