Faster UICollectionView cells
There are a lot of answers out there for loading images into UITableViews or UICollectionViews. But what if my UICollectionView is displaying views from other view controllers?
Say in my UICollectionViewCell subclass I have this:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.catViewController = [[CatViewController alloc] initWithNibName:nil bundle:nil];
self.catViewController.view.frame = self.bounds;
[self addSubview:self.catViewController.view];
}
return self;
}
And in my collection view Datasource:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
MyCell* cell = [collectionView dequeueReusableCellWithReuseIdentifier:kSomeId forIndexPath:indexPath];
cell.catViewController.data = self.data[indexPath.row]; //see below
return cell;
}
The catViewController has a setter for the data property. When this property is set, the cat will load it's image, along with some other related images for that view. So how do I properly reuse the MyCell cells so that the collection view doesn't stutter each time it creates (or reuses) a cell? Each MyCell takes up the full width of the collection view, which scrolls horizontally, so every time a new cell scrolls into view, the collection view stalls for a moment.
For High performance CollectionView cells , Use following new stuffs in iOS10 with xcode8
Implement protocol "UICollectionViewDataSourcePrefetching" in you ViewController as
class ViewController: UIViewController , UICollectionViewDataSourcePrefetching {
Set following delegates to your collection view in storyboard (see the attached image) or programmatically
In ViewController's viewDidLoad method
collectionView.delegate = self
collectionView.dataSource = self
collectionView.prefetchDataSource = self 