使用vue-grid-layout完成桌面拖拽布局功能(更改拖拽变换位置方式)

之前最原始的效果是当你移动一个box时 即使你没松开鼠标 每一个被你移动中碰撞到的box都会发生改变 这可能不是我们想要的

1. 我们通过创建一个historyLayout 拿来记录我们上一步的布局
2. 在watchitem()里比较 如果不是当前操作的box 使其的位置保持不变
3. 在moved()中调用一个调整位置的函数toChangePosition()
4. 使其可以达到 两两调换的效果 或者 将其插入指定位置 其他box会自动补位的效果

接下来的代码就是 自动补位的效果 简单的写了个（2*5）的demo 若有错误欢迎指正

<template>
  <grid-layout
    :layout="layout"
    :auto-size="false"
    :col-num="12"
    :row-height="100"
    :max-rows="100"
    :is-draggable="true"
    :is-resizable="false"
    :vertical-compact="false"
    :margin="[10, 10]"
    :use-css-transforms="true"
  >

    <grid-item v-for="item in layout" :key="item.i"
               :item="watchitem(item)"
               :x="item.x"
               :y="item.y"
               :w="item.w"
               :h="item.h"
               :i="item.i"
               @resize="resizeEvent"
               @move="moveEvent"
               @resized="resizedEvent"
               @moved="movedEvent"
    >
      {{item.i}}
    </grid-item>
  </grid-layout>
</template>

<script>
  import Vue from 'vue'
  import VueGridLayout from 'vue-grid-layout'
  Vue.use(VueGridLayout)

  var testLayout = [
    {"x":0,"y":0,"w":1,"h":1,"i":"0"},
    {"x":1,"y":0,"w":1,"h":1,"i":"1"},
    {"x":2,"y":0,"w":1,"h":1,"i":"2"},
    {"x":3,"y":0,"w":1,"h":1,"i":"3"},
    {"x":4,"y":0,"w":1,"h":1,"i":"4"},
    {"x":0,"y":1,"w":1,"h":1,"i":"5"},
    {"x":1,"y":1,"w":1,"h":1,"i":"6"},
    {"x":2,"y":1,"w":1,"h":1,"i":"7"},
    {"x":3,"y":1,"w":1,"h":1,"i":"8"},
    {"x":4,"y":1,"w":1,"h":1,"i":"9"},
  ];
  var historyLayout = [
    {"x":0,"y":0,"w":1,"h":1,"i":"0"},
    {"x":1,"y":0,"w":1,"h":1,"i":"1"},
    {"x":2,"y":0,"w":1,"h":1,"i":"2"},
    {"x":3,"y":0,"w":1,"h":1,"i":"3"},
    {"x":4,"y":0,"w":1,"h":1,"i":"4"},
    {"x":0,"y":1,"w":1,"h":1,"i":"5"},
    {"x":1,"y":1,"w":1,"h":1,"i":"6"},
    {"x":2,"y":1,"w":1,"h":1,"i":"7"},
    {"x":3,"y":1,"w":1,"h":1,"i":"8"},
    {"x":4,"y":1,"w":1,"h":1,"i":"9"},
  ];

  var GridLayout = VueGridLayout.GridLayout;
  var GridItem = VueGridLayout.GridItem;

  export default {
    name: 'Layout',
    components: {
      GridLayout,
      GridItem,
    },
    data () {
      return {
        layout: testLayout,
        newX:0,
        newY:0,
        curBox:'',
      }
    },
    mounted () {

    },
    methods:{
    
    watchitem:function(item) {
        //if(item.y>y_max ||item.x>x_max){
            //item.y=
            //item.x=
        //}
        //如果不是当前移动的 使其位置保持不变
        if(this.curBox != item.i) {
          for (let j = 0;historyLayout[j] != undefined; j++) {
            if(historyLayout[j].i == item.i) {
              item.x = historyLayout[j].x
              item.y = historyLayout[j].y
            }
          }
        }
        return item
    },
    toChangePosition:function(i){
        let layout = this.layout
        let hisLayout = historyLayout
        for (let j = 0; j < layout.length; j++) {
          if(layout[j].i == i) {
            let item = layout[j]
            for (let k = 0; k<hisLayout.length;k++) {
              if(hisLayout[k].i == i ) {
               let hisItem = hisLayout[k]
                let beforeX = hisItem.x
                let beforeY = hisItem.y
                let afterX = item.x
                let afterY = item.y
                for (let l = 0; l < hisLayout.length; l++) {
                 if(hisLayout[l].i != i) {
                   let needMoveobj = hisLayout[l]
                   //可能写的看上去比较繁琐  肯定有更优的写法
                   if(afterY == beforeY && needMoveobj.y == beforeY &&
                     ((needMoveobj.x >= item.x  && needMoveobj.x <= beforeX) || (needMoveobj.x <= item.x  && needMoveobj.x >= beforeX))) {
                     if(item.x > beforeX) {
                       needMoveobj.x = needMoveobj.x - 1
                     } else {
                       needMoveobj.x = needMoveobj.x + 1
                     }
                   }else if((beforeY == 1 && afterY == 0) && ((needMoveobj.y == beforeY && needMoveobj.x < beforeX) || (needMoveobj.y == afterY && needMoveobj.x >= afterX))) {
                     needMoveobj.x = needMoveobj.x +1
                     if(needMoveobj.x > 4) {
                       needMoveobj.x = 0
                       needMoveobj.y = needMoveobj.y +1
                     }
                   }else if((beforeY == 0 && afterY==1) && ((needMoveobj.y == beforeY && needMoveobj.x > beforeX) || (needMoveobj.y == afterY && needMoveobj.x <= afterX))) {
                     needMoveobj.x = needMoveobj.x - 1
                     if(needMoveobj.x <0) {
                       needMoveobj.x = 4
                       needMoveobj.y = needMoveobj.y - 1
                     }
                   }
                 }
                }
                hisItem.x = item.x
                hisItem.y = item.y
              }
            }
          }
        }
      },
    
      moveEvent: function(i, newX, newY,e){
        this.curBox = i
        //console.log(e)
        //console.log("MOVE i=" + i + ", X=" + newX + ", Y=" + newY);
      },      
      movedEvent: function(i, newX, newY,e){
        this.toChangePosition(i)
        //console.log(e)
        //console.log("MOVED i=" + i + ", X=" + newX + ", Y=" + newY);
      },
    }

  }
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
  .vue-grid-layout {
     position: relative;
     width:800px;
     height:450px;
     /*overflow: hidden;*/
     background: url('../../assets/desktop_background.png') no-repeat;
  }
  .vue-grid-layout>div {
     position: absolute;
     background: indianred;
  }
</style>