How to load more data in collectionviewcontroller - ios

Question

I had a little problem which is I can't properly reload a new data in collectionview whilst scrolling down at the bottom of collectionviewcontroller. The problem I had starting at this code if (indexPath.row == [selectedVideoData count] - 1). Below is my full code for collectionviewcontroller :
#import "PageVideosCVC.h"
#import "facebook.h"
#import "MBProgressHUD.h"
#import <AFNetworking/AFNetworking.h>
#import <AVFoundation/AVFoundation.h>
#import <SDWebImage/UIImageView+WebCache.h>
#interface PageVideosCVC () <UICollectionViewDataSource,UICollectionViewDelegate>
#end
#implementation PageVideosCVC
#synthesize selectedVideoData, selectNextVideoData;
static NSString * const reuseIdentifier = #"Cell";
-(void) viewWillAppear:(BOOL)animated {
UINavigationBar *navBar = [[UINavigationBar alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 50)];
[UINavigationBar appearance].barTintColor = [UIColor lightGrayColor];
[self.view addSubview: navBar];
UIBarButtonItem *cancelItem = [[UIBarButtonItem alloc] initWithTitle:#"< Back"
style:UIBarButtonItemStylePlain
target:self
action:#selector(backButtonTapped:)];
// UIBarButtonItem *doneItem = [[UIBarButtonItem alloc] initWithTitle:#"Done"
// style:UIBarButtonItemStyleBordered
// target:self action:nil];
NSString *selectedPageName = [[NSString alloc] initWithFormat:#"%#", self.pageName];
UINavigationItem *navItem = [[UINavigationItem alloc] initWithTitle:selectedPageName];
// navItem.rightBarButtonItem = doneItem;
navItem.leftBarButtonItem = cancelItem;
navBar.items = [NSArray arrayWithObjects: navItem,nil];
[UIBarButtonItem appearance].tintColor = [UIColor blueColor];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.automaticallyAdjustsScrollViewInsets = NO;
self.collectionView.delegate = self;
self.collectionView.dataSource = self;
facebook *fb = [[facebook alloc] init];
[MBProgressHUD showHUDAddedTo:self.view animated:YES];
NSDictionary *fbVideoParams = #{ #"fields": #"videos.limit(10){source,description,thumbnails.limit(1),length}"};
[fb fetchVideoInformationFromPages:fbVideoParams videoID:self.videoID completionHandler:^(NSDictionary *videoResult) {
if (videoResult != nil) {
selectedVideoData = [videoResult valueForKeyPath:#"videos.data"];
dispatch_async(dispatch_get_main_queue(), ^{
[self.collectionView reloadData];
[MBProgressHUD hideHUDForView:self.view animated:YES];
});
}
}];
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = NO;
// Register cell classes
// [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:reuseIdentifier];
// Do any additional setup after loading the view.
}
#pragma mark <UICollectionViewDataSource>
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return selectedVideoData.count;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];
// Configure the cell
// This is a last cell, I wanna load next video data from fb.
if (indexPath.row == [selectedVideoData count] - 1) {
NSString *fbToken = [facebook currentFBAccessToken];
NSString *fbNextVideoURL = [NSString stringWithFormat:#"https://graph.facebook.com/v2.5/606246146140197/videos?access_token=%#&pretty=0&fields=source,description,thumbnails.limit(1),length&limit=10&after=ODYxOTA5OTEzOTA3MTUx", fbToken];
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
[MBProgressHUD showHUDAddedTo:self.view animated:YES];
[manager GET:fbNextVideoURL parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
selectNextVideoData = [responseObject valueForKey:#"data"];
NSLog(#"JSON Next Video: %#", selectNextVideoData);
dispatch_async(dispatch_get_main_queue(), ^{
[MBProgressHUD hideHUDForView:self.view animated:YES];
// I had a problem setting the right thumbnail here.
UIImageView *imgView = (UIImageView *)[cell viewWithTag:100];
NSURL *thumbnailImage = [NSURL URLWithString:[selectNextVideoData valueForKeyPath:#"thumbnails.data"]];
// NSLog(#"JSON Next Video: %#", thumbnailImage);
[imgView sd_setImageWithURL:thumbnailImage placeholderImage:[UIImage imageNamed:#"placeholder.jpg"]];
[self.collectionView reloadData];
});
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error: %#", error);
}];
} else {
UIImageView *imgView = (UIImageView *)[cell viewWithTag:100];
NSURL *thumbnailImage = [NSURL URLWithString:[selectedVideoData valueForKeyPath:#"thumbnails.data.uri"][indexPath.row][0]];
[imgView sd_setImageWithURL:thumbnailImage placeholderImage:[UIImage imageNamed:#"placeholder.jpg"]];
}
return cell;
}
#pragma mark <UICollectionViewDelegate>
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
// NSLog(#"videos : %#", selectedVideoData);
// NSLog(#"videos source : %#", [selectedVideoData valueForKeyPath:#"source"][indexPath.row]);
NSURL *videoURL = [NSURL URLWithString:[selectedVideoData valueForKeyPath:#"source"][indexPath.row]];
self.playerController = [[MPMoviePlayerController alloc] initWithContentURL:videoURL];
[[self.playerController view] setFrame:[self.view bounds]]; // Frame must match parent view
[self.view addSubview:[self.playerController view]];
self.playerController.movieSourceType = MPMovieSourceTypeStreaming;
self.playerController.controlStyle = MPMovieControlStyleFullscreen;
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(doneButtonClick:) name:MPMoviePlayerPlaybackDidFinishNotification object:nil];
[self.playerController play];
// Play the video using AVPlayer iOS9 above
// AVPlayer *player = [AVPlayer playerWithURL:videoURL];
// AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:player];
// playerLayer.frame = self.view.bounds;
// [self.view.layer addSublayer:playerLayer];
// [player play];
}
-(void)doneButtonClick:(NSNotification*)aNotification{
NSNumber *reason = [aNotification.userInfo objectForKey:MPMoviePlayerPlaybackDidFinishReasonUserInfoKey];
if ([reason intValue] == MPMovieFinishReasonUserExited) {
// Your done button action here
// [self dismissViewControllerAnimated:YES completion:nil];
NSLog(#"done button tapped");
[[NSNotificationCenter defaultCenter] removeObserver:self
name:MPMoviePlayerDidExitFullscreenNotification
object:nil];
[self.playerController stop];
[self.playerController.view removeFromSuperview];
}
}
- (IBAction)backButtonTapped:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
}
#end

Answer 1

Perhaps rather than this approach you can try scrollView Delegate Methods :
- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
CGPoint offset = aScrollView.contentOffset;
CGRect bounds = aScrollView.bounds;
CGSize size = aScrollView.contentSize;
UIEdgeInsets inset = aScrollView.contentInset;
float y = offset.y + bounds.size.height - inset.bottom;
float h = size.height;
// NSLog(#"offset: %f", offset.y);
// NSLog(#"content.height: %f", size.height);
// NSLog(#"bounds.height: %f", bounds.size.height);
// NSLog(#"inset.top: %f", inset.top);
// NSLog(#"inset.bottom: %f", inset.bottom);
// NSLog(#"pos: %f of %f", y, h);
float reload_distance = 10;
if(y > h + reload_distance) {
NSLog(#"load more rows");
}
}