material-components_material-components-ios/components/List/examples/CollectionListCellExampleTypicalUse.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 "MaterialIcons+ic_info.h"
#import "MaterialTypographyScheme.h"
#import "supplemental/CollectionListCellExampleTypicalUse.h"
#import "supplemental/CollectionViewListCell.h"

static NSString *const kReusableIdentifierItem = @"itemCellIdentifier";
static NSString *const kExampleDetailText =
    @"Pellentesque non quam ornare, porta urna sed, malesuada felis. Praesent at gravida felis, "
     "non facilisis enim. Proin dapibus laoreet lorem, in viverra leo dapibus a.";
static const CGFloat kSmallestCellHeight = 40.f;
static const CGFloat kSmallArbitraryCellWidth = 100.f;

@implementation CollectionListCellExampleTypicalUse {
  NSMutableArray *_content;
}

@synthesize collectionViewLayout = _collectionViewLayout;

- (instancetype)init {
  UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
  flowLayout.minimumInteritemSpacing = 0;
  flowLayout.minimumLineSpacing = 1;
  flowLayout.scrollDirection = UICollectionViewScrollDirectionVertical;
  flowLayout.estimatedItemSize = CGSizeMake(kSmallArbitraryCellWidth, kSmallestCellHeight);
  return [self initWithCollectionViewLayout:flowLayout];
}

- (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout {
  self = [super initWithCollectionViewLayout:layout];
  if (self) {
    _collectionViewLayout = layout;
    _typographyScheme = [[MDCTypographyScheme alloc] init];
  }
  return self;
}

- (void)viewDidLoad {
  [super viewDidLoad];

  [self.collectionView setCollectionViewLayout:self.collectionViewLayout];
  self.collectionView.backgroundColor = UIColor.whiteColor;
  self.collectionView.alwaysBounceVertical = YES;
  self.automaticallyAdjustsScrollViewInsets = NO;
  self.parentViewController.automaticallyAdjustsScrollViewInsets = NO;
  if (@available(iOS 11.0, *)) {
    self.collectionView.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentAlways;
  }
  // Register cell class.
  [self.collectionView registerClass:[CollectionViewListCell class]
          forCellWithReuseIdentifier:kReusableIdentifierItem];

  // Populate content with array of text, details text, and number of lines.
  _content = [NSMutableArray array];
  NSDictionary *alignmentValues = @{
    @"Left" : @(NSTextAlignmentLeft),
    @"Right" : @(NSTextAlignmentRight),
    @"Center" : @(NSTextAlignmentCenter),
    @"Just." : @(NSTextAlignmentJustified),
    @"Natural" : @(NSTextAlignmentNatural)
  };

  for (NSString *alignmentKey in alignmentValues) {
    [_content addObject:@[
      [NSString stringWithFormat:@"(%@) Single line text", alignmentKey],
      alignmentValues[alignmentKey],
      @"",
      alignmentValues[alignmentKey]
    ]];
    [_content addObject:@[
      @"",
      alignmentValues[alignmentKey],
      [NSString stringWithFormat:@"(%@) Single line detail text", alignmentKey],
      alignmentValues[alignmentKey]
    ]];
    [_content addObject:@[
      [NSString stringWithFormat:@"(%@) Two line text", alignmentKey],
      alignmentValues[alignmentKey],
      [NSString stringWithFormat:@"(%@) Here is the detail text", alignmentKey],
      alignmentValues[alignmentKey]
    ]];
    [_content addObject:@[
      [NSString stringWithFormat:@"(%@) Two line text (truncated)", alignmentKey],
      alignmentValues[alignmentKey],
      [NSString stringWithFormat:@"(%@) %@", alignmentKey, kExampleDetailText],
      alignmentValues[alignmentKey]
    ]];
    [_content addObject:@[
      [NSString stringWithFormat:@"(%@) Three line text (wrapped)", alignmentKey],
      alignmentValues[alignmentKey],
      [NSString stringWithFormat:@"(%@) %@", alignmentKey, kExampleDetailText],
      alignmentValues[alignmentKey]
    ]];
  }

  [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(contentSizeCategoryDidChange:)
                                               name:UIContentSizeCategoryDidChangeNotification
                                             object:nil];
}

// Handles UIContentSizeCategoryDidChangeNotifications
- (void)contentSizeCategoryDidChange:(__unused NSNotification *)notification {
  [self.collectionView reloadData];
}

#pragma mark - <UICollectionViewDataSource>

- (NSInteger)collectionView:(UICollectionView *)collectionView
     numberOfItemsInSection:(NSInteger)section {
  return [_content count];
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
                  cellForItemAtIndexPath:(NSIndexPath *)indexPath {
  CollectionViewListCell *cell =
      [collectionView dequeueReusableCellWithReuseIdentifier:kReusableIdentifierItem
                                                forIndexPath:indexPath];
  [cell applyTypographyScheme:_typographyScheme];
  cell.mdc_adjustsFontForContentSizeCategory = YES;
  CGFloat cellWidth = CGRectGetWidth(collectionView.bounds);
  if (@available(iOS 11.0, *)) {
    cellWidth -=
        (collectionView.adjustedContentInset.left + collectionView.adjustedContentInset.right);
  }
  [cell setCellWidth:cellWidth];
  cell.titleLabel.text = _content[indexPath.item][0];
  cell.titleLabel.textAlignment = [_content[indexPath.item][1] integerValue];
  cell.detailsTextLabel.text = _content[indexPath.item][2];
  cell.detailsTextLabel.textAlignment = [_content[indexPath.item][3] integerValue];
  if (indexPath.item % 3 == 0) {
    [cell setImage:[MDCIcons imageFor_ic_info]];
  }
  return cell;
}

- (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection {
  [super traitCollectionDidChange:previousTraitCollection];
  [self.collectionView.collectionViewLayout invalidateLayout];
  [self.collectionView reloadData];
}

- (void)viewWillTransitionToSize:(CGSize)size
       withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
  [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];

  [self.collectionView.collectionViewLayout invalidateLayout];

  [coordinator animateAlongsideTransition:nil completion:^(__unused id context) {
    [self.collectionView.collectionViewLayout invalidateLayout];
  }];
}

#pragma mark - CatalogByConvention

+ (NSDictionary *)catalogMetadata {
  return @{
    @"breadcrumbs": @[ @"Lists", @"List Cell Example" ],
    @"description": @"Material Collection Lists are continuous, vertical indexes of text "
    @"or images.",
    @"primaryDemo": @NO,
    @"presentable": @YES,
  };
}

@end