Added sample project using networking and infinite scrolling and random cats

examples/CatDealsCollectionView/Sample/ViewController.m

@@ -0,0 +1,244 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import "ViewController.h"
+
+#import <AsyncDisplayKit/AsyncDisplayKit.h>
+#import "ItemNode.h"
+#import "BlurbNode.h"
+#import "LoadingNode.h"
+
+static const NSTimeInterval kWebResponseDelay = 1.0;
+static const BOOL kSimulateWebResponse = YES;
+static const NSInteger kBatchSize = 20;
+
+static const CGFloat kHorizontalSectionPadding = 10.0f;
+static const CGFloat kVerticalSectionPadding = 20.0f;
+
+@interface ViewController () <ASCollectionViewDataSource, ASCollectionViewDelegateFlowLayout>
+{
+  ASCollectionView *_collectionView;
+  NSMutableArray *_data;
+}
+
+@end
+
+
+@implementation ViewController
+
+#pragma mark -
+#pragma mark UIViewController.
+
+- (instancetype)init
+{
+  self = [super init];
+  
+  if (self) {
+    
+    self.title = @"Cat Deals";
+    
+    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
+    
+    _collectionView = [[ASCollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:layout];
+    _collectionView.asyncDataSource = self;
+    _collectionView.asyncDelegate = self;
+    _collectionView.backgroundColor = [UIColor grayColor];
+    _collectionView.leadingScreensForBatching = 2;
+    
+    ASRangeTuningParameters fetchDataTuning;
+    fetchDataTuning.leadingBufferScreenfuls = 2;
+    fetchDataTuning.trailingBufferScreenfuls = 1;
+    [_collectionView setTuningParameters:fetchDataTuning forRangeType:ASLayoutRangeTypeFetchData];
+    
+    ASRangeTuningParameters preRenderTuning;
+    preRenderTuning.leadingBufferScreenfuls = 1;
+    preRenderTuning.trailingBufferScreenfuls = 0.5;
+    [_collectionView setTuningParameters:preRenderTuning forRangeType:ASLayoutRangeTypeDisplay];
+    
+    [_collectionView registerSupplementaryNodeOfKind:UICollectionElementKindSectionHeader];
+    [_collectionView registerSupplementaryNodeOfKind:UICollectionElementKindSectionFooter];
+    
+    _data = [[NSMutableArray alloc] init];
+    
+    self.navigationItem.leftItemsSupplementBackButton = YES;
+    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(reloadTapped)];
+  }
+  
+  return self;
+}
+
+- (void)viewDidLoad
+{
+  [super viewDidLoad];
+  
+  [self.view addSubview:_collectionView];
+  [self fetchMoreCatsWithCompletion:nil];
+}
+
+- (void)fetchMoreCatsWithCompletion:(void (^)(BOOL))completion {
+  if (kSimulateWebResponse) {
+    __weak typeof(self) weakSelf = self;
+    void(^mockWebService)() = ^{
+      NSLog(@"ViewController \"got data from a web service\"");
+      ViewController *strongSelf = weakSelf;
+      if (strongSelf != nil)
+      {
+        NSLog(@"ViewController is not nil");
+        [strongSelf appendMoreItems:kBatchSize completion:completion];
+        NSLog(@"ViewController finished updating collectionView");
+      }
+      else {
+        NSLog(@"ViewController is nil - won't update collectionView");
+      }
+    };
+    
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kWebResponseDelay * NSEC_PER_SEC)), dispatch_get_main_queue(), mockWebService);
+  } else {
+    [self appendMoreItems:kBatchSize completion:completion];
+  }
+}
+
+- (void)appendMoreItems:(NSInteger)numberOfNewItems completion:(void (^)(BOOL))completion {
+  NSArray *newData = [self getMoreData:numberOfNewItems];
+  dispatch_async(dispatch_get_main_queue(), ^{
+    [_collectionView performBatchUpdates:^{
+      [_data addObjectsFromArray:newData];
+      NSArray *addedIndexPaths = [self indexPathsForObjects:newData];
+      [_collectionView insertItemsAtIndexPaths:addedIndexPaths];
+    } completion:completion];
+  });
+}
+
+- (NSArray *)getMoreData:(NSInteger)count {
+  NSMutableArray *data = [NSMutableArray array];
+  for (int i = 0; i < count; i++) {
+    [data addObject:[ItemViewModel randomItem]];
+  }
+  return data;
+}
+
+- (NSArray *)indexPathsForObjects:(NSArray *)data {
+  NSMutableArray *indexPaths = [NSMutableArray array];
+  NSInteger section = 0;
+  for (ItemViewModel *viewModel in data) {
+    NSInteger item = [_data indexOfObject:viewModel];
+    NSAssert(item < [_data count] && item != NSNotFound, @"Item should be in _data");
+    [indexPaths addObject:[NSIndexPath indexPathForItem:item inSection:section]];
+  }
+  return indexPaths;
+}
+
+- (void)viewWillLayoutSubviews
+{
+  _collectionView.frame = self.view.bounds;
+}
+
+
+- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
+  [_collectionView.collectionViewLayout invalidateLayout];
+}
+
+- (BOOL)prefersStatusBarHidden
+{
+  return YES;
+}
+
+- (void)reloadTapped
+{
+  [_collectionView reloadData];
+}
+
+#pragma mark -
+#pragma mark ASCollectionView data source.
+
+- (ASCellNode *)collectionView:(ASCollectionView *)collectionView nodeForItemAtIndexPath:(NSIndexPath *)indexPath
+{
+  ItemViewModel *viewModel = _data[indexPath.item];
+  return [[ItemNode alloc] initWithViewModel:viewModel];
+}
+
+- (ASCellNode *)collectionView:(UICollectionView *)collectionView nodeForSupplementaryElementOfKind:(nonnull NSString *)kind atIndexPath:(nonnull NSIndexPath *)indexPath {
+  if ([kind isEqualToString:UICollectionElementKindSectionHeader] && indexPath.section == 0) {
+    return [[BlurbNode alloc] init];
+  } else if ([kind isEqualToString:UICollectionElementKindSectionFooter] && indexPath.section == 0) {
+    return [[LoadingNode alloc] init];
+  }
+  return nil;
+}
+
+- (CGSize)collectionView:(ASCollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section {
+  if (section == 0) {
+    CGFloat width = CGRectGetWidth(self.view.frame) - 2 * kHorizontalSectionPadding;
+    return CGSizeMake(width, [BlurbNode desiredHeightForWidth:width]);
+  }
+  return CGSizeZero;
+}
+
+- (CGSize)collectionView:(ASCollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section {
+  if (section == 0) {
+    CGFloat width = CGRectGetWidth(self.view.frame);
+    return CGSizeMake(width, [LoadingNode desiredHeightForWidth:width]);
+  }
+  return CGSizeZero;
+}
+
+- (ASSizeRange)collectionView:(ASCollectionView *)collectionView constrainedSizeForNodeAtIndexPath:(NSIndexPath *)indexPath {
+  CGFloat collectionViewWidth = CGRectGetWidth(self.view.frame) - 2 * kHorizontalSectionPadding;
+  CGFloat oneItemWidth = [ItemNode preferredViewSize].width;
+  NSInteger numColumns = floor(collectionViewWidth / oneItemWidth);
+  // Number of columns should be at least 1
+  numColumns = MAX(1, numColumns);
+  
+  CGFloat totalSpaceBetweenColumns = (numColumns - 1) * kHorizontalSectionPadding;
+  CGFloat itemWidth = ((collectionViewWidth - totalSpaceBetweenColumns) / numColumns);
+  CGSize itemSize = [ItemNode sizeForWidth:itemWidth];
+  return ASSizeRangeMake(itemSize, itemSize);
+}
+
+- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
+{
+  return [_data count];
+}
+
+- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
+{
+  return 1;
+}
+
+- (void)collectionViewLockDataSource:(ASCollectionView *)collectionView
+{
+  // lock the data source
+  // The data source should not be change until it is unlocked.
+}
+
+- (void)collectionViewUnlockDataSource:(ASCollectionView *)collectionView
+{
+  // unlock the data source to enable data source updating.
+}
+
+- (void)collectionView:(UICollectionView *)collectionView willBeginBatchFetchWithContext:(ASBatchContext *)context
+{
+  NSLog(@"fetch additional content");
+  [self fetchMoreCatsWithCompletion:^(BOOL finished){
+    [context completeBatchFetching:YES];
+  }];
+}
+
+- (UIEdgeInsets)collectionView:(ASCollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
+  return UIEdgeInsetsMake(kVerticalSectionPadding, kHorizontalSectionPadding, kVerticalSectionPadding, kHorizontalSectionPadding);
+}
+
+-(void)dealloc
+{
+  NSLog(@"ViewController is deallocing");
+}
+
+@end