React-DnD中是否有任何选项,它可以根据拖拽对象启用拖放目标,拖拽目标在拖放目标中的面积超过50%？

Question

我一直在研究react-dnd(拖放组件).因此,基于鼠标指针识别远滴目标,我想知道是否有任何选项可以更改它,根据拖动对象需要识别的放置目标超过掉落目标的50%.

这与jQuery UI拖放功能类似,后者在droppable元素中包含"tolerance:intersect".

Answer 1

查看React-DnD 的可排序示例，特别是其中的悬停功能cardTarget：

const cardTarget = {
  hover(props, monitor, component) {
    const dragIndex = monitor.getItem().index;
    const hoverIndex = props.index;

    // Don't replace items with themselves
    if (dragIndex === hoverIndex) {
      return;
    }

    // Determine rectangle on screen
    const hoverBoundingRect = findDOMNode(component).getBoundingClientRect();

    // Get vertical middle
    const hoverMiddleY = (hoverBoundingRect.bottom - hoverBoundingRect.top) / 2;

    // Determine mouse position
    const clientOffset = monitor.getClientOffset();

    // Get pixels to the top
    const hoverClientY = clientOffset.y - hoverBoundingRect.top;

    // Only perform the move when the mouse has crossed half of the items height
    // When dragging downwards, only move when the cursor is below 50%
    // When dragging upwards, only move when the cursor is above 50%

    // Dragging downwards
    if (dragIndex < hoverIndex && hoverClientY < hoverMiddleY) {
      return;
    }

    // Dragging upwards
    if (dragIndex > hoverIndex && hoverClientY > hoverMiddleY) {
      return;
    }

    // Time to actually perform the action
    props.moveCard(dragIndex, hoverIndex);

    // Note: we're mutating the monitor item here!
    // Generally it's better to avoid mutations,
    // but it's good here for the sake of performance
    // to avoid expensive index searches.
    monitor.getItem().index = hoverIndex;
  }
};

我认为这两行就是您正在寻找的：

// Dragging downwards
if (dragIndex < hoverIndex && hoverClientY < hoverMiddleY) {
  return;
}

// Dragging upwards
if (dragIndex > hoverIndex && hoverClientY > hoverMiddleY) {
  return;
}

它会在悬停时检查悬停的项目是否超过了移动该项目的 50% 阈值，然后它将执行重新排序操作。