Unexpected behaviour when adding subviews to UICollectionViewCell - objective-c

Question

I'm currently facing a strange issue with UICollectionViewCell when adding subviews to it but only during certain situations.
Here is the scenario:
I have a "container" view which conforms to a very specific protocol (ADGControl) with a nested view, typically a UIKit control subclass I.e MyCustomTextField : UITextField for custom controls.
The "container" view exposes a property called "innerControlView" which holds a strong reference to the custom control which is what I'm trying to add as a sub view to the cell's content view.
Here is the code:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
FormControlCollectionViewCell *cell = [self.formCollectionView dequeueReusableCellWithReuseIdentifier:#"formControlCell" forIndexPath:indexPath];
NSArray *sectionContents = [_controlList objectAtIndex:[indexPath section]];
// This works
//UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 315.0f, 30.0f)];
//textField.borderStyle = UITextBorderStyleLine;
//[cell.controlView addSubview:textField];
// This doesn't (see the behaviour in video clip)
id <ADGControl> control = [sectionContents objectAtIndex:[indexPath row]]; // The container view I'm referring to
[cell.contentView addSubview:(UIView *)[control innerControlView]]; // [control innerControlView] is the typical UIKit control subclass for custom controls. In this example it will be a UITextField
return cell;
}
As you can see in the code comments above, whenever I try to add just a UIKit control (textField) directly, it works just fine. However, as soon as I try to add my custom control ([control innerControlView] I get the unexpected behaviour as seen in the video clip here: http://media.shinywhitebox.com/ryno-burger/ios-simulator-ios-simulator-ipad-ios-a
The above link is just a short 23 seconds video clip to better demonstrate the "unexpected behaviour" that I get.
If anybody can point out what I'm doing wrong of what the issue might be I will be grateful.
Thanks

Answer 1

As you can read in the documentation on UICollectionViewCells, you shouldn't add content subviews to the cell itself, but to it's contentView.
And, like said before in my comment, you shouldn't add subviews in the data source, but in the subclass. You already noted that initWithFrame: wasn't called, use initWithCoder: instead:
-(id)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self) {
// Add your subviews here
// self.contentView for content
// self.backgroundView for the cell background
// self.selectedBackgroundView for the selected cell background
}
return self;
}

Answer 2

A view can only be in one superview at once. If its already a subview of your container view, you can't just add it as a subview of another view (your cell).
It's not really clear why you're using a view as part of your model object, but you'll either have to change that or remove the inner view from its current superview before adding it to the cell.