JavaScript拖动元素在一个范围内移动

基于 jQuery
移动范围由 div 搭建(div 模仿表格)，卡片的移动不允许超出该范围
移动卡片会有一个淡蓝色卡片的标记出将要放置的位置
有禁止放置标记的位置，不允许卡片放置（会放到前一个可放置的位置）
卡片放置会覆盖单元格中的文字
卡片上的文字会跟随卡片的移动而改变
点击单元格，卡片会移动到该单元格

在这里插入图片描述

css 代码

.week-table {
  width: 660px;
  position: relative;
}

.week-table .thead-tr,
.week-table .tbody-tr {
  display: flex;
}

.week-table .thead-tr div,
.week-table .tbody-tr div {
  text-align: center;
  flex: 0 0 87px;
  height: 25px;
  border-right: 1px solid #ddd;
  border-top: 1px #ddd dashed;
  line-height: 25px;
  user-select: none;
  position: relative;
}

.week-table .thead-tr div:last-child,
.week-table .tbody-tr div:last-child {
  border-right: unset;
}

.week-table .thead-tr div:first-child,
.week-table .tbody-tr div:first-child {
  border-left: 1px #ddd dashed;
  flex: 0 0 50px;
}

.week-table .thead-tr div:last-child,
.week-table .tbody-tr div:last-child {
  border-right: 1px #ddd dashed;
}

.week-table .tbody-tr:last-child {
  border-bottom: 1px #ddd dashed;
}

.week-table .tr div:first-child {
  border-left: 1px #ddd dashed;
}

.week-table .thead-tr div {
  font-weight: bold;
  background-color: #f5f7fa;
}

.week-table .tbody-tr div:first-child {
  color: #fff;
}

.week-table .tbody-tr:nth-child(-n + 6) div:first-child {
  background-color: #3071a9;
}

.week-table .tbody-tr:nth-child(n + 7) div:first-child {
  background-color: #45b6b0;
}

.week-table .tbody-tr:nth-child(n + 11) div:first-child {
  background-color: #65c3df;
}

.week-table .tbody-tr .forbid {
  color: red;
  user-select: none;
  cursor: not-allowed;
}

.week-table .tbody-tr .card {
  background-color: #3071a9 !important;
  color: #333 !important;
  position: absolute;
  left: 1px;
  top: 1px;
  z-index: 2;
  user-select: none;
  border-radius: 4px;
}

.week-table .tbody-tr .highlight {
  background-color: #65c3df;
}

HTML 代码

  <div class="week-table">
      <div class="thead-tr">
        <div></div>
        <div>星期一</div>
        <div>星期二</div>
        <div>星期三</div>
        <div>星期四</div>
        <div>星期五</div>
        <div>星期六</div>
        <div>星期日</div>
      </div>
      <div class="tbody-tr">
        <div>1</div>
        <div></div>
        <div>
          <span>文字</span>
        </div>
        <div data-forbid="true">
          <span class="forbid">禁止放置</span>
        </div>
        <div>
          <div class="card" data-x="3" data-y="0" style="height: 72px; width: 84px">星期四 1~3格</div>
        </div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>2</div>
        <div><span>文字</span></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>3</div>
        <div><span>文字</span></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>4</div>
        <div><span>文字</span></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>5</div>
        <div><span>文字</span></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>6</div>
        <div><span>文字</span></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>7</div>
        <div><span>文字</span></div>
        <div></div>
        <div data-forbid="true">
          <span class="forbid">禁止放置</span>
        </div>
        <div data-forbid="true">
          <span class="forbid">禁止放置</span>
        </div>
        <div data-forbid="true">
          <span class="forbid">禁止放置</span>
        </div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>8</div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>9</div>
        <div><span>文字</span></div>
        <div data-forbid="true">
          <span class="forbid">禁止放置</span>
        </div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>10</div>
        <div><span>文字</span></div>
        <div></div>
        <div data-forbid="true">
          <span class="forbid">禁止放置</span>
        </div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>11</div>
        <div><span>文字</span></div>
        <div data-forbid="true">
          <span class="forbid">禁止放置</span>
        </div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="tbody-tr">
        <div>12</div>
        <div><span>文字</span></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
    </div>

JavaScript 代码

//----------- 点击移动卡片 ------------------
var $card = $('.week-table .card')
var $weekTable = $('.week-table')
var cardVerticalNumber = 3
var xNumber = 7
var yNumber = 12
positionCard($card, $weekTable, cardVerticalNumber, xNumber, yNumber)

function positionCard($card, $weekTable, cardVerticalNumber, xNumber, yNumber) {
  //--------  拖动卡片 --------
  var data = {}
  var tdHeight = 26 // 每一个 div 的高度
  var tdWidth = 88 // 每一个 div 的宽度
  var xNumber = xNumber // X 轴div数量，不含序列
  var yNumber = yNumber // Y轴div数量，不含星期列
  var xMoveMini = Math.floor(tdWidth / 4) // x轴最小移动距离，才开始计算方向
  var yMoveMini = Math.floor(tdHeight / 2) // y轴最小移动距离，才开始计算方向
  var cardHeight = $card.height()
  var cardWidth = $card.width()
  var cardVerticalNumber = cardVerticalNumber // 卡片占据的td数量
  var topLimit = 0 //顶部最大移动距离
  var bottomLimit = yNumber * tdHeight - cardHeight // 底部最大移动距离
  var leftLimit = 0 // 左边最大移动距离
  var rightLimit = xNumber * tdWidth - cardWidth // 右边最大移动距离
  var weekNameZh = ['一', '二', '三', '四', '五', '六', '日']
  $weekTable
    .find('.tbody-tr>div:not(:first-child)')
    .not('[data-forbid="true"]') // 要不要都行，isPutHere 也做了处理
    .on('click', function () {
      var $this = $(this)
      var xIndex = $this.index() - 1
      var yIndex = $this.parent().index() - 1
      var isPut = isPutHere(xIndex, yIndex)
      if (!isPut) return true
      data.newIndexX = xIndex
      data.newIndexY = yIndex
      moveCard(xIndex, yIndex, $this)
    })

  $card.mousedown(function (e) {
    var $this = $(this)
    var moveFlag = false // 防止别的事件触发
    data.oldIndexX = Number($this.attr('data-x'))
    data.oldIndexY = Number($this.attr('data-y'))
    data.left = e.pageX
    data.top = e.pageY
    data.sPositionX = data.oldIndexX * tdWidth
    data.sPositionY = data.oldIndexY * tdHeight
    var tempNewLeft = data.left // 上次移动时的位置信息，用于判断移动方向
    var tempNewTop = data.top // 上次移动时的位置信息，用于判断移动方向
    $(document).mousemove(function (e) {
      moveFlag = true
      data.newLeft = e.pageX
      data.newTop = e.pageY
      data.x = data.newLeft - data.left
      data.y = data.newTop - data.top
      data.newPositionX = data.sPositionX + data.x
      data.newPositionY = data.sPositionY + data.y
      var xMove = data.newLeft - tempNewLeft
      var yMove = data.newTop - tempNewTop

      // 元素没移动
      if (Math.abs(xMove) === 0 && Math.abs(yMove) === 0) return true

      if (data.newPositionX > rightLimit) {
        data.newPositionX = rightLimit
      }

      if (data.newPositionX < leftLimit) {
        data.newPositionX = leftLimit
      }

      if (data.newPositionY < topLimit) {
        data.newPositionY = topLimit
      }

      if (data.newPositionY > bottomLimit) {
        data.newPositionY = bottomLimit
      }

      // 当前移动，不超过一定距离不代表要移动
      if (Math.abs(xMove) > xMoveMini) {
        data.newIndexX = Math.ceil(data.x / tdWidth) + data.oldIndexX - 1

        // X index 的取值范围
        data.newIndexX = data.newIndexX <= 0 ? 0 : data.newIndexX
        data.newIndexX = data.newIndexX >= xNumber - 1 ? xNumber - 1 : data.newIndexX
      } else {
        data.newIndexX = data.oldIndexX
      }

      if (Math.abs(yMove) > yMoveMini) {
        data.newIndexY = Math.ceil(data.y / tdHeight) + data.oldIndexY - 1

        // Y index 的取值范围
        data.newIndexY = data.newIndexY <= 0 ? 0 : data.newIndexY
        data.newIndexY = data.newIndexY >= yNumber - cardVerticalNumber ? yNumber - cardVerticalNumber : data.newIndexY
      } else {
        data.newIndexY = data.oldIndexY
      }

      // 移动时，给将要移动到的地方一个高亮
      setHighlight(false, data.newIndexX, data.newIndexY)

      $card.css({
        left: data.newPositionX - data.sPositionX + 'px',
        top: data.newPositionY - data.sPositionY + 'px'
      })
    })

    $(document).mouseup(function (e) {
      if (!moveFlag) return
      moveFlag = false
      $(document).off('mousemove')
      tempNewLeft = data.newLeft
      tempNewTop = data.newTop

      setHighlight(true, data.newIndexX, data.newIndexY)
      $card.css({
        top: '1px',
        left: '1px'
      })

      // 不允许放置，放到上一个可用的位置
      if (isPutHere(data.newIndexX, data.newIndexY)) {
        moveCard(data.newIndexX, data.newIndexY)
      } else {
        moveCard(data.tempIndexX, data.tempIndexY)
      }
    })
  })

  function moveCard(x, y, $target) {
    setCardIndex(x, y)
    setCardInfo(x, y)
    var $parent = $target ? $target : getParent(x, y)
    $parent.append($card)
  }

  // 判断是否当前位置是否可放置
  function isPutHere(newX, newY) {
    var isPut = true
    // 当前 Y 轴 加上卡片高度超出Y 轴则直接返回 false
    if (newY + cardVerticalNumber > yNumber) return false
    for (var i = 0; i < cardVerticalNumber; i++) {
      var $parent = getParent(newX, newY + i)
      // 不允许放置的位置，高亮上一个可用的位置
      if ($parent.length <= 0 || isTdForbid($parent)) {
        isPut = false
      }
    }

    return isPut
  }

  function setHighlight(isRemoveClass, newX, newY) {
    $weekTable.find('.tbody-tr div').removeClass('highlight')

    var isPut = isPutHere(newX, newY)
    if (isPut) {
      // 存储上一个可用的位置
      data.tempIndexX = newX
      data.tempIndexY = newY
    }

    if (!isRemoveClass) {
      // 判断当前位置是否有禁用的 td
      for (var i = 0; i < cardVerticalNumber; i++) {
        if (isPut) {
          $parent = getParent(newX, newY + i)
        } else {
          $parent = getParent(data.tempIndexX, data.tempIndexY + i)
        }
        $parent.addClass('highlight')
      }
    }
  }

  function getParent(x, y) {
    return $weekTable
      .find('.tbody-tr')
      .eq(y)
      .find('>div')
      .eq(x + 1)
  }

  function isTdForbid($el) {
    return $el.attr('data-forbid')
  }

  function setCardIndex(x, y) {
    $card.attr('data-x', x)
    $card.attr('data-y', y)
  }

  function setCardInfo(x, y) {
    var dayName = weekNameZh[x]
    $card.text(`星期${dayName} ${y + 1}~${y + cardVerticalNumber}格`)
  }
}