UIKitdynamic：UITableViewCell内的附件

我的表格视图单元格在UIView包含一个圆圈，表示一个值。 我想将UIKit Dynamics附件行为添加到该圆，以便在滚动时稍微滞后。

我不想将单个单元格彼此附加，而只是将循环视图附加到UITableViewCell 。 细胞的其余部分应像往常一样滚动。

问题： UITableViewCell始终位于(0, 0) 。 如何将圆形添加到滚动时实际移动的视图？

Answer 1

我终于搞定了。 UITableView移动每个单元格和该单元格内包含的所有视图的坐标系统。 因此，我需要在滚动期间手动移动视图到UITableViewCell中，同时仍然参考初始定位点。

表格视图控制器：

 - (void)scrollViewDidScroll:(UIScrollView *)scrollView { BOOL scrollingUp = '\0'; if (self.lastContentOffset > scrollView.contentOffset.y) { scrollingUp = YES; } else if (self.lastContentOffset < scrollView.contentOffset.y) { scrollingUp = NO; } NSInteger offset = 64; // To compensate for the navigation bar. if (scrollingUp) { offset = offset - scrollView.contentOffset.y; } else { offset = offset + scrollView.contentOffset.y; } // Limit the offset so the views will not disappear during fast scrolling. if (offset > 10) { offset = 10; } else if (offset < -10) { offset = -10; } // lastContentOffset is an instance variable. self.lastContentOffset = scrollView.contentOffset.y; for (UITableViewCell *cell in self.tableView.visibleCells) { // Use CoreAnimation to prohibit flicker. [UIView beginAnimations:@"Display notification" context:nil]; [UIView setAnimationDuration:0.5f]; [UIView setAnimationBeginsFromCurrentState:YES]; cell.view.frame = CGRectMake(cell.view.frame.origin.x, offset, cell.view.frame.size.width, cell.view.frame.size.height); [UIView commitAnimations]; [cell.dynamicAnimator updateItemUsingCurrentState:cell.view]; } } 

表视图单元格：

 -(void)layoutSubviews { [super layoutSubviews]; // _view is the animated UIView. UIDynamicItemBehavior *viewBehavior = [[UIDynamicItemBehavior alloc] initWithItems:@[_view]]; viewBehavior.elasticity = 0.9f; UIAttachmentBehavior *attachmentBehaviorView = [[UIAttachmentBehavior alloc] initWithItem:_view attachedToAnchor:CGPointMake(_anchorView.frame.origin.x + _anchorView.frame.size.width / 2.0f, _anchorView.frame.origin.y + _anchorView.frame.size.height / 2.0f)]; attachmentBehaviorView.damping = 8.0f; attachmentBehaviorView.frequency = 4.0f; attachmentBehaviorView.length = 0.0f; [_dynamicAnimator addBehavior:viewBehavior]; [_dynamicAnimator addBehavior:attachmentBehaviorView]; } 

Answer 2

您可以在-[scrollViewDidScroll:]期间更改UIAttachmentBehavior的anchorPoint 。 你可以参考下面的代码片段：

 - (void)viewDidLoad { UIDynamicAnimator *animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view]; UIAttachmentBehavior *behavior1 = [[UIAttachmentBehavior alloc] initWithItem:self.circleView attachedToAnchor:[self tableViewAnchor]]; behavior1.length = 10.0; behavior1.damping = 0.3; behavior1.frequency = 2.5; [animator addBehavior:behavior1]; } - (void)scrollViewDidScroll:(UIScrollView *)scrollView { behavior1.anchorPoint = [self.tableView convertPoint:[self tableViewAnchor] toView:self.view]; } - (CGPoint)tableViewAnchor { return CGPointMake(160.0, 154.0); // return your target coordination wrt the table view } 

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