dequeueReusableCellWithReuseIdentifier doesn't go through init nor initWithCoder functions - ios

Question

When creating cells for UICollectionView, dequeueReusableCellWithReuseIdentifier doesn't go through init nor initWithCoder function of CategoryView.
The view is creating, it has a proper type (CategoryView) but init nor initWithCoder of CategoryView is not called, so essential functionality is not executed. Is there some other init in this senario?
- (CategoryView *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath {
CategoryView *cell = [cv dequeueReusableCellWithReuseIdentifier:#"CategoryView" forIndexPath:indexPath];
[cell someConfiguration];
return cell;
}

Answer 1

In this case, the problem was that the base class was not specified for your cell prototype in Interface Builder. So make sure the base class is set:
Then, when you call dequeueReusableCellWithReuseIdentifier, using the storyboard identifier you specified in the prototype cell, it calls initWithCoder when the cell is first instantiated. If the cell scrolls out of view and is later re-used for another NSIndexPath, the prepareForReuse is called:
#interface CategoryView : UICollectionViewCell
#end
#implementation CategoryView
- (instancetype)initWithCoder:(NSCoder *)coder {
self = [super initWithCoder:coder];
if (self) {
NSLog(#"init");
}
return self;
}
- (void)prepareForReuse {
[super prepareForReuse];
NSLog(#"reuse");
}
#end

Answer 2

try - (instancetype)initWithFrame:(CGRect)frame
It works for me. I wrote UI programmatically.
Good luck!

Answer 3

UICollectionViews and UITableViews reuse cells to improve performance. initWithCoder: will only run once per reusable cell. As such, if you need something called every time a cell is displayed I would recommend writing a method as follows in your cellForRowAtIndexPath: method:
- (CategoryView *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath {
CategoryView *cell = [cv dequeueReusableCellWithReuseIdentifier:#"CategoryView" forIndexPath:indexPath];
// self.parameters = an NSDictionary of the colors, text, etc. you need to the cell to know about
[cell configureWithParameters:self.parameters];
return cell;
}
Then, inside your configureWithParameters: method you can include colors, text, etc. that will help you setup your CategoryView.
You'll have to declare your configureWithParameters: method in your CateogryView.h as follows:
// CategoryView.h
- (void)configureCell:(NSDictionary *)parameters;
Then include your customizations in the .m as follows:
// CategoryView.m
- (void)configureCell:(NSDictionary *)parameters{
// Put Whatever initialization code you need here
// Example:
self.label.textColor = parameters["color"];
self.label.text = parameters["text"];
}

Answer 4

Make sure you have collection view delegate/datasource connected to your class.
Make sure you give base class for cell.
Make sure your cell has reuse identifier.
Make sure to register Nib for your reuse identifier. (You don't need to do that if your cell present in your collection view in storyboard).
And finally try changing
- (CategoryView *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath {
to
- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath {
Now your
- (instancetype)initWithCoder:(NSCoder *)aDecoder
Should be called.

Answer 5

Assuming you've subclassed UICollectionViewCell, you can put your initialization code in awakeFromNib().