本文介绍了添加更多单元格UICollectionView的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
现在我正在从Instagram的图像上移除屏幕的底部，而不是添加新的单元格。如何添加新的单元格而不是替换以前的单元格？
Well right now I am replacing my images from Instagram by getting to the bottom of the screen rather than adding new cells. How would I add new cells rather than replacing previous ones?
这是我的完整的实现文件来检索下一页图像： p>
Here is my total implemantation file to retrieve the next page of images:
@interface StreamViewController () <UITextFieldDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>
@property (nonatomic, strong) NSMutableDictionary *timelineResponse;
@property (nonatomic, strong) CredentialStore *credentialStore;
@property (weak, nonatomic) IBOutlet UICollectionView *collectionView;
@end
@implementation StreamViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self refreshInstagram];
//Refresh
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:@selector(startRefresh:)
forControlEvents:UIControlEventValueChanged];
[self.collectionView addSubview:refreshControl];
//Instigate Navigation Bar Buttons
UIButton *barButton = [UIButton buttonWithType:UIButtonTypeCustom];
[barButton setTitle:@"" forState:UIControlStateNormal];
[barButton setBackgroundImage:[UIImage imageNamed:@"barButton.png"] forState:UIControlStateNormal];
[barButton setBackgroundImage:[UIImage imageNamed:@"barButton_s.png"] forState:UIControlStateHighlighted];
[barButton addTarget:self action:@selector(didTapBarButton:) forControlEvents:UIControlEventTouchUpInside];
barButton.frame = CGRectMake(0.0f, 0.0f, 30.0f, 30.0f);
UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithCustomView:barButton];
self.navBar.leftBarButtonItem = barButtonItem;
UIButton *postButton = [UIButton buttonWithType:UIButtonTypeCustom];
[postButton setTitle:@"" forState:UIControlStateNormal];
[postButton setBackgroundImage:[UIImage imageNamed:@"pen_usIMG.png"] forState:UIControlStateNormal];
[postButton setBackgroundImage:[UIImage imageNamed:@"pen_sIMG.png"] forState:UIControlStateHighlighted];
[postButton addTarget:self action:@selector(didTapPostButton:) forControlEvents:UIControlEventTouchUpInside];
postButton.frame = CGRectMake(0.0f, 0.0f, 30.0f, 30.0f);
UIBarButtonItem *postButtonItem = [[UIBarButtonItem alloc] initWithCustomView:postButton];
self.navBar.rightBarButtonItem = postButtonItem;
//Reload by default
[self.collectionView reloadData];
}
//Global refresh Instagram Method
- (void)refreshInstagram {
[[InstagramClient sharedClient] getPath:@"users/self/feed"
parameters:nil
success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(@"Response: %@", responseObject);
self.timelineResponse = responseObject;
[self.collectionView reloadData];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(@"Failure: %@", error);
}];
}
- (void)nextInstagramPage:(NSIndexPath *)indexPath{
NSDictionary *page = self.timelineResponse[@"pagination"];
NSString *nextPage = page[@"next_url"];
[[InstagramClient sharedClient] getPath:[NSString stringWithFormat:@"%@",nextPage] parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
[self.collectionView cellForItemAtIndexPath:indexPath];
self.timelineResponse = [responseObject mutableCopy];
[self.timelineResponse addEntriesFromDictionary:responseObject];
[self.collectionView reloadData];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(@"Failure: %@", error);
}];
}
- (NSMutableArray *)entries {
return self.timelineResponse[@"data"];
}
- (NSArray *)pages {
return self.timelineResponse[@"pagination"];
}
- (NSURL *)imageUrlForEntryAtIndexPath:(NSIndexPath *)indexPath {
NSDictionary *entry = [self entries][indexPath.row];
NSString *imageUrlString = entry[@"images"][@"standard_resolution"][@"url"];
return [NSURL URLWithString:imageUrlString];
}
#pragma mark - UICollectionViewDelegate
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
//int y = arc4random() % 200+50;
return CGSizeMake(150, 150);
}
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
RNBlurModalView *modal = [[RNBlurModalView alloc] initWithViewController:self title:@"Item Tapped!" message:@"Thank God its working"];
[modal show];
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y == roundf(scrollView.contentSize.height-scrollView.frame.size.height)) {
NSLog(@"we are at the endddd");
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.collectionView performBatchUpdates:^{
[self nextInstagramPage:indexPath];
} completion:^(BOOL finished) {
}
];
}
}
#pragma mark - UICollectionViewDataSource
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return [[self entries] count];
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
if ( indexPath.item == ([[self entries] count] - 1) ) {
// download more data and add it to the 'entries' array
[self refreshInstagram];
}
ImageCell *cell = (ImageCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"imageCell"
forIndexPath:indexPath];
NSURL *url = [self imageUrlForEntryAtIndexPath:indexPath];
NSLog(@"%@", url);
[cell.imageView setImageWithURL:url];
cell.backgroundColor = [UIColor whiteColor];
return cell;
}
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 1;
}
#pragma mark - NavigationBarButtons
- (void)didTapBarButton:(id)sender {
[self.sidePanelController showLeftPanelAnimated:YES];
}
- (void)startRefresh:(UIRefreshControl *)sender {
[self refreshInstagram];
[sender endRefreshing];
}
-(void)didTapPostButton:(id)sender {
}
@end
以下是添加新单元格的方法：
-(void)addNewCells {
[self.collectionView performBatchUpdates:^{
int resultsSize = [[self entries]count];
[self.results addObjectsFromArray:newData];
NSMutableArray *arrayWithIndexPaths = [NSMutableArray array];
for (int i = resultsSize; i < resultsSize + newData.count; i++)
[arrayWithIndexPaths addObject:[NSIndexPath indexPathForRow:i inSection:0]];
}
[self.collectionView insertItemsAtIndexPaths:arrayWithIndexPaths];
}
completion:nil];
}
推荐答案
你必须保留从服务返回的照片的数组。正如Mundi的回答所表明的那样，字典将不起作用，因为添加字典的响应将会替换现有的键/值对。这就是为什么你看到闪烁。
You'll have to keep an array of the photos that are returned from the service. The dictionary won't work, as Mundi's answer suggests, because adding the responses from the dictionary is going to replace existing key/value pairs. That's why you're seeing the flashing.
将 NSMutableArray 属性添加到视图控制器，并从数据中添加条目。
Add an NSMutableArray property to your view controller and add entries from the data to it.
[self.photosArray addObjectsFromArray:responseObject[@"data"]];
然后用户 self.photosArray 条目方法。
这篇关于添加更多单元格UICollectionView的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！