需求背景，工作中需要实现一个自定义打印模板的需求，能够实现单个及多个dom元素的同时拖拽，也能通过外部的input元素修改dom元素的样式。在npm和GitHub上找了各种已有的vue组件，不够灵活，效果都不是自己想要的
1.vue自定义指令
Vue.directive('dragx', (el, binding, vnode) => { // 默认参数 let defaultOpts = { dragDirection: 'n, e, s, w, ne, se, sw, nw, all', dragContainerId: '', // dragBarClass: '', // 类选择器 canDrag: true, canResize: true, multiSelect: false } let isMove = false let isResize = false let constraintDom let constraintRect let constraintRectHeight let constraintRectWidth binding.value = binding.value || {} let cfg = Object.assign({}, defaultOpts, binding.value) if (cfg.dragContainerId) { constraintDom = document.querySelector('#' + cfg.dragContainerId) constraintRect = constraintDom.getBoundingClientRect() constraintRectHeight = constraintRect.height constraintRectWidth = constraintRect.width } let getStyleNumValue = (style, key) => parseInt(style.getPropertyValue(key), 10) // 设置约束范围 function setConstraint (data) { if (cfg.dragContainerId) { if (data.left <= 0) data.left = 0 if (data.top <= 0) data.top = 0 if (data.top + data.height + data.borderTop + data.borderBottom >= constraintRectHeight) data.top = constraintRectHeight - data.height - data.borderTop - data.borderBottom if (data.left + data.width + data.borderLeft + data.borderRight > constraintRectWidth) data.left = constraintRectWidth - data.width - data.borderLeft - data.borderRight } } el.onmousemove = e => { if (cfg.dragBarClass.length > 0 && e.target.classList.contains(cfg.dragBarClass) && cfg.canDrag) { el.style.cursor = 'move' return } el.style.cursor = '' } el.onmouseleave = e => { el.style.cursor = '' } el.onmousedown = e => { let clickId = (e.target || e.srcElement).id let posData = { x: e.pageX, y: e.pageY } el.onmouseup = e => { // dom元素选中时发送active事件 if (!cfg.active) el.dispatchEvent(new CustomEvent('bindActive', { 'detail': { ...posData } })) } isMove = false if (cfg.dragBarClass.length > 0 && !e.target.classList.contains('icon-icon-resize')) { isMove = true isResize = false document.body.style.cursor = 'move' } else if (e.target.classList.contains('icon-icon-resize')) { isMove = false isResize = true } let style let rect let data let tableStyle style = window.getComputedStyle(el) rect = el.getBoundingClientRect() data = { width: getStyleNumValue(style, 'width'), height: getStyleNumValue(style, 'height'), left: getStyleNumValue(style, 'left'), top: getStyleNumValue(style, 'top'), borderLeft: getStyleNumValue(style, 'border-left-width'), borderTop: getStyleNumValue(style, 'border-top-width'), borderRight: getStyleNumValue(style, 'border-right-width'), borderBottom: getStyleNumValue(style, 'border-bottom-width'), deltX: e.pageX - rect.left, deltY: e.pageY - rect.top, startX: rect.left, startY: rect.top } if (el.id.indexOf(THSIGN) > -1 || el.id.indexOf(TDSIGN) > -1) { let table = document.getElementById(el.id.split(SEPARATOR)[0]) tableStyle = window.getComputedStyle(table) data.left = getStyleNumValue(tableStyle, 'left') data.top = getStyleNumValue(tableStyle, 'top') } document.onmousemove = edom => { if (edom.ctrlKey) return if (isResize) { data.width = Math.round(edom.pageX - data.startX + data.borderLeft + data.borderRight) data.height = Math.round(edom.pageY - data.startY + data.borderBottom + data.borderTop) } // 处理组件 移动 if (isMove && cfg.canDrag && (cfg.active || cfg.multiSelect)) { let targetPageX = edom.pageX let targetPageY = edom.pageY let deltX = targetPageX - data.startX - data.deltX let deltY = targetPageY - data.startY - data.deltY let newLeft = Math.round(getStyleNumValue(style, 'left') || '0', 10) + deltX let newTop = Math.round(getStyleNumValue(style, 'top') || '0', 10) + deltY data.left = Math.round(newLeft) data.top = Math.round(newTop) data.startX = data.startX + deltX data.startY = data.startY + deltY setConstraint(data) if (el.id.indexOf(THSIGN) > -1 || el.id.indexOf(TDSIGN) > -1) { let newLeft = Math.round(getStyleNumValue(tableStyle, 'left') || '0', 10) + deltX let newTop = Math.round(getStyleNumValue(tableStyle, 'top') || '0', 10) + deltY data.left = Math.round(newLeft) data.top = Math.round(newTop) } } if (cfg.multiSelect) { let domData = { el: clickId, x: edom.pageX, y: edom.pageY } // 移动多个元素时发送事件 bindUpdateDoms el.dispatchEvent(new CustomEvent('bindUpdateDoms', { detail: domData })) } else { // 移动单个元素移动时发送事件 bindUpdate el.dispatchEvent(new CustomEvent('bindUpdate', { detail: data })) } document.onmouseup = edom => { if (cfg.multiSelect && posData.x != edom.pageX && posData.y != edom.pageY) { let domData = { x: edom.pageX, y: edom.pageY } // 发送下面2个事件主要是为了实现操作的撤销和恢复功能，浏览器保存一个执行栈，一个移动表示一个事件 // 多个元素同时移动时发送事件 bindFinishMoveDoms el.dispatchEvent(new CustomEvent('bindFinishMoveDoms', { detail: domData })) } else if (posData.x != edom.pageX && posData.y != edom.pageY) { // 单个元素同时移动时发送事件 bindFinishMove el.dispatchEvent(new CustomEvent('bindFinishMove', { detail: data })) } document.body.style.cursor = '' document.onmousemove = null document.onmouseup = null isMove = false } } document.onmouseup = edom => { document.body.style.cursor = '' document.onmousemove = null document.onmouseup = null isMove = false } } })
2.自定义事件
在vue组件使用自定义指令并添加事件监听器
如果指令需要多个值，可以传入一个 JavaScript 对象字面量。记住，指令函数能够接受所有合法的 JavaScript 表达式。