UiCollectionViewCell random images flipping - ios

Question

I have been looking around here for a answer with no success so now ill make a try my self.
Im trying to make a UicollectionView with different cells containing images + an animation with the cells.
I want the cells to do "random flipping" with my images (5 different images)
UIViewAnimationOptionTransitionFlipFromLeft
in a loop with 5-6 sec delay.
the animation i have for the moment is this:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
[cell.superview bringSubviewToFront:collectionView];
[UIView transitionWithView:cell
duration:1.0
options:UIViewAnimationOptionTransitionFlipFromLeft
animations:^{
[UICollectionViewCell commitAnimations];
cell.transform = CGAffineTransformMakeRotation(0.0);
}
completion:^(BOOL finished) {}];
}
I know that i shouldn't use the didSelectItemAtIndexPath, but i used it just to see if the animation were right.
If you check at this video u can see what i mean, on the windows 8 phone. Youtube video

Answer 1

Ok, I was interested on this idea so I prototyped some code. I needs to be specifically tailored to your needs but it can be a good start. Firstly, you will need to subclass your UICollectionViewCell in order to connect an IBOutlet to your imageView inside the cell. Then you can reference my code snippet to get you started.
- (void)viewDidLoad
{
[super viewDidLoad];
self.imageList = #[#"img1.png", #"img2.png", #"img3.png", #"img4.png"];
}
// This assumes your images are inside your Bundle.
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[NSTimer scheduledTimerWithTimeInterval:4.0
target:self
selector:#selector(updateCells:)
userInfo:nil
repeats:YES];
}
- (void)updateCells:(NSTimer *)timer
{
NSArray *visibleIndexPaths = [self.collectionView indexPathsForVisibleItems];
for (NSIndexPath *indexPath in visibleIndexPaths) {
SubclassCollectionViewCell *cell = (SubclassCollectionViewCell *)[self.collectionView cellForItemAtIndexPath:indexPath];
[UIView transitionWithView:cell
duration:1.0f
options:UIViewAnimationOptionTransitionFlipFromLeft
animations:^{
cell.imageView.image = [self randomImage];
} completion:nil];
}
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return 1;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
return cell;
}
- (UIImage *)randomImage
{
NSInteger randomNumber = arc4random() % [self.imageList count];
return [UIImage imageNamed:[self.imageList objectAtIndex:randomNumber]];
}
Update:
If you want only one cell at a time to randomly flip, you will need to take out the for loop in the updateCells method. Instead, try this:
- (void)updateCells:(NSTimer *)timer
{
NSArray *visibleIndexPaths = [self.collectionView indexPathsForVisibleItems];
NSInteger randomIndex = arc4random() % [visibleIndexPaths count];
NSindexPath *randomIndexPath = [NSIndexPath indexPathForItem:randomIndex inSection:0];
SubclassCollectionViewCell *cell = (SubclassCollectionViewCell *)[self.collectionView cellForItemAtIndexPath:indexPath];
[UIView transitionWithView:cell
duration:1.0f
options:UIViewAnimationOptionTransitionFlipFromLeft
animations:^{
cell.imageView.image = [self randomImage];
}
completion:nil
];
}

Answer 2

Edited post:
- (void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
int interval = 5+(rand() % 6);
int section = 0;
int row = (arc4random() % self.cellList.count);
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:section];
CollectionCell *cell = (CollectionCell *)[self.collectionView cellForItemAtIndexPath:indexPath];
[NSTimer scheduledTimerWithTimeInterval:interval
target:self
selector:#selector(updateCells:)
userInfo:cell
repeats:NO];
NSLog(#"seconds: %d", interval);
NSLog(#"row: %d", row);
}
- (void)updateCells:(NSTimer *)timer{
CollectionCell* cell = [timer userInfo];
[UIView transitionWithView:cell
duration:1.0f
options:UIViewAnimationOptionTransitionFlipFromLeft
animations:^{
cell.collectionImageView.image = [self randomImage];
} completion:nil];
int interval = 5+(rand() % 5);
NSLog(#"speed: %d", interval);
int section = 0;
int row = (arc4random() % self.cellList.count);
NSLog(#"row: %d", row);
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:section];
CollectionCell *newCell = (CollectionCell *)[self.collectionView cellForItemAtIndexPath:indexPath];
[NSTimer scheduledTimerWithTimeInterval:interval
target:self
selector:#selector(updateCells:)
userInfo:newCell
repeats:NO];}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return self.cellList.count;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
CGRect frame = self.collectionView.frame;
[collectionView setFrame:frame];
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"ReuseID" forIndexPath:indexPath];
[collectionView setNeedsDisplay];
[self cellTitleAndBackground:cell indexPath:indexPath];
return cell;
}
- (void)cellTitleAndBackground:(CollectionCell *)cell indexPath:(NSIndexPath *)indexPath {
// Get title
NSString *name = [[NSString alloc] initWithFormat:#"%#", self.cellList[indexPath.row]];
// Create title background
UILabel *titleBackground = [[UILabel alloc] initWithFrame:CGRectMake(5, 70, 70, 30)];
titleBackground.backgroundColor = [UIColor blackColor];
titleBackground.alpha = 0.6f;
titleBackground.tag = 70;
[self removeReusedLabel:cell tag:70];
[cell addSubview:titleBackground];
// Create titleLabel
UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(5, 70, 70, 30)];
titleLabel.textColor = [UIColor whiteColor];
titleLabel.font = [UIFont boldSystemFontOfSize:12];
titleLabel.text = name;
titleLabel.backgroundColor = [UIColor clearColor];
titleLabel.textAlignment = NSTextAlignmentCenter;
titleLabel.tag = 72;
[self removeReusedLabel:cell tag:72];
[cell addSubview:titleLabel];
}
-(void)removeReusedLabel:(CollectionCell *)cell tag:(int)tag {
UILabel *foundLabelBackground = (UILabel *)[cell viewWithTag:tag];
if (foundLabelBackground) [foundLabelBackground removeFromSuperview];
}
- (UIImage *)randomImage
{
// Random image for cells
NSInteger randomNumber = arc4random() % [self.imageList count];
return [UIImage imageNamed:[self.imageList objectAtIndex:randomNumber]];
}