components/Chips/examples/ChipsChoiceExampleViewController.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 "ChipsExamplesSupplemental.h"

#import "MaterialChips.h"
#import "MaterialChips+ChipThemer.h"

@implementation ChipsChoiceExampleViewController {
  MDCChipView *_sizingChip;
  BOOL _isOutlined;
}

- (id)init {
  self = [super init];
  if (self) {
    self.colorScheme = [[MDCSemanticColorScheme alloc] init];
  }
  return self;
}

- (void)loadView {
  [super loadView];
  self.view.backgroundColor = [UIColor whiteColor];

  // This is used to calculate the size of each chip based on the chip setup
  _sizingChip = [[MDCChipView alloc] init];

  // Our preferred CollectionView Layout For chips
  MDCChipCollectionViewFlowLayout *layout = [[MDCChipCollectionViewFlowLayout alloc] init];
  layout.minimumInteritemSpacing = 10;

  _collectionView = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:layout];

  // Since there is no scrolling turning off the delaysContentTouches makes the cells respond faster
  _collectionView.delaysContentTouches = NO;

  // Collection view setup
  _collectionView.dataSource = self;
  _collectionView.delegate = self;
  _collectionView.backgroundColor = [UIColor whiteColor];
  _collectionView.contentInset = UIEdgeInsetsMake(20, 20, 20, 20);
  [_collectionView registerClass:[MDCChipCollectionViewCell class]
      forCellWithReuseIdentifier:@"Cell"];

  [self.view addSubview:_collectionView];
}

- (void)viewDidLoad {
  [super viewDidLoad];

  _isOutlined = NO;
  self.navigationItem.rightBarButtonItem =
      [[UIBarButtonItem alloc] initWithTitle:@"Outlined Style"
                                       style:UIBarButtonItemStylePlain
                                      target:self
                                      action:@selector(switchStyle)];
}


- (void)switchStyle {
  _isOutlined = !_isOutlined;
  NSString *buttonTitle = _isOutlined ? @"Filled Style" : @"Outlined Style";
  [self.navigationItem.rightBarButtonItem setTitle:buttonTitle];
  NSArray *indexPaths = [_collectionView indexPathsForSelectedItems];
  [_collectionView reloadData];
  for (NSIndexPath *path in indexPaths) {
    [_collectionView selectItemAtIndexPath:path
                                  animated:NO
                            scrollPosition:UICollectionViewScrollPositionNone];
  }
}

- (void)viewWillLayoutSubviews {
  [super viewWillLayoutSubviews];

  _collectionView.frame = self.view.bounds;
}


- (NSInteger)collectionView:(UICollectionView *)collectionView
     numberOfItemsInSection:(NSInteger)section {
  return self.titles.count;
}

- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
                           cellForItemAtIndexPath:(NSIndexPath *)indexPath {
  MDCChipCollectionViewCell *cell =
      [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
  MDCChipView *chipView = cell.chipView;

  // Customize Chip
  chipView.titleLabel.text = self.titles[indexPath.row];
  if (indexPath.row == 2) {
    [chipView setEnabled:NO];
  }
  
  MDCChipViewScheme *scheme = [[MDCChipViewScheme alloc] init];
  scheme.colorScheme = self.colorScheme;
  
  if (_isOutlined) {
    [MDCChipViewThemer applyOutlinedVariantWithScheme:scheme toChipView:chipView];
  } else {
    [MDCChipViewThemer applyScheme:scheme toChipView:chipView];
  }

  return cell;
}

- (CGSize)collectionView:(UICollectionView *)collectionView
                  layout:(UICollectionViewLayout*)collectionViewLayout
  sizeForItemAtIndexPath:(NSIndexPath *)indexPath {

  // The size of the chip depends on title here.
  _sizingChip.titleLabel.text = self.titles[indexPath.row];
  return [_sizingChip sizeThatFits:collectionView.bounds.size];
}

- (NSArray *)titles {
  if (!_titles) {
    _titles = @[
      @"The Bronx",
      @"Brooklyn",
      @"Manhattan",
      @"Queens",
      @"Staten Island",
    ];
  }
  return _titles;
}

@end