焦点引擎在集合视图单元上不起作用

Question

Just started playing around with tvOS and I can't get the focus engine to work on my collection view. The focus works with just about every other UI element such as buttons and table views but not the collection view.

I've tried overriding the delegate canFocusItemAtIndexPath and setting the cell to cell.camBecomeFocused() but none of it is working.

Thanks guys

Answer 1

You should take a look at the preferredFocusedView method.

https://developer.apple.com/library/prerelease/tvos/documentation/UIKit/Reference/UIFocusEnvironment_Protocol/index.html#//apple_ref/occ/intfp/UIFocusEnvironment/preferredFocusedView

You can add this to your Collection View Cell in order to specify what subview should get the focus when the cell is focused. For example:

- (UIView *)preferredFocusedView
{
    // In this case, there would be a UITextField hooked up as _myTextField_
    return self.myTextField;
}

Now when the Collection View Cell is focused, in this example, the Text Field will get the focus.

Answer 2

I had same issue that I could not focus the UICollectionView when reload. This solution fixed mine problem. As said as Apple engineer, there is not any focus for the UICollectionViewCells by default but your imageView can be set adjustsImageWhenAncestorFocused to YES makes appearance of the focus in the collectionViewCell.

Here is the code.

cell.imageView.adjustsImageWhenAncestorFocused  = true

Also refer to this link. https://forums.developer.apple.com/message/56262#56262