UITableViewCell 中的 UIAttachmentBehavior答案

【问题标题】：UIAttachmentBehavior in UITableViewCellUITableViewCell 中的 UIAttachmentBehavior
【发布时间】：2013-10-19 00:53:48
【问题描述】：

我在我的 tableviewcell 中添加了一个水平 UIPanGestureRecognizer 来平移单元格的子视图，就像 ios7 邮件应用程序显示删除和更多选项的方式一样，这可以按预期工作

- (IBAction)slideCell:(UIPanGestureRecognizer *)sender
{

    CGPoint locationOfPan = [sender locationInView:self.tableView];
    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:locationOfPan];
    TestCell *cell = (TestCell *)[self.tableView cellForRowAtIndexPath:indexPath];    

    if (sender.state == UIGestureRecognizerStateChanged) {
        CGPoint translation = [sender translationInView:self.tableView];
        [cell.view setCenter:CGPointMake(cell.view.center.x + translation.x, cell.view.center.y)];
        [sender setTranslation:CGPointMake(0, 0) inView:self.tableView];
    }
}

我还想做的是向我的每个 UITableViewCells 添加一个带有锚点的 UIAttachmentBehavior，这样当我水平平移 cell.view 时，我会感到一些阻力，然后当我放手时，单元格中的视图被平移弹回到它在 x 轴上的原始锚点位置，这可能与 UIDynamics 有关吗？

我还可以将单元格的一侧设置为边界，以防止用户将包含的视图平移到它之外吗？

【问题讨论】：

标签： ios objective-c uitableview ios7 uikit-dynamics

【解决方案1】：

所以这里有代码来让它工作，它仍然需要调整以获得正确的感觉，但一切都按预期工作

在TestCell UITableViewCell 子类中

-(void)layoutSubviews{

    [super layoutSubviews];

    self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self];

    self.attachmentBehavior = [[UIAttachmentBehavior alloc] initWithItem:self.topView attachedToAnchor:self.topView.center];
    [self.attachmentBehavior setFrequency:4.5];
    [self.attachmentBehavior setDamping:0.3];

    UIGravityBehavior *gravityBehavior = [[UIGravityBehavior alloc] initWithItems:@[self.topView]];

    //gravity direction: right
    [gravityBehavior setGravityDirection:CGVectorMake(1.0, 0.0)];

    UICollisionBehavior *collisionBehavior = [[UICollisionBehavior alloc] initWithItems:@[self.topView]];
    [collisionBehavior addBoundaryWithIdentifier:@"rightBoundary" fromPoint:CGPointMake(320.0f, 0.0f) toPoint:CGPointMake(320.0f, self.contentView.frame.size.height)];
    [self.animator addBehavior:gravityBehavior];
    [self.animator addBehavior:collisionBehavior];

}

在我的 tableViewController 中

-(BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)gestureRecognizer {
    CGPoint translation = [gestureRecognizer translationInView:self.view.superview];
    // Check for horizontal gesture
    if (fabsf(translation.x) > fabsf(translation.y)) {
        return YES;
    }else{
        return NO;
    }

}


- (IBAction)slideCell:(UIPanGestureRecognizer *)sender
{

    CGPoint locationOfPan = [sender locationInView:self.tableView];
    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:locationOfPan];
    TestCell *cell = (TestCell *)[self.tableView cellForRowAtIndexPath:indexPath];

    if(sender.state == UIGestureRecognizerStateBegan){

        [cell.attachmentBehavior setAnchorPoint:cell.topView.center];
        [cell.animator addBehavior:cell.attachmentBehavior];

    }

    if (sender.state == UIGestureRecognizerStateChanged) {

        CGPoint translation = [sender translationInView:self.tableView];
        [cell.attachmentBehavior setAnchorPoint:CGPointMake(cell.topView.center.x + translation.x, cell.topView.center.y)];
        [sender setTranslation:CGPointMake(0, 0) inView:self.tableView];

    }

    if (sender.state == UIGestureRecognizerStateEnded) {
        //incase pan gesture has moved off the cell
        for(TestCell *cell in [self.tableView visibleCells]){
            [cell.animator removeBehavior:cell.attachmentBehavior];
        } 

    }

}

希望这可以帮助其他尝试做同样事情的人，如果有人知道 UIAttachmentBehavior 的设置以获得与 UIScrollview 相同的感觉，请告诉我，谢谢

【讨论】：