禁用焦点触发的UICollectionView滚动

Question

有没有办法禁用自动滚动UICollectionView时单元格聚焦？我想在聚焦时手动调整单元格的内容偏移量.

我不想更新内容偏移量:

- (void)didUpdateFocusInContext:(UIFocusUpdateContext *)context
       withAnimationCoordinator:(UIFocusAnimationCoordinator *)coordinator
{
    [coordinator addCoordinatedAnimations:^
     {
         [UIView animateWithDuration:[UIView inheritedAnimationDuration]
                          animations:^
          {
              // Move next focused cell.
              if ([context.nextFocusedView isKindOfClass:[YBZEventCollectionViewCell class]])
              {
                  UICollectionViewCell *cell = (UICollectionViewCell *)context.nextFocusedView;

                  CGPoint offset = CGPointMake(CGRectGetMinX(cell.frame), 0.0f);

                  [_collectionView setContentOffset:offset];
              }
          }];

     } completion:nil];
}

这是有效的,但由于焦点引擎也移动我的单元格(滚动它)我最终得到的动画不顺畅,在它的末尾有一个"踢".

Answer 1

我不知道“自动滚动”是什么意思，但要更改集合视图单元格，您可以在自定义单元格类中使用didUpdateFocusInContext 。

override func didUpdateFocusInContext(context: UIFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator) {
    coordinator.addCoordinatedAnimations({ [unowned self] in
        if self.focused {
            self.titleTopConstraint.constant = 27

            self.titleLabel.textColor = UIColor.whiteColor()
        } else {
            self.titleTopConstraint.constant = 5

            self.titleLabel.textColor = UIColor(red: 100 / 255, green: 100 / 255, blue: 100 / 255, alpha: 1)
        }
        self.layoutIfNeeded()
    }, completion: nil)
}

或者，如果您没有自定义单元格，请使用UICollectionViewDelegate 中的didUpdateFocusInContext 。

func collectionView(collectionView: UICollectionView, didUpdateFocusInContext context: UICollectionViewFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator) {
    coordinator.addCoordinatedAnimations({ () -> Void in
        if let indexPath = context.nextFocusedIndexPath, let cell = collectionView.cellForItemAtIndexPath(indexPath) {
            // the cell that is going to be focused
        }
        if let indexPath = context.previouslyFocusedIndexPath, let cell = collectionView.cellForItemAtIndexPath(indexPath) {
            // the cell that is going to be unfocused
        }
    }, completion: nil)
}